diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-s3c2410.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-s3c2410.c | 77 |
1 files changed, 31 insertions, 46 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 5b7f95641ba4..1691ef0f1ee1 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"); |