diff mbox series

[2/2,v3] drm/panel: ws2401: Add driver for WideChips WS2401

Message ID 20210707234315.242663-2-linus.walleij@linaro.org
State Superseded
Headers show
Series [1/2,v3] drm/panel: Add DT bindings for Samsung LMS380KF01 | expand

Commit Message

Linus Walleij July 7, 2021, 11:43 p.m. UTC
This adds a driver for panels based on the WideChips WS2401 display
controller. This display controller is used in the Samsung LMS380KF01
display found in the Samsung GT-I8160 (Codina) mobile phone and
possibly others.

As is common with Samsung displays manufacturer commands are necessary
to configure the display to a working state.

The display optionally supports internal backlight control, but can
also use an external backlight.

This driver re-uses the DBI infrastructure to communicate with the
display.

Cc: phone-devel@vger.kernel.org
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
ChangeLog v2->v3:
- Drop the ws2401_command() macro - we enhanced the
  mipi_dbi_command() to print errors for everyone instead.
- Read out MTP properly (used wrong variables)
- Register internal backlight if and only if the panel->backlight
  field is NULL after trying to look up external backlight.
ChangeLog v1->v2:
- Disable the backlight in ->unprepare() before entering sleep
  mode.
- If we are not using internal backlight, close the L2 access
  after initializing.
- Depromote some talkative dev_info()s to dev_dbg().
- Power up and read the MTP values before we register the display.
  This works fine and is probably how MTP is supposed to work.
- Fix the set-up of gamma values, this was found in the GT-I8160 HD
  kernel tree.
- Bail out properly if drm_panel_of_backlight() returns
  -EDEFER_PROBE.
- Drop OF from dependencies since drm_panel_of_backlight() has
  static inline stubs in the header file.
- Sort MAINTAINERS properly.
- Alphabetize includes
- Use format specifier %#02x so we get 0x... output in debug
- Drop unnecessary braces around if () in debug macro
- Drop unused <of.h> include.
---
 MAINTAINERS                                   |   7 +
 drivers/gpu/drm/panel/Kconfig                 |   9 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 .../gpu/drm/panel/panel-widechips-ws2401.c    | 436 ++++++++++++++++++
 4 files changed, 453 insertions(+)
 create mode 100644 drivers/gpu/drm/panel/panel-widechips-ws2401.c

-- 
2.31.1

Comments

Noralf Trønnes July 8, 2021, 2:48 p.m. UTC | #1
Den 08.07.2021 01.43, skrev Linus Walleij:
> This adds a driver for panels based on the WideChips WS2401 display

> controller. This display controller is used in the Samsung LMS380KF01

> display found in the Samsung GT-I8160 (Codina) mobile phone and

> possibly others.

> 

> As is common with Samsung displays manufacturer commands are necessary

> to configure the display to a working state.

> 

> The display optionally supports internal backlight control, but can

> also use an external backlight.

> 

> This driver re-uses the DBI infrastructure to communicate with the

> display.

> 

> Cc: phone-devel@vger.kernel.org

> Cc: Douglas Anderson <dianders@chromium.org>

> Cc: Noralf Trønnes <noralf@tronnes.org>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

> ---


Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Doug Anderson July 8, 2021, 8:04 p.m. UTC | #2
Hi,

On Wed, Jul 7, 2021 at 4:55 PM Linus Walleij <linus.walleij@linaro.org> wrote:
>

> This adds a driver for panels based on the WideChips WS2401 display

> controller. This display controller is used in the Samsung LMS380KF01

> display found in the Samsung GT-I8160 (Codina) mobile phone and

> possibly others.

>

> As is common with Samsung displays manufacturer commands are necessary

> to configure the display to a working state.

>

> The display optionally supports internal backlight control, but can

> also use an external backlight.

>

> This driver re-uses the DBI infrastructure to communicate with the

> display.

>

> Cc: phone-devel@vger.kernel.org

> Cc: Douglas Anderson <dianders@chromium.org>

> Cc: Noralf Trønnes <noralf@tronnes.org>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

> ---

> ChangeLog v2->v3:

> - Drop the ws2401_command() macro - we enhanced the

>   mipi_dbi_command() to print errors for everyone instead.

> - Read out MTP properly (used wrong variables)

> - Register internal backlight if and only if the panel->backlight

>   field is NULL after trying to look up external backlight.

> ChangeLog v1->v2:

> - Disable the backlight in ->unprepare() before entering sleep

>   mode.

> - If we are not using internal backlight, close the L2 access

>   after initializing.

> - Depromote some talkative dev_info()s to dev_dbg().

> - Power up and read the MTP values before we register the display.

>   This works fine and is probably how MTP is supposed to work.

> - Fix the set-up of gamma values, this was found in the GT-I8160 HD

>   kernel tree.

> - Bail out properly if drm_panel_of_backlight() returns

>   -EDEFER_PROBE.

> - Drop OF from dependencies since drm_panel_of_backlight() has

>   static inline stubs in the header file.

> - Sort MAINTAINERS properly.

> - Alphabetize includes

> - Use format specifier %#02x so we get 0x... output in debug

> - Drop unnecessary braces around if () in debug macro

> - Drop unused <of.h> include.

> ---

>  MAINTAINERS                                   |   7 +

>  drivers/gpu/drm/panel/Kconfig                 |   9 +

>  drivers/gpu/drm/panel/Makefile                |   1 +

>  .../gpu/drm/panel/panel-widechips-ws2401.c    | 436 ++++++++++++++++++

>  4 files changed, 453 insertions(+)


Looks nice to me now.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Jagan Teki July 9, 2021, 9:25 a.m. UTC | #3
On Thu, Jul 8, 2021 at 5:25 AM Linus Walleij <linus.walleij@linaro.org> wrote:
>

> This adds a driver for panels based on the WideChips WS2401 display

> controller. This display controller is used in the Samsung LMS380KF01

> display found in the Samsung GT-I8160 (Codina) mobile phone and

> possibly others.

>

> As is common with Samsung displays manufacturer commands are necessary

> to configure the display to a working state.

>

> The display optionally supports internal backlight control, but can

> also use an external backlight.

>

> This driver re-uses the DBI infrastructure to communicate with the

> display.

>

> Cc: phone-devel@vger.kernel.org

> Cc: Douglas Anderson <dianders@chromium.org>

> Cc: Noralf Trønnes <noralf@tronnes.org>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

> ---

> ChangeLog v2->v3:

> - Drop the ws2401_command() macro - we enhanced the

>   mipi_dbi_command() to print errors for everyone instead.

> - Read out MTP properly (used wrong variables)

> - Register internal backlight if and only if the panel->backlight

>   field is NULL after trying to look up external backlight.

> ChangeLog v1->v2:

> - Disable the backlight in ->unprepare() before entering sleep

>   mode.

> - If we are not using internal backlight, close the L2 access

>   after initializing.

> - Depromote some talkative dev_info()s to dev_dbg().

> - Power up and read the MTP values before we register the display.

>   This works fine and is probably how MTP is supposed to work.

> - Fix the set-up of gamma values, this was found in the GT-I8160 HD

>   kernel tree.

> - Bail out properly if drm_panel_of_backlight() returns

>   -EDEFER_PROBE.

> - Drop OF from dependencies since drm_panel_of_backlight() has

>   static inline stubs in the header file.

> - Sort MAINTAINERS properly.

> - Alphabetize includes

> - Use format specifier %#02x so we get 0x... output in debug

> - Drop unnecessary braces around if () in debug macro

> - Drop unused <of.h> include.

> ---

>  MAINTAINERS                                   |   7 +

>  drivers/gpu/drm/panel/Kconfig                 |   9 +

>  drivers/gpu/drm/panel/Makefile                |   1 +

>  .../gpu/drm/panel/panel-widechips-ws2401.c    | 436 ++++++++++++++++++

>  4 files changed, 453 insertions(+)

>  create mode 100644 drivers/gpu/drm/panel/panel-widechips-ws2401.c

>

> diff --git a/MAINTAINERS b/MAINTAINERS

> index bd7aff0c120f..10bba4be1678 100644

> --- a/MAINTAINERS

> +++ b/MAINTAINERS

> @@ -5956,6 +5956,13 @@ T:       git git://people.freedesktop.org/~sroland/linux

>  F:     drivers/gpu/drm/vmwgfx/

>  F:     include/uapi/drm/vmwgfx_drm.h

>

> +DRM DRIVER FOR WIDECHIPS WS2401 PANELS

> +M:     Linus Walleij <linus.walleij@linaro.org>

> +S:     Maintained

> +T:     git git://anongit.freedesktop.org/drm/drm-misc

> +F:     Documentation/devicetree/bindings/display/panel/samsung,lms380kf01.yaml

> +F:     drivers/gpu/drm/panel/panel-widechips-ws2401.c

> +

>  DRM DRIVERS

>  M:     David Airlie <airlied@linux.ie>

>  M:     Daniel Vetter <daniel@ffwll.ch>

> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig

> index 4894913936e9..319fa44c4bc9 100644

> --- a/drivers/gpu/drm/panel/Kconfig

> +++ b/drivers/gpu/drm/panel/Kconfig

> @@ -552,6 +552,15 @@ config DRM_PANEL_VISIONOX_RM69299

>           Say Y here if you want to enable support for Visionox

>           RM69299  DSI Video Mode panel.

>

> +config DRM_PANEL_WIDECHIPS_WS2401

> +       tristate "Widechips WS2401 DPI panel driver"

> +       depends on SPI && GPIOLIB

> +       depends on BACKLIGHT_CLASS_DEVICE

> +       select DRM_MIPI_DBI

> +       help

> +         Say Y here if you want to enable support for the Widechips WS2401 DPI

> +         480x800 display controller used in panels such as Samsung LMS380KF01.

> +

>  config DRM_PANEL_XINPENG_XPP055C272

>         tristate "Xinpeng XPP055C272 panel driver"

>         depends on OF

> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile

> index cae4d976c069..d94c27df17aa 100644

> --- a/drivers/gpu/drm/panel/Makefile

> +++ b/drivers/gpu/drm/panel/Makefile

> @@ -58,4 +58,5 @@ obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o

>  obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o

>  obj-$(CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA) += panel-truly-nt35597.o

>  obj-$(CONFIG_DRM_PANEL_VISIONOX_RM69299) += panel-visionox-rm69299.o

> +obj-$(CONFIG_DRM_PANEL_WIDECHIPS_WS2401) += panel-widechips-ws2401.o

>  obj-$(CONFIG_DRM_PANEL_XINPENG_XPP055C272) += panel-xinpeng-xpp055c272.o

> diff --git a/drivers/gpu/drm/panel/panel-widechips-ws2401.c b/drivers/gpu/drm/panel/panel-widechips-ws2401.c

> new file mode 100644

> index 000000000000..95825063f812

> --- /dev/null

> +++ b/drivers/gpu/drm/panel/panel-widechips-ws2401.c

> @@ -0,0 +1,436 @@

> +// SPDX-License-Identifier: GPL-2.0

> +/*

> + * Panel driver for the WideChips WS2401 480x800 DPI RGB panel, used in

> + * the Samsung Mobile Display (SMD) LMS380KF01.

> + * Found in the Samsung Galaxy Ace 2 GT-I8160 mobile phone.

> + * Linus Walleij <linus.walleij@linaro.org>

> + * Inspired by code and know-how in the vendor driver by Gareth Phillips.

> + */

> +#include <drm/drm_mipi_dbi.h>

> +#include <drm/drm_modes.h>

> +#include <drm/drm_panel.h>

> +

> +#include <linux/backlight.h>

> +#include <linux/delay.h>

> +#include <linux/gpio/consumer.h>

> +#include <linux/init.h>

> +#include <linux/kernel.h>

> +#include <linux/media-bus-format.h>

> +#include <linux/module.h>

> +#include <linux/regulator/consumer.h>

> +#include <linux/spi/spi.h>

> +

> +#include <video/mipi_display.h>

> +

> +#define WS2401_RESCTL                  0xb8 /* Resolution select control */

> +#define WS2401_PSMPS                   0xbd /* SMPS positive control */

> +#define WS2401_NSMPS                   0xbe /* SMPS negative control */

> +#define WS2401_SMPS                    0xbf

> +#define WS2401_BCMODE                  0xc1 /* Backlight control mode */

> +#define WS2401_WRBLCTL                 0xc3 /* Backlight control */

> +#define WS2401_WRDISBV                 0xc4 /* Write manual brightness */

> +#define WS2401_WRCTRLD                 0xc6 /* Write BL control */

> +#define WS2401_WRMIE                   0xc7 /* Write MIE mode */

> +#define WS2401_READ_ID1                        0xda /* Read panel ID 1 */

> +#define WS2401_READ_ID2                        0xdb /* Read panel ID 2 */

> +#define WS2401_READ_ID3                        0xdc /* Read panel ID 3 */

> +#define WS2401_GAMMA_R1                        0xe7 /* Gamma red 1 */

> +#define WS2401_GAMMA_G1                        0xe8 /* Gamma green 1 */

> +#define WS2401_GAMMA_B1                        0xe9 /* Gamma blue 1 */

> +#define WS2401_GAMMA_R2                        0xea /* Gamma red 2 */

> +#define WS2401_GAMMA_G2                        0xeb /* Gamma green 2 */

> +#define WS2401_GAMMA_B2                        0xec /* Gamma blue 2 */

> +#define WS2401_PASSWD1                 0xf0 /* Password command for level 2 */

> +#define WS2401_DISCTL                  0xf2 /* Display control */

> +#define WS2401_PWRCTL                  0xf3 /* Power control */

> +#define WS2401_VCOMCTL                 0xf4 /* VCOM control */

> +#define WS2401_SRCCTL                  0xf5 /* Source control */

> +#define WS2401_PANELCTL                        0xf6 /* Panel control */

> +

> +static const u8 ws2401_dbi_read_commands[] = {

> +       WS2401_READ_ID1,

> +       WS2401_READ_ID2,

> +       WS2401_READ_ID3,

> +       0, /* sentinel */

> +};

> +

> +/**

> + * struct ws2401 - state container for a panel controlled by the WS2401

> + * controller

> + */

> +struct ws2401 {

> +       /** @dev: the container device */

> +       struct device *dev;

> +       /** @dbi: the DBI bus abstraction handle */

> +       struct mipi_dbi dbi;

> +       /** @panel: the DRM panel instance for this device */

> +       struct drm_panel panel;

> +       /** @width: the width of this panel in mm */

> +       u32 width;

> +       /** @height: the height of this panel in mm */

> +       u32 height;

> +       /** @reset: reset GPIO line */

> +       struct gpio_desc *reset;

> +       /** @regulators: VCCIO and VIO supply regulators */

> +       struct regulator_bulk_data regulators[2];

> +       /** @bl: Backlight, if using internal backlight */

> +       struct backlight_device *bl;

> +};

> +

> +static const struct drm_display_mode lms380kf01_480_800_mode = {

> +       /*

> +        * The vendor driver states that the "SMD panel" has a clock

> +        * frequency of 49920000 Hz / 2 = 24960000 Hz.

> +        */

> +       .clock = 24960,

> +       .hdisplay = 480,

> +       .hsync_start = 480 + 8,

> +       .hsync_end = 480 + 8 + 10,

> +       .htotal = 480 + 8 + 10 + 8,

> +       .vdisplay = 800,

> +       .vsync_start = 800 + 8,

> +       .vsync_end = 800 + 8 + 2,

> +       .vtotal = 800 + 8 + 2 + 18,

> +       .width_mm = 50,

> +       .height_mm = 84,

> +       .flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,

> +};

> +

> +static inline struct ws2401 *to_ws2401(struct drm_panel *panel)

> +{

> +       return container_of(panel, struct ws2401, panel);

> +}

> +

> +static void ws2401_read_mtp_id(struct ws2401 *ws)

> +{

> +       struct mipi_dbi *dbi = &ws->dbi;

> +       u8 id1, id2, id3;

> +       int ret;

> +

> +       ret = mipi_dbi_command_read(dbi, WS2401_READ_ID1, &id1);

> +       if (ret) {

> +               dev_err(ws->dev, "unable to read MTP ID 1\n");

> +               return;

> +       }

> +       ret = mipi_dbi_command_read(dbi, WS2401_READ_ID2, &id2);

> +       if (ret) {

> +               dev_err(ws->dev, "unable to read MTP ID 2\n");

> +               return;

> +       }

> +       ret = mipi_dbi_command_read(dbi, WS2401_READ_ID3, &id3);

> +       if (ret) {

> +               dev_err(ws->dev, "unable to read MTP ID 3\n");

> +               return;

> +       }

> +       dev_info(ws->dev, "MTP ID: %02x %02x %02x\n", id1, id2, id3);

> +}

> +

> +static int ws2401_power_on(struct ws2401 *ws)

> +{

> +       struct mipi_dbi *dbi = &ws->dbi;

> +       int ret;

> +

> +       /* Power up */

> +       ret = regulator_bulk_enable(ARRAY_SIZE(ws->regulators),

> +                                   ws->regulators);

> +       if (ret) {

> +               dev_err(ws->dev, "failed to enable regulators: %d\n", ret);

> +               return ret;

> +       }

> +       msleep(10);

> +

> +       /* Assert reset >=1 ms */

> +       gpiod_set_value_cansleep(ws->reset, 1);

> +       usleep_range(1000, 5000);

> +       /* De-assert reset */

> +       gpiod_set_value_cansleep(ws->reset, 0);

> +       /* Wait >= 10 ms */

> +       msleep(10);

> +       dev_dbg(ws->dev, "de-asserted RESET\n");


Just a small comment, are these delays are as per init sequence
mentioned in datasheet?

Jagan,
Linus Walleij July 9, 2021, 3:03 p.m. UTC | #4
On Fri, Jul 9, 2021 at 11:25 AM Jagan Teki <jagan@amarulasolutions.com> wrote:

> > +       /* Assert reset >=1 ms */

> > +       gpiod_set_value_cansleep(ws->reset, 1);

> > +       usleep_range(1000, 5000);

> > +       /* De-assert reset */

> > +       gpiod_set_value_cansleep(ws->reset, 0);

> > +       /* Wait >= 10 ms */

> > +       msleep(10);

> > +       dev_dbg(ws->dev, "de-asserted RESET\n");

>

> Just a small comment, are these delays are as per init sequence

> mentioned in datasheet?


As so often with Samsung mobile displays there is no datasheet.

These delays are in the product source code tree for the
GT-I8160 (Codina) mobile phone, actually in the glue integration
code. WideChips were acquired by some other firm and do not
exist anymore so I can't ask them, and asking Samsung for anything
else than source code doesn't work either. (I have tried.)

Yours,
Linus Walleij
Sam Ravnborg July 9, 2021, 6:01 p.m. UTC | #5
Hi Linus,

On Thu, Jul 08, 2021 at 01:43:15AM +0200, Linus Walleij wrote:
> This adds a driver for panels based on the WideChips WS2401 display

> controller. This display controller is used in the Samsung LMS380KF01

> display found in the Samsung GT-I8160 (Codina) mobile phone and

> possibly others.

> 

> As is common with Samsung displays manufacturer commands are necessary

> to configure the display to a working state.

> 

> The display optionally supports internal backlight control, but can

> also use an external backlight.

> 

> This driver re-uses the DBI infrastructure to communicate with the

> display.

> 

> Cc: phone-devel@vger.kernel.org

> Cc: Douglas Anderson <dianders@chromium.org>

> Cc: Noralf Trønnes <noralf@tronnes.org>

> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>


Sorry for being late here. Some backlight related comments in the
following. The rest looks good.

	Sam

> ---

> ChangeLog v2->v3:

> - Drop the ws2401_command() macro - we enhanced the

>   mipi_dbi_command() to print errors for everyone instead.

> - Read out MTP properly (used wrong variables)

> - Register internal backlight if and only if the panel->backlight

>   field is NULL after trying to look up external backlight.

> ChangeLog v1->v2:

> - Disable the backlight in ->unprepare() before entering sleep

>   mode.

> - If we are not using internal backlight, close the L2 access

>   after initializing.

> - Depromote some talkative dev_info()s to dev_dbg().

> - Power up and read the MTP values before we register the display.

>   This works fine and is probably how MTP is supposed to work.

> - Fix the set-up of gamma values, this was found in the GT-I8160 HD

>   kernel tree.

> - Bail out properly if drm_panel_of_backlight() returns

>   -EDEFER_PROBE.

> - Drop OF from dependencies since drm_panel_of_backlight() has

>   static inline stubs in the header file.

> - Sort MAINTAINERS properly.

> - Alphabetize includes

> - Use format specifier %#02x so we get 0x... output in debug

> - Drop unnecessary braces around if () in debug macro

> - Drop unused <of.h> include.

> ---

>  MAINTAINERS                                   |   7 +

>  drivers/gpu/drm/panel/Kconfig                 |   9 +

>  drivers/gpu/drm/panel/Makefile                |   1 +

>  .../gpu/drm/panel/panel-widechips-ws2401.c    | 436 ++++++++++++++++++

>  4 files changed, 453 insertions(+)

>  create mode 100644 drivers/gpu/drm/panel/panel-widechips-ws2401.c

> 

> diff --git a/MAINTAINERS b/MAINTAINERS

> index bd7aff0c120f..10bba4be1678 100644

> --- a/MAINTAINERS

> +++ b/MAINTAINERS

> @@ -5956,6 +5956,13 @@ T:	git git://people.freedesktop.org/~sroland/linux

>  F:	drivers/gpu/drm/vmwgfx/

>  F:	include/uapi/drm/vmwgfx_drm.h

>  

> +DRM DRIVER FOR WIDECHIPS WS2401 PANELS

> +M:	Linus Walleij <linus.walleij@linaro.org>

> +S:	Maintained

> +T:	git git://anongit.freedesktop.org/drm/drm-misc

> +F:	Documentation/devicetree/bindings/display/panel/samsung,lms380kf01.yaml

> +F:	drivers/gpu/drm/panel/panel-widechips-ws2401.c

> +

>  DRM DRIVERS

>  M:	David Airlie <airlied@linux.ie>

>  M:	Daniel Vetter <daniel@ffwll.ch>

> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig

> index 4894913936e9..319fa44c4bc9 100644

> --- a/drivers/gpu/drm/panel/Kconfig

> +++ b/drivers/gpu/drm/panel/Kconfig

> @@ -552,6 +552,15 @@ config DRM_PANEL_VISIONOX_RM69299

>  	  Say Y here if you want to enable support for Visionox

>  	  RM69299  DSI Video Mode panel.

>  

> +config DRM_PANEL_WIDECHIPS_WS2401

> +	tristate "Widechips WS2401 DPI panel driver"

> +	depends on SPI && GPIOLIB

> +	depends on BACKLIGHT_CLASS_DEVICE

> +	select DRM_MIPI_DBI

> +	help

> +	  Say Y here if you want to enable support for the Widechips WS2401 DPI

> +	  480x800 display controller used in panels such as Samsung LMS380KF01.

Maybe add "e.g. found in the Samsung GT-I8160 (Codina) mobile phone"
As I assume this will be the most frequent user anyway.

> +

>  config DRM_PANEL_XINPENG_XPP055C272

>  	tristate "Xinpeng XPP055C272 panel driver"

>  	depends on OF

> diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile

> index cae4d976c069..d94c27df17aa 100644

> --- a/drivers/gpu/drm/panel/Makefile

> +++ b/drivers/gpu/drm/panel/Makefile

> @@ -58,4 +58,5 @@ obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o

>  obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o

>  obj-$(CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA) += panel-truly-nt35597.o

>  obj-$(CONFIG_DRM_PANEL_VISIONOX_RM69299) += panel-visionox-rm69299.o

> +obj-$(CONFIG_DRM_PANEL_WIDECHIPS_WS2401) += panel-widechips-ws2401.o

>  obj-$(CONFIG_DRM_PANEL_XINPENG_XPP055C272) += panel-xinpeng-xpp055c272.o

> diff --git a/drivers/gpu/drm/panel/panel-widechips-ws2401.c b/drivers/gpu/drm/panel/panel-widechips-ws2401.c

> new file mode 100644

> index 000000000000..95825063f812

> --- /dev/null

> +++ b/drivers/gpu/drm/panel/panel-widechips-ws2401.c

> @@ -0,0 +1,436 @@

> +// SPDX-License-Identifier: GPL-2.0

> +/*

> + * Panel driver for the WideChips WS2401 480x800 DPI RGB panel, used in

> + * the Samsung Mobile Display (SMD) LMS380KF01.

> + * Found in the Samsung Galaxy Ace 2 GT-I8160 mobile phone.

> + * Linus Walleij <linus.walleij@linaro.org>

> + * Inspired by code and know-how in the vendor driver by Gareth Phillips.

> + */

> +#include <drm/drm_mipi_dbi.h>

> +#include <drm/drm_modes.h>

> +#include <drm/drm_panel.h>

> +

> +#include <linux/backlight.h>

> +#include <linux/delay.h>

> +#include <linux/gpio/consumer.h>

> +#include <linux/init.h>

> +#include <linux/kernel.h>

> +#include <linux/media-bus-format.h>

> +#include <linux/module.h>

> +#include <linux/regulator/consumer.h>

> +#include <linux/spi/spi.h>

> +

> +#include <video/mipi_display.h>

> +

> +#define WS2401_RESCTL			0xb8 /* Resolution select control */

> +#define WS2401_PSMPS			0xbd /* SMPS positive control */

> +#define WS2401_NSMPS			0xbe /* SMPS negative control */

> +#define WS2401_SMPS			0xbf

> +#define WS2401_BCMODE			0xc1 /* Backlight control mode */

> +#define WS2401_WRBLCTL			0xc3 /* Backlight control */

> +#define WS2401_WRDISBV			0xc4 /* Write manual brightness */

> +#define WS2401_WRCTRLD			0xc6 /* Write BL control */

> +#define WS2401_WRMIE			0xc7 /* Write MIE mode */

> +#define WS2401_READ_ID1			0xda /* Read panel ID 1 */

> +#define WS2401_READ_ID2			0xdb /* Read panel ID 2 */

> +#define WS2401_READ_ID3			0xdc /* Read panel ID 3 */

> +#define WS2401_GAMMA_R1			0xe7 /* Gamma red 1 */

> +#define WS2401_GAMMA_G1			0xe8 /* Gamma green 1 */

> +#define WS2401_GAMMA_B1			0xe9 /* Gamma blue 1 */

> +#define WS2401_GAMMA_R2			0xea /* Gamma red 2 */

> +#define WS2401_GAMMA_G2			0xeb /* Gamma green 2 */

> +#define WS2401_GAMMA_B2			0xec /* Gamma blue 2 */

> +#define WS2401_PASSWD1			0xf0 /* Password command for level 2 */

> +#define WS2401_DISCTL			0xf2 /* Display control */

> +#define WS2401_PWRCTL			0xf3 /* Power control */

> +#define WS2401_VCOMCTL			0xf4 /* VCOM control */

> +#define WS2401_SRCCTL			0xf5 /* Source control */

> +#define WS2401_PANELCTL			0xf6 /* Panel control */

> +

> +static const u8 ws2401_dbi_read_commands[] = {

> +	WS2401_READ_ID1,

> +	WS2401_READ_ID2,

> +	WS2401_READ_ID3,

> +	0, /* sentinel */

> +};

> +

> +/**

> + * struct ws2401 - state container for a panel controlled by the WS2401

> + * controller

> + */

> +struct ws2401 {

> +	/** @dev: the container device */

> +	struct device *dev;

> +	/** @dbi: the DBI bus abstraction handle */

> +	struct mipi_dbi dbi;

> +	/** @panel: the DRM panel instance for this device */

> +	struct drm_panel panel;

> +	/** @width: the width of this panel in mm */

> +	u32 width;

> +	/** @height: the height of this panel in mm */

> +	u32 height;

> +	/** @reset: reset GPIO line */

> +	struct gpio_desc *reset;

> +	/** @regulators: VCCIO and VIO supply regulators */

> +	struct regulator_bulk_data regulators[2];

> +	/** @bl: Backlight, if using internal backlight */

> +	struct backlight_device *bl;

> +};

> +

> +static const struct drm_display_mode lms380kf01_480_800_mode = {

> +	/*

> +	 * The vendor driver states that the "SMD panel" has a clock

> +	 * frequency of 49920000 Hz / 2 = 24960000 Hz.

> +	 */

> +	.clock = 24960,

> +	.hdisplay = 480,

> +	.hsync_start = 480 + 8,

> +	.hsync_end = 480 + 8 + 10,

> +	.htotal = 480 + 8 + 10 + 8,

> +	.vdisplay = 800,

> +	.vsync_start = 800 + 8,

> +	.vsync_end = 800 + 8 + 2,

> +	.vtotal = 800 + 8 + 2 + 18,

> +	.width_mm = 50,

> +	.height_mm = 84,

> +	.flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,

> +};

> +

> +static inline struct ws2401 *to_ws2401(struct drm_panel *panel)

> +{

> +	return container_of(panel, struct ws2401, panel);

> +}

> +

> +static void ws2401_read_mtp_id(struct ws2401 *ws)

> +{

> +	struct mipi_dbi *dbi = &ws->dbi;

> +	u8 id1, id2, id3;

> +	int ret;

> +

> +	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID1, &id1);

> +	if (ret) {

> +		dev_err(ws->dev, "unable to read MTP ID 1\n");

> +		return;

> +	}

> +	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID2, &id2);

> +	if (ret) {

> +		dev_err(ws->dev, "unable to read MTP ID 2\n");

> +		return;

> +	}

> +	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID3, &id3);

> +	if (ret) {

> +		dev_err(ws->dev, "unable to read MTP ID 3\n");

> +		return;

> +	}

> +	dev_info(ws->dev, "MTP ID: %02x %02x %02x\n", id1, id2, id3);

> +}

> +

> +static int ws2401_power_on(struct ws2401 *ws)

> +{

> +	struct mipi_dbi *dbi = &ws->dbi;

> +	int ret;

> +

> +	/* Power up */

> +	ret = regulator_bulk_enable(ARRAY_SIZE(ws->regulators),

> +				    ws->regulators);

> +	if (ret) {

> +		dev_err(ws->dev, "failed to enable regulators: %d\n", ret);

> +		return ret;

> +	}

> +	msleep(10);

> +

> +	/* Assert reset >=1 ms */

> +	gpiod_set_value_cansleep(ws->reset, 1);

> +	usleep_range(1000, 5000);

> +	/* De-assert reset */

> +	gpiod_set_value_cansleep(ws->reset, 0);

> +	/* Wait >= 10 ms */

> +	msleep(10);

> +	dev_dbg(ws->dev, "de-asserted RESET\n");

> +

> +	/*

> +	 * Exit sleep mode and initialize display - some hammering is

> +	 * necessary.

> +	 */

> +	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);

> +	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);

> +	msleep(50);

> +

> +	/* Magic to unlock level 2 control of the display */

> +	mipi_dbi_command(dbi, WS2401_PASSWD1, 0x5a, 0x5a);

> +	/* Configure resolution to 480RGBx800 */

> +	mipi_dbi_command(dbi, WS2401_RESCTL, 0x12);

> +	/* Set addressing mode Flip V(d0), Flip H(d1) RGB/BGR(d3) */

> +	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, 0x01);

> +	/* Set pixel format: 24 bpp */

> +	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, 0x70);

> +	mipi_dbi_command(dbi, WS2401_SMPS, 0x00, 0x0f);

> +	mipi_dbi_command(dbi, WS2401_PSMPS, 0x06, 0x03, /* DDVDH: 4.6v */

> +			 0x7e, 0x03, 0x12, 0x37);

> +	mipi_dbi_command(dbi, WS2401_NSMPS, 0x06, 0x03, /* DDVDH: -4.6v */

> +			 0x7e, 0x02, 0x15, 0x37);

> +	mipi_dbi_command(dbi, WS2401_SMPS, 0x02, 0x0f);

> +	mipi_dbi_command(dbi, WS2401_PWRCTL, 0x10, 0xA9, 0x00, 0x01, 0x44,

> +			 0xb4,	/* VGH:16.1v, VGL:-13.8v */

> +			 0x50,	/* GREFP:4.2v (default) */

> +			 0x50,	/* GREFN:-4.2v (default) */

> +			 0x00,

> +			 0x44);	/* VOUTL:-10v (default) */

> +	mipi_dbi_command(dbi, WS2401_DISCTL, 0x01, 0x00, 0x00, 0x00, 0x14,

> +			 0x16);

> +	mipi_dbi_command(dbi, WS2401_VCOMCTL, 0x30, 0x53, 0x53);

> +	mipi_dbi_command(dbi, WS2401_SRCCTL, 0x03, 0x0C, 0x00, 0x00, 0x00,

> +			 0x01,	/* 2 dot inversion */

> +			 0x01, 0x06, 0x03);

> +	mipi_dbi_command(dbi, WS2401_PANELCTL, 0x14, 0x00, 0x80, 0x00);

> +	mipi_dbi_command(dbi, WS2401_WRMIE, 0x01);

> +

> +	/* Set up gamma, probably these are P-gamma and N-gamma for each color */

> +	mipi_dbi_command(dbi, WS2401_GAMMA_R1, 0x00,

> +			 0x5b, 0x42, 0x41, 0x3f, 0x42, 0x3d, 0x38, 0x2e,

> +			 0x2b, 0x2a, 0x27, 0x22, 0x27, 0x0f, 0x00, 0x00);

> +	mipi_dbi_command(dbi, WS2401_GAMMA_R2, 0x00,

> +			 0x5b, 0x42, 0x41, 0x3f, 0x42, 0x3d, 0x38, 0x2e,

> +			 0x2b, 0x2a, 0x27, 0x22, 0x27, 0x0f, 0x00, 0x00);

> +	mipi_dbi_command(dbi, WS2401_GAMMA_G1, 0x00,

> +			 0x59, 0x40, 0x3f, 0x3e, 0x41, 0x3d, 0x39, 0x2f,

> +			 0x2c, 0x2b, 0x29, 0x25, 0x29, 0x19, 0x08, 0x00);

> +	mipi_dbi_command(dbi, WS2401_GAMMA_G2, 0x00,

> +			 0x59, 0x40, 0x3f, 0x3e, 0x41, 0x3d, 0x39, 0x2f,

> +			 0x2c, 0x2b, 0x29, 0x25, 0x29, 0x19, 0x08, 0x00);

> +	mipi_dbi_command(dbi, WS2401_GAMMA_B1, 0x00,

> +			 0x57, 0x3b, 0x3a, 0x3b, 0x3f, 0x3b, 0x38, 0x27,

> +			 0x38, 0x2a, 0x26, 0x22, 0x34, 0x0c, 0x09, 0x00);

> +	mipi_dbi_command(dbi, WS2401_GAMMA_B2, 0x00,

> +			 0x57, 0x3b, 0x3a, 0x3b, 0x3f, 0x3b, 0x38, 0x27,

> +			 0x38, 0x2a, 0x26, 0x22, 0x34, 0x0c, 0x09, 0x00);

> +

> +	if (ws->bl) {

> +		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x2c);

> +	} else {

> +		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x00);

> +		/*

> +		 * When not using internal backlight we do not need any further

> +		 * L2 accesses to the panel so we close the door on our way out.

> +		 * Otherwise we need to leave the L2 door open.

> +		 */

> +		mipi_dbi_command(dbi, WS2401_PASSWD1, 0xa5, 0xa5);

> +	}

> +

> +	return 0;

> +}

> +

> +static int ws2401_power_off(struct ws2401 *ws)

> +{

> +	/* Go into RESET and disable regulators */

> +	gpiod_set_value_cansleep(ws->reset, 1);

> +	return regulator_bulk_disable(ARRAY_SIZE(ws->regulators),

> +				      ws->regulators);

> +}

> +

> +static int ws2401_unprepare(struct drm_panel *panel)

> +{

> +	struct ws2401 *ws = to_ws2401(panel);

> +	struct mipi_dbi *dbi = &ws->dbi;

> +

> +	/* Make sure we disable backlight, if any */

> +	if (ws->bl)

> +		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x00);

> +	mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);

> +	msleep(120);

> +	return ws2401_power_off(to_ws2401(panel));

> +}

> +

> +static int ws2401_disable(struct drm_panel *panel)

> +{

> +	struct ws2401 *ws = to_ws2401(panel);

> +	struct mipi_dbi *dbi = &ws->dbi;

> +

> +	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);

> +	msleep(25);

> +

> +	return 0;

> +}

> +

> +static int ws2401_prepare(struct drm_panel *panel)

> +{

> +	return ws2401_power_on(to_ws2401(panel));

> +}

> +

> +static int ws2401_enable(struct drm_panel *panel)

> +{

> +	struct ws2401 *ws = to_ws2401(panel);

> +	struct mipi_dbi *dbi = &ws->dbi;

> +

> +	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);

> +

> +	return 0;

> +}

> +

> +/**

> + * ws2401_get_modes() - return the mode

> + * @panel: the panel to get the mode for

> + * @connector: reference to the central DRM connector control structure

> + */

> +static int ws2401_get_modes(struct drm_panel *panel,

> +			    struct drm_connector *connector)

> +{

> +	struct ws2401 *ws = to_ws2401(panel);

> +	struct drm_display_mode *mode;

> +	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;

> +

> +	/*

> +	 * We just support the LMS380KF01 so far, if we implement more panels

> +	 * this mode, the following connector display_info settings and

> +	 * probably the custom DCS sequences needs to selected based on what

> +	 * the target panel needs.

> +	 */

> +	mode = drm_mode_duplicate(connector->dev, &lms380kf01_480_800_mode);

> +	if (!mode) {

> +		dev_err(ws->dev, "failed to add mode\n");

> +		return -ENOMEM;

> +	}

> +

> +	connector->display_info.bpc = 8;

> +	connector->display_info.width_mm = mode->width_mm;

> +	connector->display_info.height_mm = mode->height_mm;

> +	connector->display_info.bus_flags =

> +		DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;

> +	drm_display_info_set_bus_formats(&connector->display_info,

> +					 &bus_format, 1);

> +

> +	drm_mode_set_name(mode);

> +	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;

> +

> +	drm_mode_probed_add(connector, mode);

> +

> +	return 1;

> +}

> +

> +static const struct drm_panel_funcs ws2401_drm_funcs = {

> +	.disable = ws2401_disable,

> +	.unprepare = ws2401_unprepare,

> +	.prepare = ws2401_prepare,

> +	.enable = ws2401_enable,

> +	.get_modes = ws2401_get_modes,

> +};

> +

> +static int ws2401_set_brightness(struct backlight_device *bl)

> +{

> +	struct ws2401 *ws = bl_get_data(bl);

> +	struct mipi_dbi *dbi = &ws->dbi;

> +	u8 brightness = bl->props.brightness;

Use
	u8 brightness = backlight_get_brightness(bl);


backlight_get_brightness() retunrs an int, but you need an u8 for
mipi_dbi_command().


> +

> +	mipi_dbi_command(dbi, WS2401_WRDISBV, brightness);

> +

> +	return 0;

> +}

The idea is that all backlight handling is done in the update_status
function so enable and disable logic should also be here.
Like this:

	if (backlight_is_blank(bl))
		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x00);
	else
		mipi_dbi_command(dbi, WS2401_WRDISBV, brightness);


> +

> +static const struct backlight_ops ws2401_bl_ops = {

> +	.update_status = ws2401_set_brightness,

> +};

> +

> +static const struct backlight_properties ws2401_bl_props = {

> +	.type = BACKLIGHT_PLATFORM,

> +	.brightness = 120,

> +	.max_brightness = U8_MAX,

> +};

> +

> +static int ws2401_probe(struct spi_device *spi)

> +{

> +	struct device *dev = &spi->dev;

> +	struct ws2401 *ws;

> +	int ret;

> +

> +	ws = devm_kzalloc(dev, sizeof(*ws), GFP_KERNEL);

> +	if (!ws)

> +		return -ENOMEM;

> +	ws->dev = dev;

> +

> +	/*

> +	 * VCI   is the analog voltage supply

> +	 * VCCIO is the digital I/O voltage supply

> +	 */

> +	ws->regulators[0].supply = "vci";

> +	ws->regulators[1].supply = "vccio";

> +	ret = devm_regulator_bulk_get(dev,

> +				      ARRAY_SIZE(ws->regulators),

> +				      ws->regulators);

> +	if (ret)

> +		return dev_err_probe(dev, ret, "failed to get regulators\n");

> +

> +	ws->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);

> +	if (IS_ERR(ws->reset)) {

> +		ret = PTR_ERR(ws->reset);

> +		return dev_err_probe(dev, ret, "no RESET GPIO\n");

> +	}

> +

> +	ret = mipi_dbi_spi_init(spi, &ws->dbi, NULL);

> +	if (ret)

> +		return dev_err_probe(dev, ret, "MIPI DBI init failed\n");

> +	ws->dbi.read_commands = ws2401_dbi_read_commands;

> +

> +	ws2401_power_on(ws);

> +	ws2401_read_mtp_id(ws);

> +	ws2401_power_off(ws);

> +

> +	drm_panel_init(&ws->panel, dev, &ws2401_drm_funcs,

> +		       DRM_MODE_CONNECTOR_DPI);

> +

> +	ret = drm_panel_of_backlight(&ws->panel);

> +	if (ret)

> +		return dev_err_probe(dev, ret,

> +				"failed to get external backlight device\n");

> +

> +	if (!ws->panel.backlight) {

> +		dev_dbg(dev, "no external backlight, using internal backlight\n");

> +		ws->bl = devm_backlight_device_register(dev, "ws2401", dev, ws,

> +				&ws2401_bl_ops, &ws2401_bl_props);

Use ws->panel.backlight here, so you automagically have the calls to
enable and disable backlight.
And then use a simple bool flag to use in ws2401_power_on();


> +		if (IS_ERR(ws->bl))

> +			return dev_err_probe(dev, PTR_ERR(ws->bl),

> +				"failed to register backlight device\n");

> +		ws->panel.backlight = ws->bl;

> +	} else {

> +		dev_dbg(dev, "using external backlight\n");

> +	}

> +

> +	spi_set_drvdata(spi, ws);

> +

> +	drm_panel_add(&ws->panel);

> +	dev_dbg(dev, "added panel\n");

> +

> +	return 0;

> +}

> +

> +static int ws2401_remove(struct spi_device *spi)

> +{

> +	struct ws2401 *ws = spi_get_drvdata(spi);

> +

> +	drm_panel_remove(&ws->panel);

> +	return 0;

> +}

> +

> +/*

> + * Samsung LMS380KF01 is the one instance of this display controller that we

> + * know about, but if more are found, the controller can be parameterized

> + * here and used for other configurations.

> + */

> +static const struct of_device_id ws2401_match[] = {

> +	{ .compatible = "samsung,lms380kf01", },

> +	{},

> +};

> +MODULE_DEVICE_TABLE(of, ws2401_match);

> +

> +static struct spi_driver ws2401_driver = {

> +	.probe		= ws2401_probe,

> +	.remove		= ws2401_remove,

> +	.driver		= {

> +		.name	= "ws2401-panel",

> +		.of_match_table = ws2401_match,

> +	},

> +};

> +module_spi_driver(ws2401_driver);

> +

> +MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");

> +MODULE_DESCRIPTION("Samsung WS2401 panel driver");

> +MODULE_LICENSE("GPL v2");

> -- 

> 2.31.1
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index bd7aff0c120f..10bba4be1678 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5956,6 +5956,13 @@  T:	git git://people.freedesktop.org/~sroland/linux
 F:	drivers/gpu/drm/vmwgfx/
 F:	include/uapi/drm/vmwgfx_drm.h
 
+DRM DRIVER FOR WIDECHIPS WS2401 PANELS
+M:	Linus Walleij <linus.walleij@linaro.org>
+S:	Maintained
+T:	git git://anongit.freedesktop.org/drm/drm-misc
+F:	Documentation/devicetree/bindings/display/panel/samsung,lms380kf01.yaml
+F:	drivers/gpu/drm/panel/panel-widechips-ws2401.c
+
 DRM DRIVERS
 M:	David Airlie <airlied@linux.ie>
 M:	Daniel Vetter <daniel@ffwll.ch>
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index 4894913936e9..319fa44c4bc9 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -552,6 +552,15 @@  config DRM_PANEL_VISIONOX_RM69299
 	  Say Y here if you want to enable support for Visionox
 	  RM69299  DSI Video Mode panel.
 
+config DRM_PANEL_WIDECHIPS_WS2401
+	tristate "Widechips WS2401 DPI panel driver"
+	depends on SPI && GPIOLIB
+	depends on BACKLIGHT_CLASS_DEVICE
+	select DRM_MIPI_DBI
+	help
+	  Say Y here if you want to enable support for the Widechips WS2401 DPI
+	  480x800 display controller used in panels such as Samsung LMS380KF01.
+
 config DRM_PANEL_XINPENG_XPP055C272
 	tristate "Xinpeng XPP055C272 panel driver"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index cae4d976c069..d94c27df17aa 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -58,4 +58,5 @@  obj-$(CONFIG_DRM_PANEL_TPO_TD043MTEA1) += panel-tpo-td043mtea1.o
 obj-$(CONFIG_DRM_PANEL_TPO_TPG110) += panel-tpo-tpg110.o
 obj-$(CONFIG_DRM_PANEL_TRULY_NT35597_WQXGA) += panel-truly-nt35597.o
 obj-$(CONFIG_DRM_PANEL_VISIONOX_RM69299) += panel-visionox-rm69299.o
+obj-$(CONFIG_DRM_PANEL_WIDECHIPS_WS2401) += panel-widechips-ws2401.o
 obj-$(CONFIG_DRM_PANEL_XINPENG_XPP055C272) += panel-xinpeng-xpp055c272.o
diff --git a/drivers/gpu/drm/panel/panel-widechips-ws2401.c b/drivers/gpu/drm/panel/panel-widechips-ws2401.c
new file mode 100644
index 000000000000..95825063f812
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-widechips-ws2401.c
@@ -0,0 +1,436 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Panel driver for the WideChips WS2401 480x800 DPI RGB panel, used in
+ * the Samsung Mobile Display (SMD) LMS380KF01.
+ * Found in the Samsung Galaxy Ace 2 GT-I8160 mobile phone.
+ * Linus Walleij <linus.walleij@linaro.org>
+ * Inspired by code and know-how in the vendor driver by Gareth Phillips.
+ */
+#include <drm/drm_mipi_dbi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_panel.h>
+
+#include <linux/backlight.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/media-bus-format.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <video/mipi_display.h>
+
+#define WS2401_RESCTL			0xb8 /* Resolution select control */
+#define WS2401_PSMPS			0xbd /* SMPS positive control */
+#define WS2401_NSMPS			0xbe /* SMPS negative control */
+#define WS2401_SMPS			0xbf
+#define WS2401_BCMODE			0xc1 /* Backlight control mode */
+#define WS2401_WRBLCTL			0xc3 /* Backlight control */
+#define WS2401_WRDISBV			0xc4 /* Write manual brightness */
+#define WS2401_WRCTRLD			0xc6 /* Write BL control */
+#define WS2401_WRMIE			0xc7 /* Write MIE mode */
+#define WS2401_READ_ID1			0xda /* Read panel ID 1 */
+#define WS2401_READ_ID2			0xdb /* Read panel ID 2 */
+#define WS2401_READ_ID3			0xdc /* Read panel ID 3 */
+#define WS2401_GAMMA_R1			0xe7 /* Gamma red 1 */
+#define WS2401_GAMMA_G1			0xe8 /* Gamma green 1 */
+#define WS2401_GAMMA_B1			0xe9 /* Gamma blue 1 */
+#define WS2401_GAMMA_R2			0xea /* Gamma red 2 */
+#define WS2401_GAMMA_G2			0xeb /* Gamma green 2 */
+#define WS2401_GAMMA_B2			0xec /* Gamma blue 2 */
+#define WS2401_PASSWD1			0xf0 /* Password command for level 2 */
+#define WS2401_DISCTL			0xf2 /* Display control */
+#define WS2401_PWRCTL			0xf3 /* Power control */
+#define WS2401_VCOMCTL			0xf4 /* VCOM control */
+#define WS2401_SRCCTL			0xf5 /* Source control */
+#define WS2401_PANELCTL			0xf6 /* Panel control */
+
+static const u8 ws2401_dbi_read_commands[] = {
+	WS2401_READ_ID1,
+	WS2401_READ_ID2,
+	WS2401_READ_ID3,
+	0, /* sentinel */
+};
+
+/**
+ * struct ws2401 - state container for a panel controlled by the WS2401
+ * controller
+ */
+struct ws2401 {
+	/** @dev: the container device */
+	struct device *dev;
+	/** @dbi: the DBI bus abstraction handle */
+	struct mipi_dbi dbi;
+	/** @panel: the DRM panel instance for this device */
+	struct drm_panel panel;
+	/** @width: the width of this panel in mm */
+	u32 width;
+	/** @height: the height of this panel in mm */
+	u32 height;
+	/** @reset: reset GPIO line */
+	struct gpio_desc *reset;
+	/** @regulators: VCCIO and VIO supply regulators */
+	struct regulator_bulk_data regulators[2];
+	/** @bl: Backlight, if using internal backlight */
+	struct backlight_device *bl;
+};
+
+static const struct drm_display_mode lms380kf01_480_800_mode = {
+	/*
+	 * The vendor driver states that the "SMD panel" has a clock
+	 * frequency of 49920000 Hz / 2 = 24960000 Hz.
+	 */
+	.clock = 24960,
+	.hdisplay = 480,
+	.hsync_start = 480 + 8,
+	.hsync_end = 480 + 8 + 10,
+	.htotal = 480 + 8 + 10 + 8,
+	.vdisplay = 800,
+	.vsync_start = 800 + 8,
+	.vsync_end = 800 + 8 + 2,
+	.vtotal = 800 + 8 + 2 + 18,
+	.width_mm = 50,
+	.height_mm = 84,
+	.flags = DRM_MODE_FLAG_NVSYNC | DRM_MODE_FLAG_NHSYNC,
+};
+
+static inline struct ws2401 *to_ws2401(struct drm_panel *panel)
+{
+	return container_of(panel, struct ws2401, panel);
+}
+
+static void ws2401_read_mtp_id(struct ws2401 *ws)
+{
+	struct mipi_dbi *dbi = &ws->dbi;
+	u8 id1, id2, id3;
+	int ret;
+
+	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID1, &id1);
+	if (ret) {
+		dev_err(ws->dev, "unable to read MTP ID 1\n");
+		return;
+	}
+	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID2, &id2);
+	if (ret) {
+		dev_err(ws->dev, "unable to read MTP ID 2\n");
+		return;
+	}
+	ret = mipi_dbi_command_read(dbi, WS2401_READ_ID3, &id3);
+	if (ret) {
+		dev_err(ws->dev, "unable to read MTP ID 3\n");
+		return;
+	}
+	dev_info(ws->dev, "MTP ID: %02x %02x %02x\n", id1, id2, id3);
+}
+
+static int ws2401_power_on(struct ws2401 *ws)
+{
+	struct mipi_dbi *dbi = &ws->dbi;
+	int ret;
+
+	/* Power up */
+	ret = regulator_bulk_enable(ARRAY_SIZE(ws->regulators),
+				    ws->regulators);
+	if (ret) {
+		dev_err(ws->dev, "failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+	msleep(10);
+
+	/* Assert reset >=1 ms */
+	gpiod_set_value_cansleep(ws->reset, 1);
+	usleep_range(1000, 5000);
+	/* De-assert reset */
+	gpiod_set_value_cansleep(ws->reset, 0);
+	/* Wait >= 10 ms */
+	msleep(10);
+	dev_dbg(ws->dev, "de-asserted RESET\n");
+
+	/*
+	 * Exit sleep mode and initialize display - some hammering is
+	 * necessary.
+	 */
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	msleep(50);
+
+	/* Magic to unlock level 2 control of the display */
+	mipi_dbi_command(dbi, WS2401_PASSWD1, 0x5a, 0x5a);
+	/* Configure resolution to 480RGBx800 */
+	mipi_dbi_command(dbi, WS2401_RESCTL, 0x12);
+	/* Set addressing mode Flip V(d0), Flip H(d1) RGB/BGR(d3) */
+	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, 0x01);
+	/* Set pixel format: 24 bpp */
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, 0x70);
+	mipi_dbi_command(dbi, WS2401_SMPS, 0x00, 0x0f);
+	mipi_dbi_command(dbi, WS2401_PSMPS, 0x06, 0x03, /* DDVDH: 4.6v */
+			 0x7e, 0x03, 0x12, 0x37);
+	mipi_dbi_command(dbi, WS2401_NSMPS, 0x06, 0x03, /* DDVDH: -4.6v */
+			 0x7e, 0x02, 0x15, 0x37);
+	mipi_dbi_command(dbi, WS2401_SMPS, 0x02, 0x0f);
+	mipi_dbi_command(dbi, WS2401_PWRCTL, 0x10, 0xA9, 0x00, 0x01, 0x44,
+			 0xb4,	/* VGH:16.1v, VGL:-13.8v */
+			 0x50,	/* GREFP:4.2v (default) */
+			 0x50,	/* GREFN:-4.2v (default) */
+			 0x00,
+			 0x44);	/* VOUTL:-10v (default) */
+	mipi_dbi_command(dbi, WS2401_DISCTL, 0x01, 0x00, 0x00, 0x00, 0x14,
+			 0x16);
+	mipi_dbi_command(dbi, WS2401_VCOMCTL, 0x30, 0x53, 0x53);
+	mipi_dbi_command(dbi, WS2401_SRCCTL, 0x03, 0x0C, 0x00, 0x00, 0x00,
+			 0x01,	/* 2 dot inversion */
+			 0x01, 0x06, 0x03);
+	mipi_dbi_command(dbi, WS2401_PANELCTL, 0x14, 0x00, 0x80, 0x00);
+	mipi_dbi_command(dbi, WS2401_WRMIE, 0x01);
+
+	/* Set up gamma, probably these are P-gamma and N-gamma for each color */
+	mipi_dbi_command(dbi, WS2401_GAMMA_R1, 0x00,
+			 0x5b, 0x42, 0x41, 0x3f, 0x42, 0x3d, 0x38, 0x2e,
+			 0x2b, 0x2a, 0x27, 0x22, 0x27, 0x0f, 0x00, 0x00);
+	mipi_dbi_command(dbi, WS2401_GAMMA_R2, 0x00,
+			 0x5b, 0x42, 0x41, 0x3f, 0x42, 0x3d, 0x38, 0x2e,
+			 0x2b, 0x2a, 0x27, 0x22, 0x27, 0x0f, 0x00, 0x00);
+	mipi_dbi_command(dbi, WS2401_GAMMA_G1, 0x00,
+			 0x59, 0x40, 0x3f, 0x3e, 0x41, 0x3d, 0x39, 0x2f,
+			 0x2c, 0x2b, 0x29, 0x25, 0x29, 0x19, 0x08, 0x00);
+	mipi_dbi_command(dbi, WS2401_GAMMA_G2, 0x00,
+			 0x59, 0x40, 0x3f, 0x3e, 0x41, 0x3d, 0x39, 0x2f,
+			 0x2c, 0x2b, 0x29, 0x25, 0x29, 0x19, 0x08, 0x00);
+	mipi_dbi_command(dbi, WS2401_GAMMA_B1, 0x00,
+			 0x57, 0x3b, 0x3a, 0x3b, 0x3f, 0x3b, 0x38, 0x27,
+			 0x38, 0x2a, 0x26, 0x22, 0x34, 0x0c, 0x09, 0x00);
+	mipi_dbi_command(dbi, WS2401_GAMMA_B2, 0x00,
+			 0x57, 0x3b, 0x3a, 0x3b, 0x3f, 0x3b, 0x38, 0x27,
+			 0x38, 0x2a, 0x26, 0x22, 0x34, 0x0c, 0x09, 0x00);
+
+	if (ws->bl) {
+		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x2c);
+	} else {
+		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x00);
+		/*
+		 * When not using internal backlight we do not need any further
+		 * L2 accesses to the panel so we close the door on our way out.
+		 * Otherwise we need to leave the L2 door open.
+		 */
+		mipi_dbi_command(dbi, WS2401_PASSWD1, 0xa5, 0xa5);
+	}
+
+	return 0;
+}
+
+static int ws2401_power_off(struct ws2401 *ws)
+{
+	/* Go into RESET and disable regulators */
+	gpiod_set_value_cansleep(ws->reset, 1);
+	return regulator_bulk_disable(ARRAY_SIZE(ws->regulators),
+				      ws->regulators);
+}
+
+static int ws2401_unprepare(struct drm_panel *panel)
+{
+	struct ws2401 *ws = to_ws2401(panel);
+	struct mipi_dbi *dbi = &ws->dbi;
+
+	/* Make sure we disable backlight, if any */
+	if (ws->bl)
+		mipi_dbi_command(dbi, WS2401_WRCTRLD, 0x00);
+	mipi_dbi_command(dbi, MIPI_DCS_ENTER_SLEEP_MODE);
+	msleep(120);
+	return ws2401_power_off(to_ws2401(panel));
+}
+
+static int ws2401_disable(struct drm_panel *panel)
+{
+	struct ws2401 *ws = to_ws2401(panel);
+	struct mipi_dbi *dbi = &ws->dbi;
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
+	msleep(25);
+
+	return 0;
+}
+
+static int ws2401_prepare(struct drm_panel *panel)
+{
+	return ws2401_power_on(to_ws2401(panel));
+}
+
+static int ws2401_enable(struct drm_panel *panel)
+{
+	struct ws2401 *ws = to_ws2401(panel);
+	struct mipi_dbi *dbi = &ws->dbi;
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+
+	return 0;
+}
+
+/**
+ * ws2401_get_modes() - return the mode
+ * @panel: the panel to get the mode for
+ * @connector: reference to the central DRM connector control structure
+ */
+static int ws2401_get_modes(struct drm_panel *panel,
+			    struct drm_connector *connector)
+{
+	struct ws2401 *ws = to_ws2401(panel);
+	struct drm_display_mode *mode;
+	static const u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+
+	/*
+	 * We just support the LMS380KF01 so far, if we implement more panels
+	 * this mode, the following connector display_info settings and
+	 * probably the custom DCS sequences needs to selected based on what
+	 * the target panel needs.
+	 */
+	mode = drm_mode_duplicate(connector->dev, &lms380kf01_480_800_mode);
+	if (!mode) {
+		dev_err(ws->dev, "failed to add mode\n");
+		return -ENOMEM;
+	}
+
+	connector->display_info.bpc = 8;
+	connector->display_info.width_mm = mode->width_mm;
+	connector->display_info.height_mm = mode->height_mm;
+	connector->display_info.bus_flags =
+		DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE;
+	drm_display_info_set_bus_formats(&connector->display_info,
+					 &bus_format, 1);
+
+	drm_mode_set_name(mode);
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+
+	drm_mode_probed_add(connector, mode);
+
+	return 1;
+}
+
+static const struct drm_panel_funcs ws2401_drm_funcs = {
+	.disable = ws2401_disable,
+	.unprepare = ws2401_unprepare,
+	.prepare = ws2401_prepare,
+	.enable = ws2401_enable,
+	.get_modes = ws2401_get_modes,
+};
+
+static int ws2401_set_brightness(struct backlight_device *bl)
+{
+	struct ws2401 *ws = bl_get_data(bl);
+	struct mipi_dbi *dbi = &ws->dbi;
+	u8 brightness = bl->props.brightness;
+
+	mipi_dbi_command(dbi, WS2401_WRDISBV, brightness);
+
+	return 0;
+}
+
+static const struct backlight_ops ws2401_bl_ops = {
+	.update_status = ws2401_set_brightness,
+};
+
+static const struct backlight_properties ws2401_bl_props = {
+	.type = BACKLIGHT_PLATFORM,
+	.brightness = 120,
+	.max_brightness = U8_MAX,
+};
+
+static int ws2401_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct ws2401 *ws;
+	int ret;
+
+	ws = devm_kzalloc(dev, sizeof(*ws), GFP_KERNEL);
+	if (!ws)
+		return -ENOMEM;
+	ws->dev = dev;
+
+	/*
+	 * VCI   is the analog voltage supply
+	 * VCCIO is the digital I/O voltage supply
+	 */
+	ws->regulators[0].supply = "vci";
+	ws->regulators[1].supply = "vccio";
+	ret = devm_regulator_bulk_get(dev,
+				      ARRAY_SIZE(ws->regulators),
+				      ws->regulators);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to get regulators\n");
+
+	ws->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(ws->reset)) {
+		ret = PTR_ERR(ws->reset);
+		return dev_err_probe(dev, ret, "no RESET GPIO\n");
+	}
+
+	ret = mipi_dbi_spi_init(spi, &ws->dbi, NULL);
+	if (ret)
+		return dev_err_probe(dev, ret, "MIPI DBI init failed\n");
+	ws->dbi.read_commands = ws2401_dbi_read_commands;
+
+	ws2401_power_on(ws);
+	ws2401_read_mtp_id(ws);
+	ws2401_power_off(ws);
+
+	drm_panel_init(&ws->panel, dev, &ws2401_drm_funcs,
+		       DRM_MODE_CONNECTOR_DPI);
+
+	ret = drm_panel_of_backlight(&ws->panel);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				"failed to get external backlight device\n");
+
+	if (!ws->panel.backlight) {
+		dev_dbg(dev, "no external backlight, using internal backlight\n");
+		ws->bl = devm_backlight_device_register(dev, "ws2401", dev, ws,
+				&ws2401_bl_ops, &ws2401_bl_props);
+		if (IS_ERR(ws->bl))
+			return dev_err_probe(dev, PTR_ERR(ws->bl),
+				"failed to register backlight device\n");
+		ws->panel.backlight = ws->bl;
+	} else {
+		dev_dbg(dev, "using external backlight\n");
+	}
+
+	spi_set_drvdata(spi, ws);
+
+	drm_panel_add(&ws->panel);
+	dev_dbg(dev, "added panel\n");
+
+	return 0;
+}
+
+static int ws2401_remove(struct spi_device *spi)
+{
+	struct ws2401 *ws = spi_get_drvdata(spi);
+
+	drm_panel_remove(&ws->panel);
+	return 0;
+}
+
+/*
+ * Samsung LMS380KF01 is the one instance of this display controller that we
+ * know about, but if more are found, the controller can be parameterized
+ * here and used for other configurations.
+ */
+static const struct of_device_id ws2401_match[] = {
+	{ .compatible = "samsung,lms380kf01", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ws2401_match);
+
+static struct spi_driver ws2401_driver = {
+	.probe		= ws2401_probe,
+	.remove		= ws2401_remove,
+	.driver		= {
+		.name	= "ws2401-panel",
+		.of_match_table = ws2401_match,
+	},
+};
+module_spi_driver(ws2401_driver);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("Samsung WS2401 panel driver");
+MODULE_LICENSE("GPL v2");