diff mbox series

[v6,03/12] pinctrl: Add MAX7360 pinctrl driver

Message ID 20250409-mdb-max7360-support-v6-3-7a2535876e39@bootlin.com
State New
Headers show
Series Add support for MAX7360 | expand

Commit Message

Mathieu Dubois-Briand April 9, 2025, 2:55 p.m. UTC
Add driver for Maxim Integrated MAX7360 pinctrl on the PORT pins. Pins
can be used either for GPIO, PWM or rotary encoder functionalities.

Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/pinctrl/Kconfig           |  11 ++
 drivers/pinctrl/Makefile          |   1 +
 drivers/pinctrl/pinctrl-max7360.c | 208 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 220 insertions(+)

Comments

Mathieu Dubois-Briand April 10, 2025, 8:37 a.m. UTC | #1
On Wed Apr 9, 2025 at 6:32 PM CEST, Andy Shevchenko wrote:
> On Wed, Apr 09, 2025 at 05:03:02PM +0200, Mathieu Dubois-Briand wrote:
>> On Wed Apr 9, 2025 at 4:55 PM CEST, Mathieu Dubois-Briand wrote:
>> > Add driver for Maxim Integrated MAX7360 pinctrl on the PORT pins. Pins
>> > can be used either for GPIO, PWM or rotary encoder functionalities.
>
> ...
>
> The all the rest of the driver LGTM, but the below.
>
>> > +	device_set_of_node_from_dev(dev, dev->parent);
>> 
>> Ok, so this goes a bit against what I said I was going to do on my
>> previous series, let me explain why. Same reasoning applies for both
>> uses, in PWM and pinctrl drivers.
>> 
>> With my previous experiments, I came to the conclusion that:
>> - Either we should use device_set_of_node_from_dev() as I do here.
>> - Or we should add more subnodes in the device tree binding.
>
>> - Also, copying the fwnode with device_set_node() was not possible, as
>>   the kernel would then try to apply pinctrl on both the parent and
>>   child device.
>
> Hmm... I need to refresh my memory with the old discussions. Can you point out
> to the problem statement with that approach?
>

I mentioned here briefly in my previous series: https://lore.kernel.org/lkml/D8R4B2PKIWSU.2LWTN50YP7SMX@bootlin.com/

So the issue is, if I copy the parent fwnode using device_set_node(),
the kernel is trying to apply any pinctrl defined on the node with
pinctrl- properties on both the parent and the child node. Of course,
only the first one will succeed, as two devices cannot request the same
pins at the same time.

>> I previously said the second solution was probably the way to go, but I
>> changed my mind for two reasons.
>> 
>> First having more subnodes in the device tree was already rejected in
>> the past in the reviews of the dt-bindings patch. This do makes sense as
>> it would be describing device internals (which should not be made in
>> DT), just to ease one specific software implementation (which should
>> also be avoided). So I believe this change would again be rejected.
>> https://lore.kernel.org/lkml/58c80c2a-2532-4bc5-9c9f-52480b3af52a@kernel.org/
>> 
>> But the the second reason is, doing
>> 'git grep "device_set_of_node_from_dev.*parent"', I found several
>> drivers using device_set_of_node_from_dev() for a similar need. Some of
>> these uses are also for MFD child devices:
>> - gpio-adp5585.c / pwm-adp5585.c,
>> - pwm-ntxec.c,
>> - max77620-regulator.c / max77620_thermal.c.
>> 
>> So, based on this, I believe using device_set_of_node_from_dev() in
>> these two drivers is the way to go.
>
> The problem with this solution is that, It's OF-centric. Which shouldn't be
> done in a new code (and I don't see impediments to avoid it). Yes, it does
> the right thing for the case, but only on OF systems. Note, fwnode is a list
> of maximum of two entries (yeah, designed like that right now), can you utilise
> that somehow?

Looking at MFD code, I believe ACPI MFD child devices already get the
parent fwnode, except if a fwnode exists for them.

https://elixir.bootlin.com/linux/v6.13.7/source/drivers/mfd/mfd-core.c#L90

Thanks for your review.
diff mbox series

Patch

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index 464cc9aca157..276695c7a92e 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -348,6 +348,17 @@  config PINCTRL_LPC18XX
 	help
 	  Pinctrl driver for NXP LPC18xx/43xx System Control Unit (SCU).
 
+config PINCTRL_MAX7360
+	tristate "MAX7360 Pincontrol support"
+	depends on MFD_MAX7360
+	select PINMUX
+	select GENERIC_PINCONF
+	help
+	  Say Y here to enable pin control support for Maxim MAX7360 keypad
+	  controller.
+	  This keypad controller has 8 GPIO pins that may work as GPIO, or PWM,
+	  or rotary encoder alternate modes.
+
 config PINCTRL_MAX77620
 	tristate "MAX77620/MAX20024 Pincontrol support"
 	depends on MFD_MAX77620 && OF
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index ac27e88677d1..974a179b5593 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -36,6 +36,7 @@  obj-$(CONFIG_PINCTRL_FALCON)	+= pinctrl-falcon.o
 obj-$(CONFIG_PINCTRL_LOONGSON2) += pinctrl-loongson2.o
 obj-$(CONFIG_PINCTRL_XWAY)	+= pinctrl-xway.o
 obj-$(CONFIG_PINCTRL_LPC18XX)	+= pinctrl-lpc18xx.o
+obj-$(CONFIG_PINCTRL_MAX7360)	+= pinctrl-max7360.o
 obj-$(CONFIG_PINCTRL_MAX77620)	+= pinctrl-max77620.o
 obj-$(CONFIG_PINCTRL_MCP23S08_I2C)	+= pinctrl-mcp23s08_i2c.o
 obj-$(CONFIG_PINCTRL_MCP23S08_SPI)	+= pinctrl-mcp23s08_spi.o
diff --git a/drivers/pinctrl/pinctrl-max7360.c b/drivers/pinctrl/pinctrl-max7360.c
new file mode 100644
index 000000000000..ebd98666cd39
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-max7360.c
@@ -0,0 +1,208 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Bootlin
+ *
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/array_size.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/device/devres.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/mfd/max7360.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinmux.h>
+
+#include "core.h"
+#include "pinmux.h"
+
+struct max7360_pinctrl {
+	struct pinctrl_dev *pctldev;
+	struct pinctrl_desc pinctrl_desc;
+};
+
+static const struct pinctrl_pin_desc max7360_pins[] = {
+	PINCTRL_PIN(0, "PORT0"),
+	PINCTRL_PIN(1, "PORT1"),
+	PINCTRL_PIN(2, "PORT2"),
+	PINCTRL_PIN(3, "PORT3"),
+	PINCTRL_PIN(4, "PORT4"),
+	PINCTRL_PIN(5, "PORT5"),
+	PINCTRL_PIN(6, "PORT6"),
+	PINCTRL_PIN(7, "PORT7"),
+};
+
+static const unsigned int port0_pins[] = {0};
+static const unsigned int port1_pins[] = {1};
+static const unsigned int port2_pins[] = {2};
+static const unsigned int port3_pins[] = {3};
+static const unsigned int port4_pins[] = {4};
+static const unsigned int port5_pins[] = {5};
+static const unsigned int port6_pins[] = {6};
+static const unsigned int port7_pins[] = {7};
+static const unsigned int rotary_pins[] = {6, 7};
+
+static const struct pingroup max7360_groups[] = {
+	PINCTRL_PINGROUP("PORT0", port0_pins, ARRAY_SIZE(port0_pins)),
+	PINCTRL_PINGROUP("PORT1", port1_pins, ARRAY_SIZE(port1_pins)),
+	PINCTRL_PINGROUP("PORT2", port2_pins, ARRAY_SIZE(port2_pins)),
+	PINCTRL_PINGROUP("PORT3", port3_pins, ARRAY_SIZE(port3_pins)),
+	PINCTRL_PINGROUP("PORT4", port4_pins, ARRAY_SIZE(port4_pins)),
+	PINCTRL_PINGROUP("PORT5", port5_pins, ARRAY_SIZE(port5_pins)),
+	PINCTRL_PINGROUP("PORT6", port6_pins, ARRAY_SIZE(port6_pins)),
+	PINCTRL_PINGROUP("PORT7", port7_pins, ARRAY_SIZE(port7_pins)),
+	PINCTRL_PINGROUP("ROTARY", rotary_pins, ARRAY_SIZE(rotary_pins)),
+};
+
+static int max7360_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(max7360_groups);
+}
+
+static const char *max7360_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
+						  unsigned int group)
+{
+	return max7360_groups[group].name;
+}
+
+static int max7360_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
+					  unsigned int group,
+					  const unsigned int **pins,
+					  unsigned int *num_pins)
+{
+	*pins = max7360_groups[group].pins;
+	*num_pins = max7360_groups[group].npins;
+	return 0;
+}
+
+static const struct pinctrl_ops max7360_pinctrl_ops = {
+	.get_groups_count = max7360_pinctrl_get_groups_count,
+	.get_group_name = max7360_pinctrl_get_group_name,
+	.get_group_pins = max7360_pinctrl_get_group_pins,
+#ifdef CONFIG_OF
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
+	.dt_free_map = pinconf_generic_dt_free_map,
+#endif
+};
+
+static const char * const simple_groups[] = {
+	"PORT0", "PORT1", "PORT2", "PORT3",
+	"PORT4", "PORT5", "PORT6", "PORT7",
+};
+
+static const char * const rotary_groups[] = { "ROTARY" };
+
+#define MAX7360_PINCTRL_FN_GPIO		0
+#define MAX7360_PINCTRL_FN_PWM		1
+#define MAX7360_PINCTRL_FN_ROTARY	2
+static const struct pinfunction max7360_functions[] = {
+	[MAX7360_PINCTRL_FN_GPIO] = PINCTRL_PINFUNCTION("gpio", simple_groups,
+							ARRAY_SIZE(simple_groups)),
+	[MAX7360_PINCTRL_FN_PWM] = PINCTRL_PINFUNCTION("pwm", simple_groups,
+						       ARRAY_SIZE(simple_groups)),
+	[MAX7360_PINCTRL_FN_ROTARY] = PINCTRL_PINFUNCTION("rotary", rotary_groups,
+							  ARRAY_SIZE(rotary_groups)),
+};
+
+static int max7360_get_functions_count(struct pinctrl_dev *pctldev)
+{
+	return ARRAY_SIZE(max7360_functions);
+}
+
+static const char *max7360_get_function_name(struct pinctrl_dev *pctldev, unsigned int selector)
+{
+	return max7360_functions[selector].name;
+}
+
+static int max7360_get_function_groups(struct pinctrl_dev *pctldev, unsigned int selector,
+				       const char * const **groups,
+				       unsigned int * const num_groups)
+{
+	*groups = max7360_functions[selector].groups;
+	*num_groups = max7360_functions[selector].ngroups;
+
+	return 0;
+}
+
+static int max7360_set_mux(struct pinctrl_dev *pctldev, unsigned int selector,
+			   unsigned int group)
+{
+	struct regmap *regmap;
+	int val;
+
+	/*
+	 * GPIO and PWM functions are the same: we only need to handle the
+	 * rotary encoder function, on pins 6 and 7.
+	 */
+	if (max7360_groups[group].pins[0] >= 6) {
+		if (selector == MAX7360_PINCTRL_FN_ROTARY)
+			val = MAX7360_GPIO_CFG_RTR_EN;
+		else
+			val = 0;
+
+		regmap = dev_get_regmap(pctldev->dev->parent, NULL);
+		return regmap_write_bits(regmap, MAX7360_REG_GPIOCFG, MAX7360_GPIO_CFG_RTR_EN, val);
+	}
+
+	return 0;
+}
+
+static const struct pinmux_ops max7360_pmxops = {
+	.get_functions_count = max7360_get_functions_count,
+	.get_function_name = max7360_get_function_name,
+	.get_function_groups = max7360_get_function_groups,
+	.set_mux = max7360_set_mux,
+	.strict = true,
+};
+
+static int max7360_pinctrl_probe(struct platform_device *pdev)
+{
+	struct regmap *regmap;
+	struct pinctrl_desc *pd;
+	struct max7360_pinctrl *chip;
+	struct device *dev = &pdev->dev;
+
+	regmap = dev_get_regmap(dev->parent, NULL);
+	if (!regmap)
+		dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	pd = &chip->pinctrl_desc;
+
+	pd->pctlops = &max7360_pinctrl_ops;
+	pd->pmxops = &max7360_pmxops;
+	pd->name = dev_name(dev);
+	pd->pins = max7360_pins;
+	pd->npins = MAX7360_MAX_GPIO;
+	pd->owner = THIS_MODULE;
+
+	device_set_of_node_from_dev(dev, dev->parent);
+	chip->pctldev = devm_pinctrl_register(dev, pd, chip);
+	if (IS_ERR(chip->pctldev))
+		return dev_err_probe(dev, PTR_ERR(chip->pctldev), "can't register controller\n");
+
+	return 0;
+}
+
+static struct platform_driver max7360_pinctrl_driver = {
+	.driver = {
+		.name	= "max7360-pinctrl",
+	},
+	.probe		= max7360_pinctrl_probe,
+};
+module_platform_driver(max7360_pinctrl_driver);
+
+MODULE_DESCRIPTION("MAX7360 pinctrl driver");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");