[U-Boot] [PATCH 1/2] mxs: i2c: Restore speed setting after block reset

Marek Vasut marex at denx.de
Sat Dec 1 05:17:06 CET 2012


The I2C block reset configures the I2C bus speed to strange value.
Read the I2C speed from the block before reseting the block and
restore it afterwards, so the I2C operates correctly. This issue
can be replicated by doing unsuccessful I2C transfer, after such
transfer finishes, the I2C block clock speed is misconfigured.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Heiko Schocher <hs at denx.de>
Cc: Fabio Estevam <fabio.estevam at freescale.com>
---
 drivers/i2c/mxs_i2c.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/mxs_i2c.c b/drivers/i2c/mxs_i2c.c
index 006fb91..73a6659 100644
--- a/drivers/i2c/mxs_i2c.c
+++ b/drivers/i2c/mxs_i2c.c
@@ -40,6 +40,7 @@ void mxs_i2c_reset(void)
 {
 	struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
 	int ret;
+	int speed = i2c_get_bus_speed();
 
 	ret = mxs_reset_block(&i2c_regs->hw_i2c_ctrl0_reg);
 	if (ret) {
@@ -53,6 +54,8 @@ void mxs_i2c_reset(void)
 		&i2c_regs->hw_i2c_ctrl1_clr);
 
 	writel(I2C_QUEUECTRL_PIO_QUEUE_MODE, &i2c_regs->hw_i2c_queuectrl_set);
+
+	i2c_set_bus_speed(speed);
 }
 
 void mxs_i2c_setup_read(uint8_t chip, int len)
-- 
1.7.10.4



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