Re: [PATCH 03/24] drm/omap: add HPD support to connector-dvi

[Tomi Valkeinen <tomi.valkeinen@ti.com>]

On 27/02/18 14:58, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Monday, 12 February 2018 11:44:33 EET Tomi Valkeinen wrote:
>> Add HPD support to the DVI connector driver. The code is almost
>> identical to the HPD code in the HDMI connector driver.
> 
> Would it make sense to share a single implementation then ? Or is that an 
> exercise left for the reader (that is, me) ? :-)

It would, but I suspect all these will go away soon with the
drm_bridge/panel work, so I didn't want to start doing a bigger refactoring.

>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
>> ---
>>  drivers/gpu/drm/omapdrm/displays/connector-dvi.c | 114 ++++++++++++++++++++
>>  1 file changed, 114 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/omapdrm/displays/connector-dvi.c
>> b/drivers/gpu/drm/omapdrm/displays/connector-dvi.c index
>> 391d80364346..f9f8700223c3 100644
>> --- a/drivers/gpu/drm/omapdrm/displays/connector-dvi.c
>> +++ b/drivers/gpu/drm/omapdrm/displays/connector-dvi.c
>> @@ -13,6 +13,7 @@
>>  #include <linux/module.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/slab.h>
>> +#include <linux/gpio/consumer.h>
> 
> Could you please keep headers alphabetically sorted ?

Sure.

>>  #include <drm/drm_edid.h>
>>
>> @@ -44,6 +45,13 @@ struct panel_drv_data {
>>  	struct videomode vm;
>>
>>  	struct i2c_adapter *i2c_adapter;
>> +
>> +	struct gpio_desc *hpd_gpio;
>> +
>> +	void (*hpd_cb)(void *cb_data, enum drm_connector_status status);
>> +	void *hpd_cb_data;
>> +	bool hpd_enabled;
>> +	struct mutex hpd_lock;
> 
> Locks should have a comment that describes which fields they protect.

Added.
>>  };
>>
>>  #define to_panel_data(x) container_of(x, struct panel_drv_data, dssdev)
>> @@ -189,6 +197,9 @@ static int dvic_read_edid(struct omap_dss_device
>> *dssdev, struct panel_drv_data *ddata = to_panel_data(dssdev);
>>  	int r, l, bytes_read;
>>
>> +	if (ddata->hpd_gpio && !gpiod_get_value_cansleep(ddata->hpd_gpio))
>> +		return -ENODEV;
>> +
>>  	if (!ddata->i2c_adapter)
>>  		return -ENODEV;
>>
>> @@ -220,6 +231,9 @@ static bool dvic_detect(struct omap_dss_device *dssdev)
>>  	unsigned char out;
>>  	int r;
>>
>> +	if (ddata->hpd_gpio)
>> +		return gpiod_get_value_cansleep(ddata->hpd_gpio);
>> +
>>  	if (!ddata->i2c_adapter)
>>  		return true;
>>
>> @@ -228,6 +242,60 @@ static bool dvic_detect(struct omap_dss_device *dssdev)
>> return r == 0;
>>  }
>>
>> +static int dvic_register_hpd_cb(struct omap_dss_device *dssdev,
>> +				 void (*cb)(void *cb_data,
>> +					    enum drm_connector_status status),
>> +				 void *cb_data)
>> +{
>> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
>> +
>> +	if (!ddata->hpd_gpio)
>> +		return -ENOTSUPP;
>> +
>> +	mutex_lock(&ddata->hpd_lock);
>> +	ddata->hpd_cb = cb;
>> +	ddata->hpd_cb_data = cb_data;
>> +	mutex_unlock(&ddata->hpd_lock);
>> +	return 0;
>> +}
>> +
>> +static void dvic_unregister_hpd_cb(struct omap_dss_device *dssdev)
>> +{
>> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
>> +
>> +	if (!ddata->hpd_gpio)
>> +		return;
>> +
>> +	mutex_lock(&ddata->hpd_lock);
>> +	ddata->hpd_cb = NULL;
>> +	ddata->hpd_cb_data = NULL;
>> +	mutex_unlock(&ddata->hpd_lock);
>> +}
>> +
>> +static void dvic_enable_hpd(struct omap_dss_device *dssdev)
>> +{
>> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
>> +
>> +	if (!ddata->hpd_gpio)
>> +		return;
>> +
>> +	mutex_lock(&ddata->hpd_lock);
>> +	ddata->hpd_enabled = true;
>> +	mutex_unlock(&ddata->hpd_lock);
>> +}
>> +
>> +static void dvic_disable_hpd(struct omap_dss_device *dssdev)
>> +{
>> +	struct panel_drv_data *ddata = to_panel_data(dssdev);
>> +
>> +	if (!ddata->hpd_gpio)
>> +		return;
>> +
>> +	mutex_lock(&ddata->hpd_lock);
>> +	ddata->hpd_enabled = false;
>> +	mutex_unlock(&ddata->hpd_lock);
>> +}
>> +
>>  static struct omap_dss_driver dvic_driver = {
>>  	.connect	= dvic_connect,
>>  	.disconnect	= dvic_disconnect,
>> @@ -241,14 +309,60 @@ static struct omap_dss_driver dvic_driver = {
>>
>>  	.read_edid	= dvic_read_edid,
>>  	.detect		= dvic_detect,
>> +
>> +	.register_hpd_cb	= dvic_register_hpd_cb,
>> +	.unregister_hpd_cb	= dvic_unregister_hpd_cb,
>> +	.enable_hpd		= dvic_enable_hpd,
>> +	.disable_hpd		= dvic_disable_hpd,
>>  };
>>
>> +static irqreturn_t dvic_hpd_isr(int irq, void *data)
>> +{
>> +	struct panel_drv_data *ddata = data;
>> +
>> +	mutex_lock(&ddata->hpd_lock);
>> +	if (ddata->hpd_enabled && ddata->hpd_cb) {
>> +		enum drm_connector_status status;
>> +
>> +		if (dvic_detect(&ddata->dssdev))
>> +			status = connector_status_connected;
>> +		else
>> +			status = connector_status_disconnected;
>> +
>> +		ddata->hpd_cb(ddata->hpd_cb_data, status);
>> +	}
>> +	mutex_unlock(&ddata->hpd_lock);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>>  static int dvic_probe_of(struct platform_device *pdev)
>>  {
>>  	struct panel_drv_data *ddata = platform_get_drvdata(pdev);
>>  	struct device_node *node = pdev->dev.of_node;
>>  	struct device_node *adapter_node;
>>  	struct i2c_adapter *adapter;
>> +	struct gpio_desc *gpio;
>> +	int r;
>> +
>> +	gpio = devm_gpiod_get_optional(&pdev->dev, "hpd", GPIOD_IN);
>> +	if (IS_ERR(gpio)) {
>> +		dev_err(&pdev->dev, "failed to parse HPD gpio\n");
>> +		return PTR_ERR(gpio);
>> +	}
>> +
>> +	ddata->hpd_gpio = gpio;
>> +
>> +	mutex_init(&ddata->hpd_lock);
> 
> Shouldn't you also have a mutex_destroy ?

Yep. Interestingly, we don't destroy any of the mutexes in omapdss/drm.
Luckily mutex_destroy doesn't seem to do much (just for debug purposes),
but still, we need to add those at some point.

 Tomi

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