[PATCH] i2c: imx: add support for I2C_M_STOP flag
Mans Rullgard
mans at mansr.com
Thu Jul 6 05:57:29 PDT 2023
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 at mansr.com>
---
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 42189a5f2905..f59d086688ff 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1262,10 +1262,17 @@ static int i2c_imx_xfer_common(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, atomic);
+ 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);
@@ -1275,6 +1282,10 @@ static int i2c_imx_xfer_common(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 */
@@ -1304,6 +1315,13 @@ static int i2c_imx_xfer_common(struct i2c_adapter *adapter,
result = i2c_imx_dma_write(i2c_imx, &msgs[i]);
else
result = i2c_imx_write(i2c_imx, &msgs[i], atomic);
+
+ 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, atomic);
+ }
}
if (result)
goto fail0;
@@ -1425,7 +1443,7 @@ 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;
}
--
2.41.0
More information about the linux-arm-kernel
mailing list