Hello Neil,
On Wed, Oct 23, 2024 at 10:03:20AM +0200, Neil Armstrong wrote:
> On 26/09/2024 16:12, Francesco Dolcini wrote:
> > From: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
> >
> > Wait for the command transmission to be completed in the DSI transfer
> > function polling for the dc_start bit to go back to idle state after the
> > transmission is started.
> >
> > This is documented in the datasheet and failures to do so lead to
> > commands corruption.
> >
> > Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>
> > ---
> > drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++--
> > 1 file changed, 19 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> > index 0e8813278a2f..bb1750a3dab0 100644
> > --- a/drivers/gpu/drm/bridge/tc358768.c
> > +++ b/drivers/gpu/drm/bridge/tc358768.c
> > @@ -125,6 +125,9 @@
> > #define TC358768_DSI_CONFW_MODE_CLR (6 << 29)
> > #define TC358768_DSI_CONFW_ADDR_DSI_CONTROL (0x3 << 24)
> > +/* TC358768_DSICMD_TX (0x0600) register */
> > +#define TC358768_DSI_CMDTX_DC_START BIT(0)
> > +
> > static const char * const tc358768_supplies[] = {
> > "vddc", "vddmipi", "vddio"
> > };
> > @@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
> > tc358768_write(priv, reg, tmp);
> > }
> > +static void tc358768_dsicmd_tx(struct tc358768_priv *priv)
> > +{
> > + u32 val;
> > +
> > + /* start transfer */
> > + tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START);
> > + if (priv->error)
> > + return;
> > +
> > + /* wait transfer completion */
> > + priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val,
> > + (val & TC358768_DSI_CMDTX_DC_START) == 0,
> > + 100, 100000);
> > +}
> > +
> > static int tc358768_sw_reset(struct tc358768_priv *priv)
> > {
> > /* Assert Reset */
> > @@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host,
> > }
> > }
> > - /* start transfer */
> > - tc358768_write(priv, TC358768_DSICMD_TX, 1);
> > + tc358768_dsicmd_tx(priv);
> > ret = tc358768_clear_error(priv);
> > if (ret)
>
> Look good, I'll leave it here a few days if someone has comments
Just a gently reminder, thanks
> Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Francesco
