1. Patchew
  2. linux
  3. View series

[PATCH v1] drm/bridge: tc358768: Fix DSI command tx

Francesco Dolcini posted 1 patch 1 year, 4 months ago 
drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
[PATCH v1] drm/bridge: tc358768: Fix DSI command tx
Posted by Francesco Dolcini 1 year, 4 months ago 
From: Francesco Dolcini <francesco.dolcini@toradex.com>

Wait for the command transmission to be completed in the DSI transfer
function polling for the dc_start bit to go back to idle state after the
transmission is started.

This is documented in the datasheet and failures to do so lead to
commands corruption.

Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Cc: stable@vger.kernel.org
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 0e8813278a2f..bb1750a3dab0 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -125,6 +125,9 @@
 #define TC358768_DSI_CONFW_MODE_CLR	(6 << 29)
 #define TC358768_DSI_CONFW_ADDR_DSI_CONTROL	(0x3 << 24)
 
+/* TC358768_DSICMD_TX (0x0600) register */
+#define TC358768_DSI_CMDTX_DC_START	BIT(0)
+
 static const char * const tc358768_supplies[] = {
 	"vddc", "vddmipi", "vddio"
 };
@@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
 		tc358768_write(priv, reg, tmp);
 }
 
+static void tc358768_dsicmd_tx(struct tc358768_priv *priv)
+{
+	u32 val;
+
+	/* start transfer */
+	tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START);
+	if (priv->error)
+		return;
+
+	/* wait transfer completion */
+	priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val,
+					       (val & TC358768_DSI_CMDTX_DC_START) == 0,
+					       100, 100000);
+}
+
 static int tc358768_sw_reset(struct tc358768_priv *priv)
 {
 	/* Assert Reset */
@@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
 		}
 	}
 
-	/* start transfer */
-	tc358768_write(priv, TC358768_DSICMD_TX, 1);
+	tc358768_dsicmd_tx(priv);
 
 	ret = tc358768_clear_error(priv);
 	if (ret)
-- 
2.39.5
Re: [PATCH v1] drm/bridge: tc358768: Fix DSI command tx
Posted by Neil Armstrong 1 year, 2 months ago 
Hi,

On Thu, 26 Sep 2024 16:12:46 +0200, Francesco Dolcini wrote:
> Wait for the command transmission to be completed in the DSI transfer
> function polling for the dc_start bit to go back to idle state after the
> transmission is started.
> 
> This is documented in the datasheet and failures to do so lead to
> commands corruption.
> 
> [...]

Thanks, Applied to https://gitlab.freedesktop.org/drm/misc/kernel.git (drm-misc-fixes)

[1/1] drm/bridge: tc358768: Fix DSI command tx
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/32c4514455b2b8fde506f8c0962f15c7e4c26f1d

-- 
Neil
Re: [PATCH v1] drm/bridge: tc358768: Fix DSI command tx
Posted by Neil Armstrong 1 year, 3 months ago 
On 26/09/2024 16:12, Francesco Dolcini wrote:
> From: Francesco Dolcini <francesco.dolcini@toradex.com>
> 
> Wait for the command transmission to be completed in the DSI transfer
> function polling for the dc_start bit to go back to idle state after the
> transmission is started.
> 
> This is documented in the datasheet and failures to do so lead to
> commands corruption.
> 
> Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
> ---
>   drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
>   1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> index 0e8813278a2f..bb1750a3dab0 100644
> --- a/drivers/gpu/drm/bridge/tc358768.c
> +++ b/drivers/gpu/drm/bridge/tc358768.c
> @@ -125,6 +125,9 @@
>   #define TC358768_DSI_CONFW_MODE_CLR	(6 << 29)
>   #define TC358768_DSI_CONFW_ADDR_DSI_CONTROL	(0x3 << 24)
>   
> +/* TC358768_DSICMD_TX (0x0600) register */
> +#define TC358768_DSI_CMDTX_DC_START	BIT(0)
> +
>   static const char * const tc358768_supplies[] = {
>   	"vddc", "vddmipi", "vddio"
>   };
> @@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
>   		tc358768_write(priv, reg, tmp);
>   }
>   
> +static void tc358768_dsicmd_tx(struct tc358768_priv *priv)
> +{
> +	u32 val;
> +
> +	/* start transfer */
> +	tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START);
> +	if (priv->error)
> +		return;
> +
> +	/* wait transfer completion */
> +	priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val,
> +					       (val & TC358768_DSI_CMDTX_DC_START) == 0,
> +					       100, 100000);
> +}
> +
>   static int tc358768_sw_reset(struct tc358768_priv *priv)
>   {
>   	/* Assert Reset */
> @@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
>   		}
>   	}
>   
> -	/* start transfer */
> -	tc358768_write(priv, TC358768_DSICMD_TX, 1);
> +	tc358768_dsicmd_tx(priv);
>   
>   	ret = tc358768_clear_error(priv);
>   	if (ret)

Look good, I'll leave it here a few days if someone has comments

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Re: [PATCH v1] drm/bridge: tc358768: Fix DSI command tx
Posted by Francesco Dolcini 1 year, 2 months ago 
Hello Neil,

On Wed, Oct 23, 2024 at 10:03:20AM +0200, Neil Armstrong wrote:
> On 26/09/2024 16:12, Francesco Dolcini wrote:
> > From: Francesco Dolcini <francesco.dolcini@toradex.com>
> > 
> > Wait for the command transmission to be completed in the DSI transfer
> > function polling for the dc_start bit to go back to idle state after the
> > transmission is started.
> > 
> > This is documented in the datasheet and failures to do so lead to
> > commands corruption.
> > 
> > Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
> > ---
> >   drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
> >   1 file changed, 19 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> > index 0e8813278a2f..bb1750a3dab0 100644
> > --- a/drivers/gpu/drm/bridge/tc358768.c
> > +++ b/drivers/gpu/drm/bridge/tc358768.c
> > @@ -125,6 +125,9 @@
> >   #define TC358768_DSI_CONFW_MODE_CLR	(6 << 29)
> >   #define TC358768_DSI_CONFW_ADDR_DSI_CONTROL	(0x3 << 24)
> > +/* TC358768_DSICMD_TX (0x0600) register */
> > +#define TC358768_DSI_CMDTX_DC_START	BIT(0)
> > +
> >   static const char * const tc358768_supplies[] = {
> >   	"vddc", "vddmipi", "vddio"
> >   };
> > @@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
> >   		tc358768_write(priv, reg, tmp);
> >   }
> > +static void tc358768_dsicmd_tx(struct tc358768_priv *priv)
> > +{
> > +	u32 val;
> > +
> > +	/* start transfer */
> > +	tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START);
> > +	if (priv->error)
> > +		return;
> > +
> > +	/* wait transfer completion */
> > +	priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val,
> > +					       (val & TC358768_DSI_CMDTX_DC_START) == 0,
> > +					       100, 100000);
> > +}
> > +
> >   static int tc358768_sw_reset(struct tc358768_priv *priv)
> >   {
> >   	/* Assert Reset */
> > @@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
> >   		}
> >   	}
> > -	/* start transfer */
> > -	tc358768_write(priv, TC358768_DSICMD_TX, 1);
> > +	tc358768_dsicmd_tx(priv);
> >   	ret = tc358768_clear_error(priv);
> >   	if (ret)
> 
> Look good, I'll leave it here a few days if someone has comments

Just a gently reminder, thanks

> Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Francesco
Re: [PATCH v1] drm/bridge: tc358768: Fix DSI command tx
Posted by Francesco Dolcini 1 year, 3 months ago 
Hello,

On Thu, Sep 26, 2024 at 04:12:46PM +0200, Francesco Dolcini wrote:
> From: Francesco Dolcini <francesco.dolcini@toradex.com>
> 
> Wait for the command transmission to be completed in the DSI transfer
> function polling for the dc_start bit to go back to idle state after the
> transmission is started.
> 
> This is documented in the datasheet and failures to do so lead to
> commands corruption.
> 
> Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>

Just a gently ping on this,

Francesco

Patchew 2.1-devel-b67e4c2

© 2016 - 2026 Red Hat, Inc.