[PATCH 4.14 077/189] i2c: sprd: Fix the i2c count issue

Greg Kroah-Hartman
2018-06-18T08:33:37Z

From: Baolin Wang <baolin.wang@linaro.org>

[ Upstream commit 2a010461207cc96bee5ab81748325dec1972976f ]

We found the I2C controller count register is unreliable sometimes,
that will cause I2C to lose data. Thus we can read the data count
from 'i2c_dev->count' instead of the I2C controller count register.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/i2c/busses/i2c-sprd.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/i2c/busses/i2c-sprd.c
+++ b/drivers/i2c/busses/i2c-sprd.c
@@ -368,13 +368,12 @@ static irqreturn_t sprd_i2c_isr_thread(i
struct sprd_i2c *i2c_dev = dev_id;
struct i2c_msg *msg = i2c_dev->msg;
bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
- u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
u32 i2c_tran;

if (msg->flags & I2C_M_RD)
i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
else
- i2c_tran = i2c_count;
+ i2c_tran = i2c_dev->count;

/*
* If we got one ACK from slave when writing data, and we did not
@@ -412,14 +411,13 @@ static irqreturn_t sprd_i2c_isr(int irq,
{
struct sprd_i2c *i2c_dev = dev_id;
struct i2c_msg *msg = i2c_dev->msg;
- u32 i2c_count = readl(i2c_dev->base + I2C_COUNT);
bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
u32 i2c_tran;

if (msg->flags & I2C_M_RD)
i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
else
- i2c_tran = i2c_count;
+ i2c_tran = i2c_dev->count;

/*
* If we did not get one ACK from slave when writing data, then we