designware_i2c: disable i2c controller during target address setup

As it is stated in DesignWare I2C databook: writes to IC_TAR (0x4)
register succeed only when IC_ENABLE[0] is set to 0.

Signed-off-by: Alexey Brodkin <[email protected]>
Cc: Tom Rini <[email protected]>
cc: Armando Visconti <[email protected]>
Cc: Stefan Roese <[email protected]>
Cc: Albert ARIBAUD <[email protected]>
Cc: Heiko Schocher <[email protected]>
Cc: Vipin KUMAR <[email protected]>
Cc: Tom Rix <[email protected]>
Cc: Mischa Jonker <[email protected]>

diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c
index c2f06627d3e312b52a24c6310927a317d4dd506d..c5c6015e99555c80621856428eee863388bb0c8e 100644 (file)
--- a/drivers/i2c/designware_i2c.c
+++ b/drivers/i2c/designware_i2c.c
@@ -151,7 +151,19 @@ void i2c_init(int speed, int slaveadd)
  */
 static void i2c_setaddress(unsigned int i2c_addr)
 {
+       unsigned int enbl;
+
+       /* Disable i2c */
+       enbl = readl(&i2c_regs_p->ic_enable);
+       enbl &= ~IC_ENABLE_0B;
+       writel(enbl, &i2c_regs_p->ic_enable);
+
        writel(i2c_addr, &i2c_regs_p->ic_tar);
+
+       /* Enable i2c */
+       enbl = readl(&i2c_regs_p->ic_enable);
+       enbl |= IC_ENABLE_0B;
+       writel(enbl, &i2c_regs_p->ic_enable);
 }
 
 /*