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path: root/drivers/i2c/busses/i2c-s3c2410.c
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Diffstat (limited to 'drivers/i2c/busses/i2c-s3c2410.c')
-rw-r--r--drivers/i2c/busses/i2c-s3c2410.c77
1 files changed, 31 insertions, 46 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 5b7f95641ba..1691ef0f1ee 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -1,6 +1,6 @@
/* linux/drivers/i2c/busses/i2c-s3c2410.c
*
- * Copyright (C) 2004,2005 Simtec Electronics
+ * Copyright (C) 2004,2005,2009 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>
*
* S3C2410 I2C Controller
@@ -590,18 +590,6 @@ static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
return clkin / (calc_divs * calc_div1);
}
-/* freq_acceptable
- *
- * test wether a frequency is within the acceptable range of error
-*/
-
-static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
-{
- int diff = freq - wanted;
-
- return diff >= -2 && diff <= 2;
-}
-
/* s3c24xx_i2c_clockrate
*
* work out a divisor for the user requested frequency setting,
@@ -614,44 +602,28 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
struct s3c2410_platform_i2c *pdata = i2c->dev->platform_data;
unsigned long clkin = clk_get_rate(i2c->clk);
unsigned int divs, div1;
+ unsigned long target_frequency;
u32 iiccon;
int freq;
- int start, end;
i2c->clkrate = clkin;
clkin /= 1000; /* clkin now in KHz */
- dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n",
- pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
-
- if (pdata->bus_freq != 0) {
- freq = s3c24xx_i2c_calcdivisor(clkin, pdata->bus_freq/1000,
- &div1, &divs);
- if (freq_acceptable(freq, pdata->bus_freq/1000))
- goto found;
- }
-
- /* ok, we may have to search for something suitable... */
+ dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
- start = (pdata->max_freq == 0) ? pdata->bus_freq : pdata->max_freq;
- end = pdata->min_freq;
+ target_frequency = pdata->frequency ? pdata->frequency : 100000;
- start /= 1000;
- end /= 1000;
+ target_frequency /= 1000; /* Target frequency now in KHz */
- /* search loop... */
+ freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
- for (; start > end; start--) {
- freq = s3c24xx_i2c_calcdivisor(clkin, start, &div1, &divs);
- if (freq_acceptable(freq, start))
- goto found;
+ if (freq > target_frequency) {
+ dev_err(i2c->dev,
+ "Unable to achieve desired frequency %luKHz." \
+ " Lowest achievable %dKHz\n", target_frequency, freq);
+ return -EINVAL;
}
- /* cannot find frequency spec */
-
- return -EINVAL;
-
- found:
*got = freq;
iiccon = readl(i2c->regs + S3C2410_IICCON);
@@ -663,6 +635,23 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
writel(iiccon, i2c->regs + S3C2410_IICCON);
+ if (s3c24xx_i2c_is2440(i2c)) {
+ unsigned long sda_delay;
+
+ if (pdata->sda_delay) {
+ sda_delay = (freq / 1000) * pdata->sda_delay;
+ sda_delay /= 1000000;
+ sda_delay = DIV_ROUND_UP(sda_delay, 5);
+ if (sda_delay > 3)
+ sda_delay = 3;
+ sda_delay |= S3C2410_IICLC_FILTER_ON;
+ } else
+ sda_delay = 0;
+
+ dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
+ writel(sda_delay, i2c->regs + S3C2440_IICLC);
+ }
+
return 0;
}
@@ -769,11 +758,8 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
/* check for s3c2440 i2c controller */
- if (s3c24xx_i2c_is2440(i2c)) {
- dev_dbg(i2c->dev, "S3C2440_IICLC=%08x\n", pdata->sda_delay);
-
- writel(pdata->sda_delay, i2c->regs + S3C2440_IICLC);
- }
+ if (s3c24xx_i2c_is2440(i2c))
+ writel(0x0, i2c->regs + S3C2440_IICLC);
return 0;
}
@@ -1018,14 +1004,13 @@ static int __init i2c_adap_s3c_init(void)
return ret;
}
+subsys_initcall(i2c_adap_s3c_init);
static void __exit i2c_adap_s3c_exit(void)
{
platform_driver_unregister(&s3c2410_i2c_driver);
platform_driver_unregister(&s3c2440_i2c_driver);
}
-
-module_init(i2c_adap_s3c_init);
module_exit(i2c_adap_s3c_exit);
MODULE_DESCRIPTION("S3C24XX I2C Bus driver");