Allow data-only i2c transfers
Modified the i2c_imx driver to support data-only transfers, without command byte. This allows to construct more complex i2c transfers and support non genuine devices like Atmel ATxx secure memory, where the master reads data after a write command. Signed-off-by: Rosen Kolev <rosen.kolev@amk-drives.bg> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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@ -314,6 +314,7 @@ static int i2c_imx_write(struct i2c_adapter *adapter, struct i2c_msg *msgs)
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void __iomem *base = i2c_imx->base;
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int i, result;
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if ( !(msgs->flags & I2C_M_DATA_ONLY) ) {
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dev_dbg(adapter->dev,
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"<%s> write slave address: addr=0x%02x\n",
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__func__, msgs->addr << 1);
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@ -327,6 +328,7 @@ static int i2c_imx_write(struct i2c_adapter *adapter, struct i2c_msg *msgs)
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result = i2c_imx_acked(adapter);
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if (result)
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return result;
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}
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/* write data */
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for (i = 0; i < msgs->len; i++) {
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@ -352,13 +354,14 @@ static int i2c_imx_read(struct i2c_adapter *adapter, struct i2c_msg *msgs)
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int i, result;
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unsigned int temp;
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/* clear IIF */
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writeb(0x0, base + IMX_I2C_I2SR);
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if ( !(msgs->flags & I2C_M_DATA_ONLY) ) {
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dev_dbg(adapter->dev,
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"<%s> write slave address: addr=0x%02x\n",
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__func__, (msgs->addr << 1) | 0x01);
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/* clear IIF */
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writeb(0x0, base + IMX_I2C_I2SR);
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/* write slave address */
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writeb((msgs->addr << 1) | 0x01, base + IMX_I2C_I2DR);
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@ -368,6 +371,7 @@ static int i2c_imx_read(struct i2c_adapter *adapter, struct i2c_msg *msgs)
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result = i2c_imx_acked(adapter);
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if (result)
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return result;
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}
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/* setup bus to read data */
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temp = readb(base + IMX_I2C_I2CR);
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@ -428,7 +432,7 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
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/* read/write data */
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for (i = 0; i < num; i++) {
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if (i) {
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if (i && !(msgs[i].flags & I2C_M_DATA_ONLY)) {
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temp = readb(base + IMX_I2C_I2CR);
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temp |= I2CR_RSTA;
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writeb(temp, base + IMX_I2C_I2CR);
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@ -30,6 +30,7 @@ struct i2c_platform_data {
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#define I2C_NAME_SIZE 20
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#define I2C_M_RD 0x0001 /* read data, from slave to master */
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#define I2C_M_DATA_ONLY 0x0002 /* transfer data bytes only */
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#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
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#define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */
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