On Wed, Jul 03, 2019 at 05:47:32PM +0100, Mans Rullgard wrote:
> Add support for the I2C_M_STOP flag to the i2c-imx driver. This allows
> devices requiring a stop between messages to work with this controller.
>
> Signed-off-by: Mans Rullgard <mans@xxxxxxxxx>
The problem with this driver is that it is unmaintained, sadly :( I'll
cc some people who might be interested...
> ---
> drivers/i2c/busses/i2c-imx.c | 26 ++++++++++++++++++++++----
> 1 file changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 7bd409eaf0ac..a7f801bb5dc9 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -908,10 +908,17 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
>
> /* read/write data */
> for (i = 0; i < num; i++) {
> - if (i == num - 1)
> - is_lastmsg = true;
> + if (is_lastmsg) {
> + /* previous message had I2C_M_STOP flag set */
> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> + temp |= I2CR_MSTA;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> + result = i2c_imx_bus_busy(i2c_imx, 1);
> + if (result)
> + goto fail0;
> + }
>
> - if (i) {
> + if (i && !is_lastmsg) {
> dev_dbg(&i2c_imx->adapter.dev,
> "<%s> repeated start\n", __func__);
> temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> @@ -921,6 +928,10 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
> if (result)
> goto fail0;
> }
> +
> + if (i == num - 1 || (msgs[i].flags & I2C_M_STOP))
> + is_lastmsg = true;
> +
> dev_dbg(&i2c_imx->adapter.dev,
> "<%s> transfer message: %d\n", __func__, i);
> /* write/read data */
> @@ -948,6 +959,13 @@ static int i2c_imx_xfer(struct i2c_adapter *adapter,
> result = i2c_imx_dma_write(i2c_imx, &msgs[i]);
> else
> result = i2c_imx_write(i2c_imx, &msgs[i]);
> +
> + if (msgs[i].flags & I2C_M_STOP) {
> + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
> + temp &= ~I2CR_MSTA;
> + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
> + i2c_imx_bus_busy(i2c_imx, 0);
> + }
> }
> if (result)
> goto fail0;
> @@ -1034,7 +1052,7 @@ static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
>
> static u32 i2c_imx_func(struct i2c_adapter *adapter)
> {
> - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
> + return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_SMBUS_EMUL
> | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
> }
>
> --
> 2.22.0
>
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