[v4,62/80] drm/omap: dsi: simplify VC handling

The VC handling has gotten quite tangled up. As the first step to clean
it up, lets define that we only support a single DSI peripheral (which
was really already the case), and we always use VC0 (define VC_DEFAULT
0) register block to send data to the peripheral.

We can thus have a single mipi_dsi_device pointer and remove the for
loops which made passes over all the four VCs (just the first one was
ever used).

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
---
 drivers/gpu/drm/omapdrm/dss/dsi.c | 49 ++++++++-----------------------
 1 file changed, 13 insertions(+), 36 deletions(-)

Hi Tomi,

Thank you for the patch.

On Tue, Nov 24, 2020 at 02:45:20PM +0200, Tomi Valkeinen wrote:
> The VC handling has gotten quite tangled up. As the first step to clean
> it up, lets define that we only support a single DSI peripheral (which
> was really already the case), and we always use VC0 (define VC_DEFAULT
> 0) register block to send data to the peripheral.
> 
> We can thus have a single mipi_dsi_device pointer and remove the for

s/the for/the need for/ ?

> loops which made passes over all the four VCs (just the first one was
> ever used).
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/gpu/drm/omapdrm/dss/dsi.c | 49 ++++++++-----------------------
>  1 file changed, 13 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index 746c2149fbbd..63338324c564 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -360,9 +360,10 @@ struct dsi_data {
>  	bool vdds_dsi_enabled;
>  	struct regulator *vdds_dsi_reg;
>  
> +	struct mipi_dsi_device *dsidev;
> +
>  	struct {
>  		enum dsi_vc_source source;
> -		struct mipi_dsi_device *dest;
>  		enum fifo_size tx_fifo_size;
>  		enum fifo_size rx_fifo_size;
>  	} vc[4];
> @@ -452,6 +453,8 @@ static bool dsi_perf;
>  module_param(dsi_perf, bool, 0644);
>  #endif
>  
> +#define VC_DEFAULT 0
> +
>  #define drm_bridge_to_dsi(bridge) \
>  	container_of(bridge, struct dsi_data, bridge)
>  
> @@ -3716,16 +3719,11 @@ static void dsi_disable_video_output(struct omap_dss_device *dssdev, int channel
>  static void dsi_disable_video_outputs(struct omap_dss_device *dssdev)
>  {
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
> -	unsigned int i;
>  
>  	dsi_bus_lock(dsi);
>  	dsi->video_enabled = false;
>  
> -	for (i = 0; i < 4; i++) {
> -		if (!dsi->vc[i].dest)
> -			continue;
> -		dsi_disable_video_output(dssdev, i);
> -	}
> +	dsi_disable_video_output(dssdev, VC_DEFAULT);
>  
>  	dsi_display_disable(dssdev);
>  
> @@ -3914,11 +3912,6 @@ static int dsi_update_channel(struct omap_dss_device *dssdev, int channel)
>  		goto err;
>  	}
>  
> -	if (!dsi->vc[channel].dest) {
> -		r = -ENODEV;
> -		goto err;
> -	}
> -
>  	if (dsi->vm.hactive == 0 || dsi->vm.vactive == 0) {
>  		r = -EINVAL;
>  		goto err;
> @@ -3954,16 +3947,7 @@ static int dsi_update_channel(struct omap_dss_device *dssdev, int channel)
>  
>  static int dsi_update_all(struct omap_dss_device *dssdev)
>  {
> -	unsigned int i;
> -	int r;
> -
> -	for (i = 0; i < 4; i++) {
> -		r = dsi_update_channel(dssdev, i);
> -		if (r && r != -ENODEV)
> -			return r;
> -	}
> -
> -	return r;
> +	return dsi_update_channel(dssdev, VC_DEFAULT);
>  }
>  
>  /* Display funcs */
> @@ -4191,17 +4175,12 @@ static void dsi_display_enable(struct omap_dss_device *dssdev)
>  static void dsi_enable_video_outputs(struct omap_dss_device *dssdev)
>  {
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
> -	unsigned int i;
>  
>  	dsi_bus_lock(dsi);
>  
>  	dsi_display_enable(dssdev);
>  
> -	for (i = 0; i < 4; i++) {
> -		if (!dsi->vc[i].dest)
> -			continue;
> -		dsi_enable_video_output(dssdev, i);
> -	}
> +	dsi_enable_video_output(dssdev, VC_DEFAULT);
>  
>  	dsi->video_enabled = true;
>  
> @@ -5090,8 +5069,8 @@ static int omap_dsi_host_attach(struct mipi_dsi_host *host,
>  	if (channel > 3)
>  		return -EINVAL;
>  
> -	if (dsi->vc[channel].dest) {
> -		DSSERR("cannot get VC for display %s", dev_name(&client->dev));
> +	if (dsi->dsidev) {
> +		DSSERR("dsi client already attached\n");
>  		return -EBUSY;
>  	}
>  
> @@ -5112,7 +5091,7 @@ static int omap_dsi_host_attach(struct mipi_dsi_host *host,
>  		dsi->mode = OMAP_DSS_DSI_CMD_MODE;
>  	}
>  
> -	dsi->vc[channel].dest = client;
> +	dsi->dsidev = client;
>  	dsi->pix_fmt = client->format;
>  
>  	INIT_DEFERRABLE_WORK(&dsi->ulps_work,
> @@ -5144,11 +5123,11 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
>  	if (channel > 3)
>  		return -EINVAL;
>  
> -	if (dsi->vc[channel].dest != client)
> +	if (WARN_ON(dsi->dsidev != client))
>  		return -EINVAL;
>  
>  	omap_dsi_unregister_te_irq(dsi);
> -	dsi->vc[channel].dest = NULL;
> +	dsi->dsidev = NULL;
>  	return 0;
>  }
>  
> @@ -5680,10 +5659,8 @@ static int dsi_probe(struct platform_device *pdev)
>  	}
>  
>  	/* DSI VCs initialization */
> -	for (i = 0; i < ARRAY_SIZE(dsi->vc); i++) {
> +	for (i = 0; i < ARRAY_SIZE(dsi->vc); i++)
>  		dsi->vc[i].source = DSI_VC_SOURCE_L4;
> -		dsi->vc[i].dest = NULL;
> -	}
>  
>  	r = dsi_get_clocks(dsi);
>  	if (r)

On 30/11/2020 12:00, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Tue, Nov 24, 2020 at 02:45:20PM +0200, Tomi Valkeinen wrote:
>> The VC handling has gotten quite tangled up. As the first step to clean
>> it up, lets define that we only support a single DSI peripheral (which
>> was really already the case), and we always use VC0 (define VC_DEFAULT
>> 0) register block to send data to the peripheral.
>>
>> We can thus have a single mipi_dsi_device pointer and remove the for
> 
> s/the for/the need for/ ?

Hmm, no, that's not what I was trying to say. Maybe it's clearer with a dash: "remove the for-loops
which..."

> 
>> loops which made passes over all the four VCs (just the first one was
>> ever used).
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>