| Message ID | 20201007084524.10835-4-ceggers@arri.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | i2c: imx: Fix handling of arbitration loss | expand |
On Wed, Oct 07, 2020 at 10:45:24AM +0200, Christian Eggers wrote: > If arbitration is lost, the master automatically changes to slave mode. > I2SR_IBB may or may not be reset by hardware. Raising a STOP condition > by resetting I2CR_MSTA has no effect and will not clear I2SR_IBB. > > So calling i2c_imx_bus_busy() is not required and would busy-wait until > timeout. > > Signed-off-by: Christian Eggers <ceggers@arri.de> > Tested (not extensively) on Vybrid VF500 (Toradex VF50): > Tested-by: Krzysztof Kozlowski <krzk@kernel.org> > Cc: stable@vger.kernel.org # Requires trivial backporting, simple remove > # the 3rd argument from the calls to > # i2c_imx_bus_busy(). Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Thank you! > --- > drivers/i2c/busses/i2c-imx.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index 63575af41c09..5d8a79319b2b 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -615,6 +615,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic) > /* Stop I2C transaction */ > dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); > temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + if (!(temp & I2CR_MSTA)) > + i2c_imx->stopped = 1; > temp &= ~(I2CR_MSTA | I2CR_MTX); > if (i2c_imx->dma) > temp &= ~I2CR_DMAEN; > @@ -778,9 +780,12 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, > */ > dev_dbg(dev, "<%s> clear MSTA\n", __func__); > temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + if (!(temp & I2CR_MSTA)) > + i2c_imx->stopped = 1; > temp &= ~(I2CR_MSTA | I2CR_MTX); > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > - i2c_imx_bus_busy(i2c_imx, 0, false); > + if (!i2c_imx->stopped) > + i2c_imx_bus_busy(i2c_imx, 0, false); > } else { > /* > * For i2c master receiver repeat restart operation like: > @@ -905,9 +910,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, > dev_dbg(&i2c_imx->adapter.dev, > "<%s> clear MSTA\n", __func__); > temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); > + if (!(temp & I2CR_MSTA)) > + i2c_imx->stopped = 1; > temp &= ~(I2CR_MSTA | I2CR_MTX); > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); > - i2c_imx_bus_busy(i2c_imx, 0, atomic); > + if (!i2c_imx->stopped) > + i2c_imx_bus_busy(i2c_imx, 0, atomic); > } else { > /* > * For i2c master receiver repeat restart operation like: > -- > Christian Eggers > Embedded software developer > > Arnold & Richter Cine Technik GmbH & Co. Betriebs KG > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918 > Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 > Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 63575af41c09..5d8a79319b2b 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -615,6 +615,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic) /* Stop I2C transaction */ dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); if (i2c_imx->dma) temp &= ~I2CR_DMAEN; @@ -778,9 +780,12 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, */ dev_dbg(dev, "<%s> clear MSTA\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - i2c_imx_bus_busy(i2c_imx, 0, false); + if (!i2c_imx->stopped) + i2c_imx_bus_busy(i2c_imx, 0, false); } else { /* * For i2c master receiver repeat restart operation like: @@ -905,9 +910,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, dev_dbg(&i2c_imx->adapter.dev, "<%s> clear MSTA\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - i2c_imx_bus_busy(i2c_imx, 0, atomic); + if (!i2c_imx->stopped) + i2c_imx_bus_busy(i2c_imx, 0, atomic); } else { /* * For i2c master receiver repeat restart operation like: