On 06/12/2018 22:26, Laurent Pinchart wrote:
> The TFP410 supports configurable pixel clock sampling edge and data
> de-skew adjustments. The configuration can be set through I2C or
> dedicated chip pins.
>
> Report the configuration through the drm_bridge timings. As the
> ti-tftp410 driver doesn't support configuring the chip through I2C, we
> simply use the default configuration in that case. When the chip is
> configured through dedicated pins, we parse the configuration from DT.
>
> Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> ---
> drivers/gpu/drm/bridge/ti-tfp410.c | 77 ++++++++++++++++++++++++++++--
> 1 file changed, 74 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c
> b/drivers/gpu/drm/bridge/ti-tfp410.c
> index d25d23cfe3f5..48ec647a7526 100644
> --- a/drivers/gpu/drm/bridge/ti-tfp410.c
> +++ b/drivers/gpu/drm/bridge/ti-tfp410.c
> @@ -34,6 +34,8 @@ struct tfp410 {
> struct delayed_work hpd_work;
> struct gpio_desc *powerdown;
>
> + struct drm_bridge_timings timings;
> +
> struct device *dev;
> };
>
> @@ -180,6 +182,70 @@ static irqreturn_t tfp410_hpd_irq_thread(int irq, void
> *arg)
> return IRQ_HANDLED;
> }
>
> +static const struct drm_bridge_timings tfp410_default_timings = {
> + .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
> + | DRM_BUS_FLAG_DE_HIGH,
> + .setup_time_ps = 1200,
> + .hold_time_ps = 1300,
> +};
> +
> +static int tfp410_parse_timings(struct tfp410 *dvi, bool i2c)
> +{
> + struct drm_bridge_timings *timings = &dvi->timings;
> + struct device_node *ep;
> + u32 pclk_sample = 0;
> + s32 deskew = 0;
> +
> + /* Start with defaults. */
> + *timings = tfp410_default_timings;
> +
> + if (i2c)
> + /*
> + * In I2C mode timings are configured through the I2C interface.
> + * As the driver doesn't support I2C configuration yet, we just
> + * go with the defaults (BSEL=1, DSEL=1, DKEN=0, EDGE=1).
> + */
> + return 0;
> +
> + /*
> + * In non-I2C mode, timings are configured through the BSEL, DSEL, DKEN
> + * and EDGE pins. They are specified in DT through endpoint properties
> + * and vendor-specific properties.
> + */
> + ep = of_graph_get_endpoint_by_regs(dvi->dev->of_node, 0, 0);
> + if (!ep)
> + return -EINVAL;
> +
> + /* Get the sampling edge from the endpoint. */
> + of_property_read_u32(ep, "pclk-sample", &pclk_sample);
> + of_node_put(ep);
> +
> + timings->input_bus_flags = DRM_BUS_FLAG_DE_HIGH;
> +
> + switch (pclk_sample) {
> + case 0:
> + timings->input_bus_flags |= DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE
> + | DRM_BUS_FLAG_SYNC_SAMPLE_NEGEDGE;
> + break;
> + case 1:
> + timings->input_bus_flags |= DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE
> + | DRM_BUS_FLAG_SYNC_SAMPLE_POSEDGE;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + /* Get the setup and hold time from vendor-specific properties. */
> + of_property_read_u32(dvi->dev->of_node, "ti,deskew", (u32 *)&deskew);
> + if (deskew < -4 || deskew > 3)
> + return -EINVAL;
Is "ti,deskew" property documented somewhere? If it is, I could not find
it. Could it be added to the tfp410 binding document, or somewhere else?
Othewise:
Reviewed-by: Jyri Sarha <jsa...@ti.com>
> +
> + timings->setup_time_ps = min(0, 1200 - 350 * deskew);
> + timings->hold_time_ps = min(0, 1300 + 350 * deskew);
> +
> + return 0;
> +}
> +
> static int tfp410_get_connector_properties(struct tfp410 *dvi)
> {
> struct device_node *connector_node, *ddc_phandle;
> @@ -223,7 +289,7 @@ static int tfp410_get_connector_properties(struct tfp410
> *dvi)
> return ret;
> }
>
> -static int tfp410_init(struct device *dev)
> +static int tfp410_init(struct device *dev, bool i2c)
> {
> struct tfp410 *dvi;
> int ret;
> @@ -240,8 +306,13 @@ static int tfp410_init(struct device *dev)
>
> dvi->bridge.funcs = &tfp410_bridge_funcs;
> dvi->bridge.of_node = dev->of_node;
> + dvi->bridge.timings = &dvi->timings;
> dvi->dev = dev;
>
> + ret = tfp410_parse_timings(dvi, i2c);
> + if (ret)
> + goto fail;
> +
> ret = tfp410_get_connector_properties(dvi);
> if (ret)
> goto fail;
> @@ -294,7 +365,7 @@ static int tfp410_fini(struct device *dev)
>
> static int tfp410_probe(struct platform_device *pdev)
> {
> - return tfp410_init(&pdev->dev);
> + return tfp410_init(&pdev->dev, false);
> }
>
> static int tfp410_remove(struct platform_device *pdev)
> @@ -331,7 +402,7 @@ static int tfp410_i2c_probe(struct i2c_client *client,
> return -ENXIO;
> }
>
> - return tfp410_init(&client->dev);
> + return tfp410_init(&client->dev, true);
> }
>
> static int tfp410_i2c_remove(struct i2c_client *client)
>
--
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