Re: [PATCH 1/4] drm/dsi: Make mipi_dsi_dcs_write() return ssize_t

[Andrzej Hajda <a.hajda@samsung.com>]

On 07/22/2014 11:50 AM, YoungJun Cho wrote:
> Hi,
>
> On 07/22/2014 04:28 PM, Andrzej Hajda wrote:
>> Hi Thierry,
>>
>> Thanks for the patch.
>>
>> On 07/22/2014 09:12 AM, Thierry Reding wrote:
>>> From: Thierry Reding <treding@nvidia.com>
>>>
>>> This function returns the value of the struct mipi_dsi_host_ops'
>>> .transfer() so make sure the return types are consistent.
>>>
>>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>> Acked-by: Andrzej Hajda <a.hajda@samsung.com>
>> --
>> Regards
>> Andrzej
>>> ---
>>>   drivers/gpu/drm/drm_mipi_dsi.c        | 4 ++--
>>>   drivers/gpu/drm/panel/panel-s6e8aa0.c | 4 ++--
>>>   include/drm/drm_mipi_dsi.h            | 4 ++--
>>>   3 files changed, 6 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
>>> index e633df2f68d8..6d2fd2077dae 100644
>>> --- a/drivers/gpu/drm/drm_mipi_dsi.c
>>> +++ b/drivers/gpu/drm/drm_mipi_dsi.c
>>> @@ -205,8 +205,8 @@ EXPORT_SYMBOL(mipi_dsi_detach);
>>>    * @data: pointer to the command followed by parameters
>>>    * @len: length of @data
>>>    */
>>> -int mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
>>> -		       const void *data, size_t len)
>>> +ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
>>> +			   const void *data, size_t len)
>>>   {
>>>   	const struct mipi_dsi_host_ops *ops = dsi->host->ops;
>>>   	struct mipi_dsi_msg msg = {
>>> diff --git a/drivers/gpu/drm/panel/panel-s6e8aa0.c b/drivers/gpu/drm/panel/panel-s6e8aa0.c
>>> index 06e57a26db7a..beb43492b649 100644
>>> --- a/drivers/gpu/drm/panel/panel-s6e8aa0.c
>>> +++ b/drivers/gpu/drm/panel/panel-s6e8aa0.c
>>> @@ -133,14 +133,14 @@ static int s6e8aa0_clear_error(struct s6e8aa0 *ctx)
>>>   static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const void *data, size_t len)
>>>   {
>>>   	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
>>> -	int ret;
>>> +	ssize_t ret;
>>>
>>>   	if (ctx->error < 0)
>>>   		return;
>>>
>>>   	ret = mipi_dsi_dcs_write(dsi, dsi->channel, data, len);
>>>   	if (ret < 0) {
>>> -		dev_err(ctx->dev, "error %d writing dcs seq: %*ph\n", ret, len,
>>> +		dev_err(ctx->dev, "error %zd writing dcs seq: %*ph\n", ret, len,
>>>   			data);
>>>   		ctx->error = ret;
> One more thing!
> This 'ctx->error' type is 'int'. So it should be changed from int to 
> ssize_t in struct s6e8aa0.
I do not think so. ctx->error contains always error code, and this is
guarded here
by 'if (ret < 0)'  clause.

Regards
Andrzej
>
> Thank you.
> Best regards YJ
>
>>>   	}
>>> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
>>> index efa1b552adc5..4b0112781910 100644
>>> --- a/include/drm/drm_mipi_dsi.h
>>> +++ b/include/drm/drm_mipi_dsi.h
>>> @@ -127,8 +127,8 @@ struct mipi_dsi_device {
>>>
>>>   int mipi_dsi_attach(struct mipi_dsi_device *dsi);
>>>   int mipi_dsi_detach(struct mipi_dsi_device *dsi);
>>> -int mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
>>> -		       const void *data, size_t len);
>>> +ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, unsigned int channel,
>>> +			   const void *data, size_t len);
>>>   ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, unsigned int channel,
>>>   			  u8 cmd, void *data, size_t len);
>>>
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>