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Commit e5da5a2a authored by Christian Eggers's avatar Christian Eggers Committed by Greg Kroah-Hartman
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i2c: imx: Don't generate STOP condition if arbitration has been lost 



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: default avatarChristian Eggers <ceggers@arri.de>
Tested (not extensively) on Vybrid VF500 (Toradex VF50):
Tested-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: default avatarOleksij 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: default avatarWolfram Sang <wsa@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ba54b13c

drivers/i2c/busses/i2c-imx.c

+10 −2
Original line number Diff line number Diff line
@@ -557,6 +557,8 @@ 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;
@@ -722,8 +724,11 @@ 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);

		if (!i2c_imx->stopped)

			i2c_imx_bus_busy(i2c_imx, 0);

	} else {

		/*
@@ -847,8 +852,11 @@ 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);

				if (!i2c_imx->stopped)

					i2c_imx_bus_busy(i2c_imx, 0);

			} else {

				/*