On Wed, 14 Dec 2022 at 13:59, Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote:
>
> The function it66121_wait_ddc_ready() would previously read the status
> register until "true", which means it never actually polled anything and
> would just read the register once.
>
> Now, it will properly wait until the DDC hardware is ready or until it
> reported an error.
>
> The 'busy' variable was also renamed to 'error' since these bits are set
> on error and not when the DDC hardware is busy.
>
> Since the DDC ready function is now working properly, the msleep(20) can
> be removed.
>
> Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/ite-it66121.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
> index 0a4fdfd7af44..bfb9c87a7019 100644
> --- a/drivers/gpu/drm/bridge/ite-it66121.c
> +++ b/drivers/gpu/drm/bridge/ite-it66121.c
> @@ -440,15 +440,17 @@ static int it66121_configure_afe(struct it66121_ctx *ctx,
> static inline int it66121_wait_ddc_ready(struct it66121_ctx *ctx)
> {
> int ret, val;
> - u32 busy = IT66121_DDC_STATUS_NOACK | IT66121_DDC_STATUS_WAIT_BUS |
> - IT66121_DDC_STATUS_ARBI_LOSE;
> + u32 error = IT66121_DDC_STATUS_NOACK | IT66121_DDC_STATUS_WAIT_BUS |
> + IT66121_DDC_STATUS_ARBI_LOSE;
> + u32 done = IT66121_DDC_STATUS_TX_DONE;
>
> - ret = regmap_read_poll_timeout(ctx->regmap, IT66121_DDC_STATUS_REG, val, true,
> - IT66121_EDID_SLEEP_US, IT66121_EDID_TIMEOUT_US);
> + ret = regmap_read_poll_timeout(ctx->regmap, IT66121_DDC_STATUS_REG, val,
> + val & (error | done), IT66121_EDID_SLEEP_US,
> + IT66121_EDID_TIMEOUT_US);
> if (ret)
> return ret;
>
> - if (val & busy)
> + if (val & error)
> return -EAGAIN;
>
> return 0;
> @@ -582,9 +584,6 @@ static int it66121_get_edid_block(void *context, u8 *buf,
> offset += cnt;
> remain -= cnt;
>
> - /* Per programming manual, sleep here before emptying the FIFO */
> - msleep(20);
> -
> ret = it66121_wait_ddc_ready(ctx);
> if (ret)
> return ret;
> --
> 2.35.1
>
Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxx>
