Support repeated start mode. Don't send a STOP if it's part
of a group of transactions (e.g. write of register address followed by a
register value read).
Signed-off-by: Kelvin Lawson <klawson@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-qcom-cci.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
index 143e44d..1032e16 100644
--- a/drivers/i2c/busses/i2c-qcom-cci.c
+++ b/drivers/i2c/busses/i2c-qcom-cci.c
@@ -512,7 +512,8 @@ static int cci_i2c_read(struct cci *cci, u16 addr, u8 *buf, u16 len)
return 0;
}
-static int cci_i2c_write(struct cci *cci, u16 addr, u8 *buf, u16 len)
+static int cci_i2c_write(struct cci *cci, u16 addr, u8 *buf, u16 len,
+ int disable_stop)
{
u8 master = 0;
u8 queue = QUEUE_0;
@@ -533,7 +534,8 @@ static int cci_i2c_write(struct cci *cci, u16 addr, u8 *buf, u16 len)
writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
i = 0;
- load[i++] = CCI_I2C_WRITE | len << 4;
+ load[i++] = (disable_stop ? CCI_I2C_WRITE_DISABLE_P : CCI_I2C_WRITE)
+ | len << 4;
for (j = 0; j < len; j++)
load[i++] = buf[j];
@@ -557,6 +559,13 @@ static int cci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
struct cci *cci = i2c_get_adapdata(adap);
int i;
int ret = 0;
+ int disable_stop = 0;
+
+ /*
+ * Use repeated start (no STOP bit on writes) if this is a group of
+ * transactions (e.g. write register address followed by read data).
+ */
+ disable_stop = num > 1;
for (i = 0; i < num; i++) {
if (msgs[i].flags & I2C_M_RD)
--
2.7.4
