| Message ID | 20180115173357.31067-2-a.hajda@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 15.01.2018 18:33, Andrzej Hajda wrote: > Chip has known bug which causes I2C client state machine to frequently > enter non-idle mode after chip reset. Let's ask I2C adapter to perform > bus recovery to mitigate this bug. > > Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> > --- > drivers/gpu/drm/bridge/sil-sii8620.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c > index 86789f8918a4..db93e5e0497c 100644 > --- a/drivers/gpu/drm/bridge/sil-sii8620.c > +++ b/drivers/gpu/drm/bridge/sil-sii8620.c > @@ -978,6 +978,8 @@ static int sii8620_hw_off(struct sii8620 *ctx) > > static void sii8620_hw_reset(struct sii8620 *ctx) > { > + struct i2c_client *i2c = to_i2c_client(ctx->dev); > + > usleep_range(10000, 20000); > gpiod_set_value(ctx->gpio_reset, 0); > usleep_range(5000, 20000); > @@ -985,6 +987,9 @@ static void sii8620_hw_reset(struct sii8620 *ctx) > usleep_range(10000, 20000); > gpiod_set_value(ctx->gpio_reset, 0); > msleep(300); > + > + /* I2C bus recovery prevents I2C errors due to known bug in the chip */ > + i2c_recover_bus(i2c->adapter); > } > > static void sii8620_cbus_reset(struct sii8620 *ctx) I have just posted patch which deals with the problem directly in i2c adapter, so this patch can be dropped[1]. [1]: https://marc.info/?l=linux-i2c&m=151696860906805 Regards Andrzej
diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c index 86789f8918a4..db93e5e0497c 100644 --- a/drivers/gpu/drm/bridge/sil-sii8620.c +++ b/drivers/gpu/drm/bridge/sil-sii8620.c @@ -978,6 +978,8 @@ static int sii8620_hw_off(struct sii8620 *ctx) static void sii8620_hw_reset(struct sii8620 *ctx) { + struct i2c_client *i2c = to_i2c_client(ctx->dev); + usleep_range(10000, 20000); gpiod_set_value(ctx->gpio_reset, 0); usleep_range(5000, 20000); @@ -985,6 +987,9 @@ static void sii8620_hw_reset(struct sii8620 *ctx) usleep_range(10000, 20000); gpiod_set_value(ctx->gpio_reset, 0); msleep(300); + + /* I2C bus recovery prevents I2C errors due to known bug in the chip */ + i2c_recover_bus(i2c->adapter); } static void sii8620_cbus_reset(struct sii8620 *ctx)
Chip has known bug which causes I2C client state machine to frequently enter non-idle mode after chip reset. Let's ask I2C adapter to perform bus recovery to mitigate this bug. Signed-off-by: Andrzej Hajda <a.hajda@samsung.com> --- drivers/gpu/drm/bridge/sil-sii8620.c | 5 +++++ 1 file changed, 5 insertions(+)