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i2c: designware_i2c: Add dw_i2c_enable() helper function

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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>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Stefan Roese 2016-04-21 08:19:38 +02:00 committed by Heiko Schocher
parent e209828cbd
commit 1c8b089b45
1 changed files with 27 additions and 20 deletions
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47
drivers/i2c/designware_i2c.c
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@ -34,6 +34,27 @@ 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)
{
u32 ena = enable ? IC_ENABLE_0B : 0;
int timeout = 100;
do {
writel(ena, &i2c_base->ic_enable);
if ((readl(&i2c_base->ic_enable_status) & IC_ENABLE_0B) == ena)
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 +66,9 @@ 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, false);
cntl = (readl(&i2c_base->ic_con) & (~IC_CON_SPD_MSK));
@ -84,8 +102,7 @@ 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, true);
}
/*
@ -123,12 +140,9 @@ 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, false);
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 +152,7 @@ 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, true);
}
/*
@ -152,19 +164,14 @@ 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, false);
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, true);
}
/*