Re: [PATCH v3 25/56] drm/omap: dsi: move TE GPIO handling into core

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Tomi and Sebastian,

Thank you for the patch.

On Thu, Nov 05, 2020 at 02:03:02PM +0200, Tomi Valkeinen wrote:
> From: Sebastian Reichel <sebastian.reichel@collabora.com>
> 
> In preparation for removing custom DSS calls from the DSI
> panel driver, this moves support for external tearing event
> GPIOs into the DSI host driver. This way tearing events are
> always handled in the core resulting in simplification of
> the panel drivers.
> 
> The TE GPIO acquisition follows works in the same way as the
> exynos DSI implementation.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
>  .../gpu/drm/omapdrm/displays/panel-dsi-cm.c   | 101 +------------
>  drivers/gpu/drm/omapdrm/dss/dsi.c             | 138 ++++++++++++++++--
>  2 files changed, 133 insertions(+), 106 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c b/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
> index 8890ee2ba830..43f63b5a120b 100644
> --- a/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
> +++ b/drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c
> @@ -54,7 +54,6 @@ struct panel_drv_data {
>  
>  	/* panel HW configuration from DT or platform data */
>  	struct gpio_desc *reset_gpio;
> -	struct gpio_desc *ext_te_gpio;
>  
>  	struct regulator_bulk_data supplies[DCS_REGULATOR_SUPPLY_NUM];
>  
> @@ -68,10 +67,6 @@ struct panel_drv_data {
>  
>  	bool te_enabled;
>  
> -	atomic_t do_update;
> -
> -	struct delayed_work te_timeout_work;
> -
>  	bool intro_printed;
>  
>  	struct workqueue_struct *workqueue;
> @@ -83,8 +78,6 @@ struct panel_drv_data {
>  
>  #define to_panel_data(p) container_of(p, struct panel_drv_data, dssdev)
>  
> -static irqreturn_t dsicm_te_isr(int irq, void *data);
> -static void dsicm_te_timeout_work_callback(struct work_struct *work);
>  static int _dsicm_enable_te(struct panel_drv_data *ddata, bool enable);
>  
>  static int dsicm_panel_reset(struct panel_drv_data *ddata);
> @@ -240,9 +233,6 @@ static int dsicm_enter_ulps(struct panel_drv_data *ddata)
>  	if (r)
>  		goto err;
>  
> -	if (ddata->ext_te_gpio)
> -		disable_irq(gpiod_to_irq(ddata->ext_te_gpio));
> -
>  	src->ops->dsi.disable(src, false, true);
>  
>  	ddata->ulps_enabled = true;
> @@ -271,15 +261,12 @@ static int dsicm_exit_ulps(struct panel_drv_data *ddata)
>  	src->ops->enable(src);
>  	ddata->dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>  
> -	r = _dsicm_enable_te(ddata, true);
> +	r = _dsicm_enable_te(ddata, ddata->te_enabled);
>  	if (r) {
>  		dev_err(&ddata->dsi->dev, "failed to re-enable TE");
>  		goto err2;
>  	}
>  
> -	if (ddata->ext_te_gpio)
> -		enable_irq(gpiod_to_irq(ddata->ext_te_gpio));
> -
>  	dsicm_queue_ulps_work(ddata);
>  
>  	ddata->ulps_enabled = false;
> @@ -290,11 +277,8 @@ static int dsicm_exit_ulps(struct panel_drv_data *ddata)
>  	dev_err(&ddata->dsi->dev, "failed to exit ULPS");
>  
>  	r = dsicm_panel_reset(ddata);
> -	if (!r) {
> -		if (ddata->ext_te_gpio)
> -			enable_irq(gpiod_to_irq(ddata->ext_te_gpio));
> +	if (!r)
>  		ddata->ulps_enabled = false;
> -	}
>  
>  	dsicm_queue_ulps_work(ddata);
>  
> @@ -745,43 +729,6 @@ static void dsicm_framedone_cb(int err, void *data)
>  	src->ops->dsi.bus_unlock(src);
>  }
>  
> -static irqreturn_t dsicm_te_isr(int irq, void *data)
> -{
> -	struct panel_drv_data *ddata = data;
> -	struct omap_dss_device *src = ddata->src;
> -	int old;
> -	int r;
> -
> -	old = atomic_cmpxchg(&ddata->do_update, 1, 0);
> -
> -	if (old) {
> -		cancel_delayed_work(&ddata->te_timeout_work);
> -
> -		r = src->ops->dsi.update(src, ddata->dsi->channel, dsicm_framedone_cb,
> -				ddata);
> -		if (r)
> -			goto err;
> -	}
> -
> -	return IRQ_HANDLED;
> -err:
> -	dev_err(&ddata->dsi->dev, "start update failed\n");
> -	src->ops->dsi.bus_unlock(src);
> -	return IRQ_HANDLED;
> -}
> -
> -static void dsicm_te_timeout_work_callback(struct work_struct *work)
> -{
> -	struct panel_drv_data *ddata = container_of(work, struct panel_drv_data,
> -					te_timeout_work.work);
> -	struct omap_dss_device *src = ddata->src;
> -
> -	dev_err(&ddata->dsi->dev, "TE not received for 250ms!\n");
> -
> -	atomic_set(&ddata->do_update, 0);
> -	src->ops->dsi.bus_unlock(src);
> -}
> -
>  static int dsicm_update(struct omap_dss_device *dssdev,
>  				    u16 x, u16 y, u16 w, u16 h)
>  {
> @@ -809,16 +756,10 @@ static int dsicm_update(struct omap_dss_device *dssdev,
>  	if (r)
>  		goto err;
>  
> -	if (ddata->te_enabled && ddata->ext_te_gpio) {
> -		schedule_delayed_work(&ddata->te_timeout_work,
> -				msecs_to_jiffies(250));
> -		atomic_set(&ddata->do_update, 1);
> -	} else {
> -		r = src->ops->dsi.update(src, ddata->dsi->channel, dsicm_framedone_cb,
> -				ddata);
> -		if (r)
> -			goto err;
> -	}
> +	r = src->ops->dsi.update(src, ddata->dsi->channel, dsicm_framedone_cb,
> +			ddata);
> +	if (r)
> +		goto err;
>  
>  	/* note: no bus_unlock here. unlock is src framedone_cb */
>  	mutex_unlock(&ddata->lock);
> @@ -840,8 +781,7 @@ static int _dsicm_enable_te(struct panel_drv_data *ddata, bool enable)
>  	else
>  		r = mipi_dsi_dcs_set_tear_off(dsi);
>  
> -	if (!ddata->ext_te_gpio)
> -		src->ops->dsi.enable_te(src, enable);
> +	src->ops->dsi.enable_te(src, enable);
>  
>  	/* possible panel bug */
>  	msleep(100);
> @@ -934,14 +874,6 @@ static int dsicm_probe_of(struct mipi_dsi_device *dsi)
>  		return err;
>  	}
>  
> -	ddata->ext_te_gpio = devm_gpiod_get_optional(&dsi->dev, "te",
> -						     GPIOD_IN);
> -	if (IS_ERR(ddata->ext_te_gpio)) {
> -		err = PTR_ERR(ddata->ext_te_gpio);
> -		dev_err(&dsi->dev, "TE gpio request failed: %d", err);
> -		return err;
> -	}
> -
>  	err = of_get_display_timing(node, "panel-timing", &timing);
>  	if (!err) {
>  		videomode_from_timing(&timing, &ddata->vm);
> @@ -1024,25 +956,6 @@ static int dsicm_probe(struct mipi_dsi_device *dsi)
>  
>  	mutex_init(&ddata->lock);
>  
> -	atomic_set(&ddata->do_update, 0);
> -
> -	if (ddata->ext_te_gpio) {
> -		r = devm_request_irq(dev, gpiod_to_irq(ddata->ext_te_gpio),
> -				dsicm_te_isr,
> -				IRQF_TRIGGER_RISING,
> -				"taal vsync", ddata);
> -
> -		if (r) {
> -			dev_err(dev, "IRQ request failed\n");
> -			goto err_reg;
> -		}
> -
> -		INIT_DEFERRABLE_WORK(&ddata->te_timeout_work,
> -					dsicm_te_timeout_work_callback);
> -
> -		dev_dbg(dev, "Using GPIO TE\n");
> -	}
> -
>  	ddata->workqueue = create_singlethread_workqueue("dsicm_wq");
>  	if (!ddata->workqueue) {
>  		r = -ENOMEM;
> diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
> index 003d26cead5a..921e7a1e1014 100644
> --- a/drivers/gpu/drm/omapdrm/dss/dsi.c
> +++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
> @@ -14,7 +14,9 @@
>  #include <linux/device.h>
>  #include <linux/err.h>
>  #include <linux/interrupt.h>
> +#include <linux/irq.h>
>  #include <linux/delay.h>
> +#include <linux/gpio/consumer.h>

You could sort the headers while at it :-)

>  #include <linux/mutex.h>
>  #include <linux/module.h>
>  #include <linux/semaphore.h>
> @@ -368,6 +370,11 @@ struct dsi_data {
>  	unsigned int update_bytes;
>  #endif
>  
> +	/* external TE GPIO */
> +	struct gpio_desc *te_gpio;
> +	struct delayed_work te_timeout_work;
> +	atomic_t do_ext_te_update;
> +
>  	bool te_enabled;
>  	bool ulps_enabled;
>  
> @@ -3827,19 +3834,12 @@ static void dsi_framedone_irq_callback(void *data)
>  	dsi_handle_framedone(dsi, 0);
>  }
>  
> -static int dsi_update(struct omap_dss_device *dssdev, int channel,
> -		void (*callback)(int, void *), void *data)
> +static int _dsi_update(struct dsi_data *dsi)
>  {
> -	struct dsi_data *dsi = to_dsi_data(dssdev);
>  	u16 dw, dh;
>  
>  	dsi_perf_mark_setup(dsi);
>  
> -	dsi->update_channel = channel;
> -
> -	dsi->framedone_callback = callback;
> -	dsi->framedone_data = data;
> -
>  	dw = dsi->vm.hactive;
>  	dh = dsi->vm.vactive;
>  
> @@ -3852,6 +3852,26 @@ static int dsi_update(struct omap_dss_device *dssdev, int channel,
>  	return 0;
>  }
>  
> +static int dsi_update(struct omap_dss_device *dssdev, int channel,
> +		void (*callback)(int, void *), void *data)
> +{
> +	struct dsi_data *dsi = to_dsi_data(dssdev);
> +
> +	dsi->update_channel = channel;
> +	dsi->framedone_callback = callback;
> +	dsi->framedone_data = data;
> +
> +	if (dsi->te_enabled && dsi->te_gpio) {
> +		schedule_delayed_work(&dsi->te_timeout_work,
> +				      msecs_to_jiffies(250));
> +		atomic_set(&dsi->do_ext_te_update, 1);
> +	} else {
> +		_dsi_update(dsi);
> +	}
> +
> +	return 0;
> +}
> +
>  /* Display funcs */
>  
>  static int dsi_configure_dispc_clocks(struct dsi_data *dsi)
> @@ -4095,6 +4115,14 @@ static int dsi_enable_te(struct omap_dss_device *dssdev, bool enable)
>  	struct dsi_data *dsi = to_dsi_data(dssdev);
>  
>  	dsi->te_enabled = enable;
> +
> +	if (dsi->te_gpio) {
> +		if (enable)
> +			enable_irq(gpiod_to_irq(dsi->te_gpio));
> +		else
> +			disable_irq(gpiod_to_irq(dsi->te_gpio));
> +	}
> +
>  	return 0;
>  }
>  
> @@ -4772,11 +4800,89 @@ static const struct omap_dss_device_ops dsi_ops = {
>  	},
>  };
>  
> +static irqreturn_t omap_dsi_te_irq_handler(int irq, void *dev_id)
> +{
> +	struct dsi_data *dsi = (struct dsi_data *)dev_id;
> +	int old;
> +
> +	old = atomic_cmpxchg(&dsi->do_ext_te_update, 1, 0);
> +	if (old) {
> +		cancel_delayed_work(&dsi->te_timeout_work);
> +		_dsi_update(dsi);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void omap_dsi_te_timeout_work_callback(struct work_struct *work)
> +{
> +	struct dsi_data *dsi = container_of(work, struct dsi_data,
> +					te_timeout_work.work);

Strange indentation.

> +	int old;
> +
> +	old = atomic_cmpxchg(&dsi->do_ext_te_update, 1, 0);
> +	if (old) {
> +		dev_err(dsi->dev, "TE not received for 250ms!\n");
> +		_dsi_update(dsi);
> +	}
> +}
> +
> +static int omap_dsi_register_te_irq(struct dsi_data *dsi,
> +				    struct mipi_dsi_device *client)
> +{
> +	int err;
> +	int te_irq;
> +
> +	dsi->te_gpio = gpiod_get_from_of_node(client->dev.of_node,

Could we call gpiod_get(&client->dev, "te", ...) instead ?

> +					      "te-gpios", 0, GPIOD_IN,
> +					      "dsi-tearing-effect");
> +	if (IS_ERR(dsi->te_gpio)) {
> +		err = PTR_ERR(dsi->te_gpio);
> +
> +		if (err == -ENOENT) {
> +			dsi->te_gpio = NULL;
> +			return 0;
> +		}
> +
> +		dev_err(dsi->dev, "Could not get TE gpio: %d\n", err);
> +		return err;
> +	}
> +
> +	te_irq = gpiod_to_irq(dsi->te_gpio);

Could this fail ?

> +	irq_set_status_flags(te_irq, IRQ_NOAUTOEN);
> +
> +	err = request_threaded_irq(te_irq, omap_dsi_te_irq_handler, NULL,
> +				   IRQF_TRIGGER_RISING, "TE", dsi);

What's the reason to request a threaded IRQ instead of a regular IRQ if
the threaded handler is NULL ?

> +	if (err) {
> +		dev_err(dsi->dev, "request irq failed with %d\n", err);
> +		gpiod_put(dsi->te_gpio);
> +		return err;
> +	}
> +
> +	INIT_DEFERRABLE_WORK(&dsi->te_timeout_work,
> +			     omap_dsi_te_timeout_work_callback);
> +
> +	dev_dbg(dsi->dev, "Using GPIO TE\n");
> +
> +	return 0;
> +}
> +
> +static void omap_dsi_unregister_te_irq(struct dsi_data *dsi)
> +{
> +	if (dsi->te_gpio) {
> +		free_irq(gpiod_to_irq(dsi->te_gpio), dsi);

You could store the IRQ number in dsi_data to avoid recomputing it.

> +		cancel_delayed_work(&dsi->te_timeout_work);
> +		gpiod_put(dsi->te_gpio);
> +		dsi->te_gpio = NULL;
> +	}
> +}
> +
>  static int omap_dsi_host_attach(struct mipi_dsi_host *host,
>  				struct mipi_dsi_device *client)
>  {
>  	struct dsi_data *dsi = host_to_omap(host);
>  	unsigned int channel = client->channel;
> +	int r;
>  
>  	if (channel > 3)
>  		return -EINVAL;
> @@ -4791,13 +4897,20 @@ static int omap_dsi_host_attach(struct mipi_dsi_host *host,
>  		return -EINVAL;
>  	}
>  
> -	dsi->vc[channel].dest = client;
> +	atomic_set(&dsi->do_ext_te_update, 0);
>  
> -	dsi->pix_fmt = client->format;
> -	if (client->mode_flags & MIPI_DSI_MODE_VIDEO)
> +	if (client->mode_flags & MIPI_DSI_MODE_VIDEO) {
>  		dsi->mode = OMAP_DSS_DSI_VIDEO_MODE;
> -	else
> +	} else {
> +		r = omap_dsi_register_te_irq(dsi, client);
> +		if (r)
> +			return r;
> +
>  		dsi->mode = OMAP_DSS_DSI_CMD_MODE;
> +	}
> +
> +	dsi->vc[channel].dest = client;
> +	dsi->pix_fmt = client->format;
>  
>  	return 0;
>  }
> @@ -4814,6 +4927,7 @@ static int omap_dsi_host_detach(struct mipi_dsi_host *host,
>  	if (dsi->vc[channel].dest != client)
>  		return -EINVAL;
>  
> +	omap_dsi_unregister_te_irq(dsi);
>  	dsi->vc[channel].dest = NULL;
>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart