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i2c: imx: Don't generate STOP condition if arbitration has been lost 

commit 61e6fe59ed 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>
5.4-rM2-2.2.x-imx-squashed
Christian Eggers 2020-10-09 13:03:20 +02:00 committed by Greg Kroah-Hartman
parent 73948ab9f2
commit ed201cb54d
1 changed files with 10 additions and 2 deletions
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12
drivers/i2c/busses/i2c-imx.c
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@ -567,6 +567,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
/* 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;
@ -732,9 +734,12 @@ 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);
if (!i2c_imx->stopped)
i2c_imx_bus_busy(i2c_imx, 0);
} else {
/*
* For i2c master receiver repeat restart operation like:
@ -857,9 +862,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bo
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);
if (!i2c_imx->stopped)
i2c_imx_bus_busy(i2c_imx, 0);
} else {
/*
* For i2c master receiver repeat restart operation like: