Re: [PATCH v2 4/8] drm: mipi: add mipi_dsi_generic_write_multi_type()

[Jessica Zhang <quic_jesszhan@quicinc.com>]

On 6/30/2024 11:36 AM, Caleb Connolly wrote:
> Some panels like the Samsung AMB655X use long write commands for all
> non-standard messages and do not work when trying to use the appropriate
> command type.
> 
> Support these panels by introducing a new helper to send commands of a
> specific type, overriding the normal rules.
> 
> Signed-off-by: Caleb Connolly <caleb@postmarketos.org>
> ---
>   drivers/gpu/drm/drm_mipi_dsi.c | 40 ++++++++++++++++++++++++++++++++++++++++
>   include/drm/drm_mipi_dsi.h     | 16 ++++++++++++++++
>   2 files changed, 56 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> index a471c46f5ca6..f2c7f3f23a6e 100644
> --- a/drivers/gpu/drm/drm_mipi_dsi.c
> +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> @@ -819,8 +819,48 @@ void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
>   	}
>   }
>   EXPORT_SYMBOL(mipi_dsi_generic_write_multi);
>   
> +/**
> + * mipi_dsi_generic_write_raw_multi() - transmit data using a generic write packet of
> + * a specific type
> + * @ctx: Context for multiple DSI transactions
> + * @type: data type of the packet
> + * @payload: buffer containing the payload
> + * @size: size of payload buffer
> + *
> + * This function will automatically choose the right data type depending on
> + * the payload length.

Hi Caleb,

I'm a bit confused by the wording here. By "automatically", do you mean 
the chosen by the macro calling this function?

Thanks,

Jessica Zhang

> + *
> + * Return: The number of bytes transmitted on success or a negative error code
> + * on failure.
> + */
> +ssize_t mipi_dsi_generic_write_raw_multi(struct mipi_dsi_multi_context *ctx,
> +					  u8 type, const void *payload, size_t size)
> +{
> +	struct mipi_dsi_device *dsi = ctx->dsi;
> +	struct mipi_dsi_msg msg = {
> +		.channel = dsi->channel,
> +		.tx_buf = payload,
> +		.tx_len = size,
> +		.type = type,
> +	};
> +	ssize_t ret;
> +
> +	if (ctx->accum_err)
> +		return 0;
> +
> +	ret = mipi_dsi_device_transfer(dsi, &msg);
> +	if (ret < 0) {
> +		ctx->accum_err = ret;
> +		dev_err(&dsi->dev, "sending generic data %*ph failed: %zd\n",
> +			(int)size, payload, ret);
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(mipi_dsi_generic_write_raw_multi);
> +
>   /**
>    * mipi_dsi_generic_read() - receive data using a generic read packet
>    * @dsi: DSI peripheral device
>    * @params: buffer containing the request parameters
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index 71d121aeef24..fb23f4e3b94e 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -287,8 +287,10 @@ ssize_t mipi_dsi_generic_write(struct mipi_dsi_device *dsi, const void *payload,
>   int mipi_dsi_generic_write_chatty(struct mipi_dsi_device *dsi,
>   				  const void *payload, size_t size);
>   void mipi_dsi_generic_write_multi(struct mipi_dsi_multi_context *ctx,
>   				  const void *payload, size_t size);
> +ssize_t mipi_dsi_generic_write_raw_multi(struct mipi_dsi_multi_context *ctx, u8 type,
> +				    const void *payload, size_t size);
>   ssize_t mipi_dsi_generic_read(struct mipi_dsi_device *dsi, const void *params,
>   			      size_t num_params, void *data, size_t size);
>   
>   #define mipi_dsi_msleep(ctx, delay)	\
> @@ -432,8 +434,22 @@ void mipi_dsi_dcs_set_tear_on_multi(struct mipi_dsi_multi_context *ctx,
>   		static const u8 d[] = { cmd, seq };                     \
>   		mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
>   	} while (0)
>   
> +/**
> + * mipi_dsi_dcs_write_long_multi - transmit a DCS long command with payload
> + * @ctx: Context for multiple DSI transactions
> + * @cmd: Commands
> + * @seq: buffer containing data to be transmitted
> + */
> +#define mipi_dsi_dcs_write_long_multi(ctx, cmd, seq...)                    \
> +	do {                                                               \
> +		static const u8 d[] = { cmd, seq };                        \
> +		mipi_dsi_generic_write_raw_multi(ctx,                      \
> +						  MIPI_DSI_DCS_LONG_WRITE, \
> +						  d, ARRAY_SIZE(d));       \
> +	} while (0)
> +
>   /**
>    * struct mipi_dsi_driver - DSI driver
>    * @driver: device driver model driver
>    * @probe: callback for device binding
> 
> -- 
> 2.45.0
>