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SubjectRe: [PATCH] drm/bridge/synopsys: dsi: Add read feature
Date
Hi Andrzej,

And many thanks
Philippe :-)

On 02/05/2018 11:07 AM, Andrzej Hajda wrote:
> On 04.02.2018 22:31, Philippe Cornu wrote:
>> This patch adds the DCS/GENERIC DSI read feature.
>>
>> Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
>
> Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
>
> If there will be no objections I will merge it at the end of the week.
>
>  --
> Regards
> Andrzej
>
>> ---
>> Extra notes:
>> DSI read tests have been performed with DCS & GENERIC, short & long
>> commands, on two different panels.
>> The maximum fifo size (32*32-bit = 128 bytes on stm32) has been
>> verified too.
>>
>> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 +++++++++++++++++++++------
>> 1 file changed, 45 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> index e9422d05e897..65aeb3f78b48 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
>> @@ -397,18 +397,46 @@ static int dw_mipi_dsi_write(struct dw_mipi_dsi *dsi,
>> return dw_mipi_dsi_gen_pkt_hdr_write(dsi, le32_to_cpu(word));
>> }
>>
>> +static int dw_mipi_dsi_read(struct dw_mipi_dsi *dsi,
>> + const struct mipi_dsi_msg *msg)
>> +{
>> + int i, j, ret, len = msg->rx_len;
>> + u8 *buf = msg->rx_buf;
>> + u32 val;
>> +
>> + /* Wait end of the read operation */
>> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_RD_CMD_BUSY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> + if (ret) {
>> + dev_err(dsi->dev, "Timeout during read operation\n");
>> + return ret;
>> + }
>> +
>> + for (i = 0; i < len; i += 4) {
>> + /* Read fifo must not be empty before all bytes are read */
>> + ret = readl_poll_timeout(dsi->base + DSI_CMD_PKT_STATUS,
>> + val, !(val & GEN_PLD_R_EMPTY),
>> + 1000, CMD_PKT_STATUS_TIMEOUT_US);
>> + if (ret) {
>> + dev_err(dsi->dev, "Read payload FIFO is empty\n");
>> + return ret;
>> + }
>> +
>> + val = dsi_read(dsi, DSI_GEN_PLD_DATA);
>> + for (j = 0; j < 4 && j + i < len; j++)
>> + buf[i + j] = val >> (8 * j);
>> + }
>> +
>> + return ret;
>> +}
>> +
>> static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>> const struct mipi_dsi_msg *msg)
>> {
>> struct dw_mipi_dsi *dsi = host_to_dsi(host);
>> struct mipi_dsi_packet packet;
>> - int ret;
>> -
>> - if (msg->rx_buf || msg->rx_len) {
>> - /* TODO dw drv improvements: implement read feature */
>> - dev_warn(dsi->dev, "read operations not yet implemented\n");
>> - return -EINVAL;
>> - }
>> + int ret, nb_bytes;
>>
>> ret = mipi_dsi_create_packet(&packet, msg);
>> if (ret) {
>> @@ -422,12 +450,16 @@ static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
>> if (ret)
>> return ret;
>>
>> - /*
>> - * TODO Only transmitted size is returned as actual driver does
>> - * not support dcs/generic reads. Please update return value when
>> - * delivering the read feature.
>> - */
>> - return packet.size;
>> + if (msg->rx_buf && msg->rx_len) {
>> + ret = dw_mipi_dsi_read(dsi, msg);
>> + if (ret)
>> + return ret;
>> + nb_bytes = msg->rx_len;
>> + } else {
>> + nb_bytes = packet.size;
>> + }
>> +
>> + return nb_bytes;
>> }
>>
>> static const struct mipi_dsi_host_ops dw_mipi_dsi_host_ops = {
>
>
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