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i2c: imx: Don't generate STOP condition if arbitration has been lost
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>
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1 changed files with 10 additions and 2 deletions
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@ -615,6 +615,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic)
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/* Stop I2C transaction */
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dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
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temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
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if (!(temp & I2CR_MSTA))
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i2c_imx->stopped = 1;
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temp &= ~(I2CR_MSTA | I2CR_MTX);
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if (i2c_imx->dma)
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temp &= ~I2CR_DMAEN;
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@ -778,9 +780,12 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx,
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*/
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dev_dbg(dev, "<%s> clear MSTA\n", __func__);
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temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
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if (!(temp & I2CR_MSTA))
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i2c_imx->stopped = 1;
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temp &= ~(I2CR_MSTA | I2CR_MTX);
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imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
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i2c_imx_bus_busy(i2c_imx, 0, false);
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if (!i2c_imx->stopped)
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i2c_imx_bus_busy(i2c_imx, 0, false);
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} else {
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/*
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* For i2c master receiver repeat restart operation like:
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@ -905,9 +910,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs,
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dev_dbg(&i2c_imx->adapter.dev,
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"<%s> clear MSTA\n", __func__);
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temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
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if (!(temp & I2CR_MSTA))
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i2c_imx->stopped = 1;
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temp &= ~(I2CR_MSTA | I2CR_MTX);
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imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
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i2c_imx_bus_busy(i2c_imx, 0, atomic);
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if (!i2c_imx->stopped)
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i2c_imx_bus_busy(i2c_imx, 0, atomic);
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} else {
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/*
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* For i2c master receiver repeat restart operation like:
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