6.6-stable review patch. If anyone has any objections, please let me know.
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From: Francesco Dolcini francesco.dolcini@toradex.com
commit 32c4514455b2b8fde506f8c0962f15c7e4c26f1d upstream.
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@vger.kernel.org Signed-off-by: Francesco Dolcini francesco.dolcini@toradex.com Reviewed-by: Neil Armstrong neil.armstrong@linaro.org Link: https://lore.kernel.org/r/20240926141246.48282-1-francesco@dolcini.it Signed-off-by: Neil Armstrong neil.armstrong@linaro.org Link: https://patchwork.freedesktop.org/patch/msgid/20240926141246.48282-1-frances... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
--- 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_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_transfe } }
- /* start transfer */ - tc358768_write(priv, TC358768_DSICMD_TX, 1); + tc358768_dsicmd_tx(priv);
ret = tc358768_clear_error(priv); if (ret)