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i2c: mxs: Abstract out the MXS I2C speed setup

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This patch pulls out the I2C speed setup from the i2c_init() call
and implements the bus configuration lookup table with register
values that needs to be programmed into the I2C IP to run at
particular speed.

This patch is a first step towards implementing run-time I2C bus
speed configuration for the MXS I2C IP.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
This commit is contained in:
Marek Vasut 2012-11-12 14:34:28 +00:00 • committed by Tom Rini
parent 06afa388b2
commit f32a470ed3
1 changed files with 37 additions and 20 deletions
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57
drivers/i2c/mxs_i2c.c
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@ -210,34 +210,51 @@ int i2c_probe(uchar chip)
return ret;
}
static struct mxs_i2c_speed_table {
uint32_t speed;
uint32_t timing0;
uint32_t timing1;
} mxs_i2c_tbl[] = {
{
100000,
(0x0078 << I2C_TIMING0_HIGH_COUNT_OFFSET) |
(0x0030 << I2C_TIMING0_RCV_COUNT_OFFSET),
(0x0080 << I2C_TIMING1_LOW_COUNT_OFFSET) |
(0x0030 << I2C_TIMING1_XMIT_COUNT_OFFSET)
},
{
400000,
(0x000f << I2C_TIMING0_HIGH_COUNT_OFFSET) |
(0x0007 << I2C_TIMING0_RCV_COUNT_OFFSET),
(0x001f << I2C_TIMING1_LOW_COUNT_OFFSET) |
(0x000f << I2C_TIMING1_XMIT_COUNT_OFFSET),
}
};
static struct mxs_i2c_speed_table *mxs_i2c_speed_to_cfg(uint32_t speed)
{
int i;
for (i = 0; i < ARRAY_SIZE(mxs_i2c_tbl); i++)
if (mxs_i2c_tbl[i].speed == speed)
return &mxs_i2c_tbl[i];
return NULL;
}
void i2c_init(int speed, int slaveadd)
{
struct mxs_i2c_regs *i2c_regs = (struct mxs_i2c_regs *)MXS_I2C0_BASE;
struct mxs_i2c_speed_table *spd = mxs_i2c_speed_to_cfg(speed);
mxs_i2c_reset();
switch (speed) {
case 100000:
writel((0x0078 << I2C_TIMING0_HIGH_COUNT_OFFSET) |
(0x0030 << I2C_TIMING0_RCV_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing0);
writel((0x0080 << I2C_TIMING1_LOW_COUNT_OFFSET) |
(0x0030 << I2C_TIMING1_XMIT_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing1);
break;
case 400000:
writel((0x000f << I2C_TIMING0_HIGH_COUNT_OFFSET) |
(0x0007 << I2C_TIMING0_RCV_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing0);
writel((0x001f << I2C_TIMING1_LOW_COUNT_OFFSET) |
(0x000f << I2C_TIMING1_XMIT_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing1);
break;
default:
if (!spd) {
printf("MXS I2C: Invalid speed selected (%d Hz)\n", speed);
return;
}
mxs_i2c_reset();
writel(spd->timing0, &i2c_regs->hw_i2c_timing0);
writel(spd->timing1, &i2c_regs->hw_i2c_timing1);
writel((0x0015 << I2C_TIMING2_BUS_FREE_OFFSET) |
(0x000d << I2C_TIMING2_LEADIN_COUNT_OFFSET),
&i2c_regs->hw_i2c_timing2);