On 07/22/2014 09:12 AM, Thierry Reding wrote:
> From: Thierry Reding <treding at nvidia.com>
>
> 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().
>
> Also update the S6E8AA0 panel driver (the only user of this API) to
> adapt to this new API.
I do not agree with that. DCS read and write are not symmetrical by design:
- write just sends data,
- read sends data then reads response.
Forcing API to be symmetrical complicates the implementation without real gain.
Regards
Andrzej
>
> Signed-off-by: Thierry Reding <treding at nvidia.com>
> ---
> drivers/gpu/drm/drm_mipi_dsi.c | 45
> ++++++++++++++++++++++++-----------
> drivers/gpu/drm/panel/panel-s6e8aa0.c | 4 ++--
> include/drm/drm_mipi_dsi.h | 4 ++--
> 3 files changed, 35 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> index 6aa6a9e95570..bbab06ef80c9 100644
> --- a/drivers/gpu/drm/drm_mipi_dsi.c
> +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> @@ -201,29 +201,41 @@ EXPORT_SYMBOL(mipi_dsi_detach);
> /**
> * mipi_dsi_dcs_write - send DCS write command
> * @dsi: DSI device
> - * @data: pointer to the command followed by parameters
> - * @len: length of @data
> + * @cmd: DCS command
> + * @data: pointer to the command payload
> + * @len: payload length
> */
> -ssize_t mipi_dsi_dcs_write(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)
> {
> const struct mipi_dsi_host_ops *ops = dsi->host->ops;
> - struct mipi_dsi_msg msg = {
> - .channel = dsi->channel,
> - .tx_buf = data,
> - .tx_len = len
> - };
> + struct mipi_dsi_msg msg;
> + ssize_t err;
> + u8 *tx;
>
> if (!ops || !ops->transfer)
> return -ENOSYS;
>
> + if (len > 0) {
> + tx = kmalloc(1 + len, GFP_KERNEL);
> + if (!tx)
> + return -ENOMEM;
> +
> + tx[0] = cmd;
> + memcpy(tx + 1, data, len);
> + } else {
> + tx = &cmd;
> + }
> +
> + msg.channel = dsi->channel;
> + msg.tx_len = 1 + len;
> + msg.tx_buf = tx;
> +
> switch (len) {
> case 0:
> - return -EINVAL;
> - case 1:
> msg.type = MIPI_DSI_DCS_SHORT_WRITE;
> break;
> - case 2:
> + case 1:
> msg.type = MIPI_DSI_DCS_SHORT_WRITE_PARAM;
> break;
> default:
> @@ -231,14 +243,19 @@ ssize_t mipi_dsi_dcs_write(struct mipi_dsi_device *dsi,
> const void *data,
> break;
> }
>
> - return ops->transfer(dsi->host, &msg);
> + err = ops->transfer(dsi->host, &msg);
> +
> + 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
> + * @cmd: DCS command
> * @data: pointer to read buffer
> * @len: length of @data
> *
> diff --git a/drivers/gpu/drm/panel/panel-s6e8aa0.c
> b/drivers/gpu/drm/panel/panel-s6e8aa0.c
> index 5502ef6bc074..d39bee36816c 100644
> --- a/drivers/gpu/drm/panel/panel-s6e8aa0.c
> +++ b/drivers/gpu/drm/panel/panel-s6e8aa0.c
> @@ -130,7 +130,7 @@ static int s6e8aa0_clear_error(struct s6e8aa0 *ctx)
> return ret;
> }
>
> -static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const void *data, size_t
> len)
> +static void s6e8aa0_dcs_write(struct s6e8aa0 *ctx, const u8 *data, size_t
> len)
> {
> struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
> ssize_t ret;
> @@ -138,7 +138,7 @@ 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(dsi, data[0], data + 1, len - 1);
> if (ret < 0) {
> dev_err(ctx->dev, "error %zd writing dcs seq: %*ph\n", ret, len,
> data);
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index 7b5e1a9244e1..bea181121e8b 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);
> -ssize_t mipi_dsi_dcs_write(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);
>
