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Message-Id: <20190227182137.12100-1-mans@mansr.com>
Date: Wed, 27 Feb 2019 18:21:37 +0000
From: Mans Rullgard <mans@...sr.com>
To: linux-i2c@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH] i2c: imx: add support for I2C_M_STOP flag
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@...sr.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 c406700789e1..43b4d5bc2196 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;
}
--
2.20.1
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