Commit 960dd616 authored by Thierry Reding's avatar Thierry Reding
Browse files

drm/dsi: Make mipi_dsi_dcs_{read,write}() symmetrical 



Currently the mipi_dsi_dcs_write() function requires the DCS command
byte to be embedded within the write buffer whereas mipi_dsi_dcs_read()
has a separate parameter. Make them more symmetrical by adding an extra
command parameter to mipi_dsi_dcs_write().

The S6E8AA0 driver relies on the old asymmetric API and there's concern
that moving to the new API may be less efficient. Provide a new function
with the old semantics for those cases and make the S6E8AA0 driver use
it instead.

Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent 9eb491f3

drivers/gpu/drm/drm_mipi_dsi.c

+65 −12
Original line number Diff line number Diff line
@@ -333,13 +333,19 @@ int mipi_dsi_create_packet(struct mipi_dsi_packet *packet, 
EXPORT_SYMBOL(mipi_dsi_create_packet);



/**

 * mipi_dsi_dcs_write - send DCS write command

 * @dsi: DSI device

 * @data: pointer to the command followed by parameters

 * @len: length of @data

 * mipi_dsi_dcs_write_buffer() - transmit a DCS command with payload

 * @dsi: DSI peripheral device

 * @data: buffer containing data to be transmitted

 * @len: size of transmission buffer

 *

 * This function will automatically choose the right data type depending on

 * the command payload length.

 *

 * Return: The number of bytes successfully transmitted or a negative error

 * code on failure.

 */

ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,

			    size_t len)

ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,

				  const void *data, size_t len)

{

	struct mipi_dsi_msg msg = {

		.channel = dsi->channel,
@@ -350,12 +356,15 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data, 
	switch (len) {

	case 0:

		return -EINVAL;



	case 1:

		msg.type = MIPI_DSI_DCS_SHORT_WRITE;

		break;



	case 2:

		msg.type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;

		break;



	default:

		msg.type = MIPI_DSI_DCS_LONG_WRITE;

		break;
@@ -363,16 +372,60 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data, 


	return mipi_dsi_device_transfer(dsi, &msg);

}

EXPORT_SYMBOL(mipi_dsi_dcs_write_buffer);



/**

 * mipi_dsi_dcs_write() - send DCS write command

 * @dsi: DSI peripheral device

 * @cmd: DCS command

 * @data: buffer containing the command payload

 * @len: command payload length

 *

 * This function will automatically choose the right data type depending on

 * the command payload length.

 *

 * Return: The number of bytes successfully transmitted or a negative error

 * code on failure.

 */

ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,

			   const void *data, size_t len)

{

	ssize_t err;

	size_t size;

	u8 *tx;



	if (len > 0) {

		size = 1 + len;



		tx = kmalloc(size, GFP_KERNEL);

		if (!tx)

			return -ENOMEM;



		/* concatenate the DCS command byte and the payload */

		tx[0] = cmd;

		memcpy(&tx[1], data, len);

	} else {

		tx = &cmd;

		size = 1;

	}



	err = mipi_dsi_dcs_write_buffer(dsi, tx, size);



	if (len > 0)

		kfree(tx);



	return err;

}

EXPORT_SYMBOL(mipi_dsi_dcs_write);



/**

 * mipi_dsi_dcs_read - send DCS read request command

 * @dsi: DSI device

 * @cmd: DCS read command

 * @data: pointer to read buffer

 * @len: length of @data

 * mipi_dsi_dcs_read() - send DCS read request command

 * @dsi: DSI peripheral device

 * @cmd: DCS command

 * @data: buffer in which to receive data

 * @len: size of receive buffer

 *

 * Function returns number of read bytes or error code.

 * Return: The number of bytes read or a negative error code on failure.

 */

ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,

			  size_t len)

drivers/gpu/drm/panel/panel-s6e8aa0.c

+1 −1
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const void *data, size_t len) 
	if (ctx->error < 0)

		return;



	ret = mipi_dsi_dcs_write(dsi, data, len);

	ret = mipi_dsi_dcs_write_buffer(dsi, data, len);

	if (ret < 0) {

		dev_err(ctx->dev, "error %zd writing dcs seq: %*ph\n", ret,

			(int)len, data);

include/drm/drm_mipi_dsi.h

+4 −2
Original line number Diff line number Diff line
@@ -153,8 +153,10 @@ static inline struct mipi_dsi_device *to_mipi_dsi_device(struct device *dev) 


int mipi_dsi_attach(struct mipi_dsi_device *dsi);

int mipi_dsi_detach(struct mipi_dsi_device *dsi);

ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, const void *data,

			    size_t len);

ssize_t mipi_dsi_dcs_write_buffer(struct mipi_dsi_device *dsi,

				  const void *data, size_t len);

ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi, u8 cmd,

			   const void *data, size_t len);

ssize_t mipi_dsi_dcs_read(struct mipi_dsi_device *dsi, u8 cmd, void *data,

			  size_t len);

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