Re: [PATCH v4 10/15] drm/bridge: tc358767: Add support for address-only I2C transfers

2019-06-06 Thread Andrzej Hajda
On 07.06.2019 06:45, Andrey Smirnov wrote:
> Transfer size of zero means a request to do an address-only
> transfer. Since the HW support this, we probably shouldn't be just
> ignoring such requests. While at it allow DP_AUX_I2C_MOT flag to pass
> through, since it is supported by the HW as well.
>
> Signed-off-by: Andrey Smirnov 
Reviewed-by: Andrzej Hajda 

 --
Regards
Andrzej
> Cc: Andrzej Hajda 
> Cc: Laurent Pinchart 
> Cc: Tomi Valkeinen 
> Cc: Andrey Gusakov 
> Cc: Philipp Zabel 
> Cc: Cory Tusar 
> Cc: Chris Healy 
> Cc: Lucas Stach 
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-ker...@vger.kernel.org
> ---
>  drivers/gpu/drm/bridge/tc358767.c | 30 +++---
>  1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c 
> b/drivers/gpu/drm/bridge/tc358767.c
> index 7d0fbb12195b..4bb9b15e1324 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -145,6 +145,8 @@
>  
>  /* AUX channel */
>  #define DP0_AUXCFG0  0x0660
> +#define DP0_AUXCFG0_BSIZEGENMASK(11, 8)
> +#define DP0_AUXCFG0_ADDR_ONLYBIT(4)
>  #define DP0_AUXCFG1  0x0664
>  #define AUX_RX_FILTER_EN BIT(16)
>  
> @@ -327,6 +329,18 @@ static int tc_aux_read_data(struct tc_data *tc, void 
> *data, size_t size)
>   return size;
>  }
>  
> +static u32 tc_auxcfg0(struct drm_dp_aux_msg *msg, size_t size)
> +{
> + u32 auxcfg0 = msg->request;
> +
> + if (size)
> + auxcfg0 |= FIELD_PREP(DP0_AUXCFG0_BSIZE, size - 1);
> + else
> + auxcfg0 |= DP0_AUXCFG0_ADDR_ONLY;
> +
> + return auxcfg0;
> +}
> +
>  static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
>  struct drm_dp_aux_msg *msg)
>  {
> @@ -336,9 +350,6 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
>   u32 auxstatus;
>   int ret;
>  
> - if (size == 0)
> - return 0;
> -
>   ret = tc_aux_wait_busy(tc, 100);
>   if (ret)
>   return ret;
> @@ -362,8 +373,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
>   if (ret)
>   return ret;
>   /* Start transfer */
> - ret = regmap_write(tc->regmap, DP0_AUXCFG0,
> -((size - 1) << 8) | request);
> + ret = regmap_write(tc->regmap, DP0_AUXCFG0, tc_auxcfg0(msg, size));
>   if (ret)
>   return ret;
>  
> @@ -377,8 +387,14 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
>  
>   if (auxstatus & AUX_TIMEOUT)
>   return -ETIMEDOUT;
> -
> - size = FIELD_GET(AUX_BYTES, auxstatus);
> + /*
> +  * For some reason address-only DP_AUX_I2C_WRITE (MOT), still
> +  * reports 1 byte transferred in its status. To deal we that
> +  * we ignore aux_bytes field if we know that this was an
> +  * address-only transfer
> +  */
> + if (size)
> + size = FIELD_GET(AUX_BYTES, auxstatus);
>   msg->reply = FIELD_GET(AUX_STATUS, auxstatus);
>  
>   switch (request) {


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[PATCH v4 10/15] drm/bridge: tc358767: Add support for address-only I2C transfers

2019-06-06 Thread Andrey Smirnov
Transfer size of zero means a request to do an address-only
transfer. Since the HW support this, we probably shouldn't be just
ignoring such requests. While at it allow DP_AUX_I2C_MOT flag to pass
through, since it is supported by the HW as well.

Signed-off-by: Andrey Smirnov 
Cc: Andrzej Hajda 
Cc: Laurent Pinchart 
Cc: Tomi Valkeinen 
Cc: Andrey Gusakov 
Cc: Philipp Zabel 
Cc: Cory Tusar 
Cc: Chris Healy 
Cc: Lucas Stach 
Cc: dri-devel@lists.freedesktop.org
Cc: linux-ker...@vger.kernel.org
---
 drivers/gpu/drm/bridge/tc358767.c | 30 +++---
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c 
b/drivers/gpu/drm/bridge/tc358767.c
index 7d0fbb12195b..4bb9b15e1324 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -145,6 +145,8 @@
 
 /* AUX channel */
 #define DP0_AUXCFG00x0660
+#define DP0_AUXCFG0_BSIZE  GENMASK(11, 8)
+#define DP0_AUXCFG0_ADDR_ONLY  BIT(4)
 #define DP0_AUXCFG10x0664
 #define AUX_RX_FILTER_EN   BIT(16)
 
@@ -327,6 +329,18 @@ static int tc_aux_read_data(struct tc_data *tc, void 
*data, size_t size)
return size;
 }
 
+static u32 tc_auxcfg0(struct drm_dp_aux_msg *msg, size_t size)
+{
+   u32 auxcfg0 = msg->request;
+
+   if (size)
+   auxcfg0 |= FIELD_PREP(DP0_AUXCFG0_BSIZE, size - 1);
+   else
+   auxcfg0 |= DP0_AUXCFG0_ADDR_ONLY;
+
+   return auxcfg0;
+}
+
 static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
   struct drm_dp_aux_msg *msg)
 {
@@ -336,9 +350,6 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
u32 auxstatus;
int ret;
 
-   if (size == 0)
-   return 0;
-
ret = tc_aux_wait_busy(tc, 100);
if (ret)
return ret;
@@ -362,8 +373,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
if (ret)
return ret;
/* Start transfer */
-   ret = regmap_write(tc->regmap, DP0_AUXCFG0,
-  ((size - 1) << 8) | request);
+   ret = regmap_write(tc->regmap, DP0_AUXCFG0, tc_auxcfg0(msg, size));
if (ret)
return ret;
 
@@ -377,8 +387,14 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
 
if (auxstatus & AUX_TIMEOUT)
return -ETIMEDOUT;
-
-   size = FIELD_GET(AUX_BYTES, auxstatus);
+   /*
+* For some reason address-only DP_AUX_I2C_WRITE (MOT), still
+* reports 1 byte transferred in its status. To deal we that
+* we ignore aux_bytes field if we know that this was an
+* address-only transfer
+*/
+   if (size)
+   size = FIELD_GET(AUX_BYTES, auxstatus);
msg->reply = FIELD_GET(AUX_STATUS, auxstatus);
 
switch (request) {
-- 
2.21.0