i2c: sirf: reset i2c controller early after we get a noack
Due to hardware ANOMALY, we need to reset I2C earlier after
we get NOACK while accessing non-existing clients, otherwise
we will get errors even we access existing clients later
Signed-off-by: Zhiwu Song <Zhiwu.Song@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
index 0ff22e2..ff47a76 100644
--- a/drivers/i2c/busses/i2c-sirf.c
+++ b/drivers/i2c/busses/i2c-sirf.c
@@ -64,6 +64,8 @@
#define SIRFSOC_I2C_START BIT(7)
#define SIRFSOC_I2C_DEFAULT_SPEED 100000
+#define SIRFSOC_I2C_ERR_NOACK 1
+#define SIRFSOC_I2C_ERR_TIMEOUT 2
struct sirfsoc_i2c {
void __iomem *base;
@@ -142,14 +144,24 @@
if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {
/* Error conditions */
- siic->err_status = 1;
+ siic->err_status = SIRFSOC_I2C_ERR_NOACK;
writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);
if (i2c_stat & SIRFSOC_I2C_STAT_NACK)
- dev_err(&siic->adapter.dev, "ACK not received\n");
+ dev_dbg(&siic->adapter.dev, "ACK not received\n");
else
dev_err(&siic->adapter.dev, "I2C error\n");
+ /*
+ * Due to hardware ANOMALY, we need to reset I2C earlier after
+ * we get NOACK while accessing non-existing clients, otherwise
+ * we will get errors even we access existing clients later
+ */
+ writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
+ siic->base + SIRFSOC_I2C_CTRL);
+ while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
+ cpu_relax();
+
complete(&siic->done);
} else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {
/* CMD buffer execution complete */
@@ -190,7 +202,6 @@
u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);
/* timeout waiting for the xfer to finish or fail */
int timeout = msecs_to_jiffies((msg->len + 1) * 50);
- int ret = 0;
i2c_sirfsoc_set_address(siic, msg);
@@ -199,7 +210,7 @@
i2c_sirfsoc_queue_cmd(siic);
if (wait_for_completion_timeout(&siic->done, timeout) == 0) {
- siic->err_status = 1;
+ siic->err_status = SIRFSOC_I2C_ERR_TIMEOUT;
dev_err(&siic->adapter.dev, "Transfer timeout\n");
}
@@ -207,16 +218,14 @@
siic->base + SIRFSOC_I2C_CTRL);
writel(0, siic->base + SIRFSOC_I2C_CMD_START);
- if (siic->err_status) {
+ /* i2c control doesn't response, reset it */
+ if (siic->err_status == SIRFSOC_I2C_ERR_TIMEOUT) {
writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
siic->base + SIRFSOC_I2C_CTRL);
while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
cpu_relax();
-
- ret = -EIO;
}
-
- return ret;
+ return siic->err_status ? -EIO : 0;
}
static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)