On 07/22/2014 01:20 PM, Daniel Vetter wrote:
> On Tue, Jul 22, 2014 at 09:12:20AM +0200, 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.
>>
>> Signed-off-by: Thierry Reding <treding at nvidia.com>
> Given the patterns established by other sideband subsystesm like i2c or
> the dp aux helpers we have in drm I think this is going into the right
> direction. Also, this seems to match somewhat the style we have in our
> hand-rolled intel dsi implementation. So I think this makes sense.
Could you point me out the patterns you are referring to.
Regarding intel dsi implementation I have found in intel_dsi_cmd.h:
int dsi_vc_dcs_write(struct intel_dsi *intel_dsi, int channel,
const u8 *data, int len);
int dsi_vc_dcs_read(struct intel_dsi *intel_dsi, int channel,
u8 dcs_cmd, u8 *buf, int buflen);
This is the same approach as in the current drm mipi, no forced symmetry.
There are also helpers for simple DCS commands: dsi_vc_dcs_write_[01],
but they
are using dsi_vc_dcs_write internally, which seems to me more reasonable.
Regards
Andrzej
>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>> ---
>> 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);
>>
>> --
>> 2.0.1
>>
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