dw_i2c_enable() is used to dis-/en-able the I2C controller. It makes sense to add such a function, as the controller is dis-/en-abled multiple times in the code. Additionally, this function now checks, if the controller is really dis-/en-abled. This code is copied from the Linux I2C driver version.
Signed-off-by: Stefan Roese sr@denx.de Cc: Simon Glass sjg@chromium.org Cc: Bin Meng bmeng.cn@gmail.com Cc: Marek Vasut marex@denx.de Cc: Heiko Schocher hs@denx.de --- drivers/i2c/designware_i2c.c | 46 +++++++++++++++++++++++++------------------- 1 file changed, 26 insertions(+), 20 deletions(-)
diff --git a/drivers/i2c/designware_i2c.c b/drivers/i2c/designware_i2c.c index e768cde..c8ea520 100644 --- a/drivers/i2c/designware_i2c.c +++ b/drivers/i2c/designware_i2c.c @@ -34,6 +34,26 @@ static struct i2c_regs *i2c_get_base(struct i2c_adapter *adap) return NULL; }
+static void dw_i2c_enable(struct i2c_regs *i2c_base, bool enable) +{ + int timeout = 100; + + do { + writel(enable, &i2c_base->ic_enable); + if ((readl(&i2c_base->ic_enable_status) & 1) == enable) + return; + + /* + * Wait 10 times the signaling period of the highest I2C + * transfer supported by the driver (for 400KHz this is + * 25us) as described in the DesignWare I2C databook. + */ + udelay(25); + } while (timeout--); + + printf("timeout in %sabling I2C adapter\n", enable ? "en" : "dis"); +} + /* * set_speed - Set the i2c speed mode (standard, high, fast) * @i2c_spd: required i2c speed mode @@ -45,12 +65,9 @@ static void set_speed(struct i2c_adapter *adap, int i2c_spd) struct i2c_regs *i2c_base = i2c_get_base(adap); unsigned int cntl; unsigned int hcnt, lcnt; - unsigned int enbl;
/* to set speed cltr must be disabled */ - enbl = readl(&i2c_base->ic_enable); - enbl &= ~IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 0);
cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));
@@ -84,8 +101,7 @@ static void set_speed(struct i2c_adapter *adap, int i2c_spd) writel(cntl, &i2c_base->ic_con);
/* Enable back i2c now speed set */ - enbl |= IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 1); }
/* @@ -123,12 +139,9 @@ static void dw_i2c_init(struct i2c_adapter *adap, int speed, int slaveaddr) { struct i2c_regs *i2c_base = i2c_get_base(adap); - unsigned int enbl;
/* Disable i2c */ - enbl = readl(&i2c_base->ic_enable); - enbl &= ~IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 0);
writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_base->ic_con); writel(IC_RX_TL, &i2c_base->ic_rx_tl); @@ -138,9 +151,7 @@ static void dw_i2c_init(struct i2c_adapter *adap, int speed, writel(slaveaddr, &i2c_base->ic_sar);
/* Enable i2c */ - enbl = readl(&i2c_base->ic_enable); - enbl |= IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 1); }
/* @@ -152,19 +163,14 @@ static void dw_i2c_init(struct i2c_adapter *adap, int speed, static void i2c_setaddress(struct i2c_adapter *adap, unsigned int i2c_addr) { struct i2c_regs *i2c_base = i2c_get_base(adap); - unsigned int enbl;
/* Disable i2c */ - enbl = readl(&i2c_base->ic_enable); - enbl &= ~IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 0);
writel(i2c_addr, &i2c_base->ic_tar);
/* Enable i2c */ - enbl = readl(&i2c_base->ic_enable); - enbl |= IC_ENABLE_0B; - writel(enbl, &i2c_base->ic_enable); + dw_i2c_enable(i2c_base, 1); }
/*