From: Christian Eggers ceggers@arri.de
commit 61e6fe59ede155881a622f5901551b1cc8748f6a upstream.
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 Acked-by: Oleksij Rempel o.rempel@pengutronix.de Cc: stable@vger.kernel.org # Requires trivial backporting, simple remove # the 3rd argument from the calls to # i2c_imx_bus_busy(). Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/busses/i2c-imx.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- 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_ /* 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_i */ 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_s 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: