From 399dee2371787825a1845de87c0cbee7b7c30ad6 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Mon, 28 Jul 2008 12:04:06 +0100 Subject: i2c: S3C2410: Pass the I2C bus number via drivers platform data Allow the platform data to specify the bus bumber that the new I2C bus will be given. This is to allow the use of the board registration mechanism to specify the new style of I2C device registration which allows boards to provide a list of attached devices. Note, as discussed on the mailing list, we have dropped backwards compatibility of adding an dynamic bus number as it should not affect most boards to have the bus pinned to 0 if they have either not specified platform data for driver. Any board supplying platform data will automatically have the bus_num field set to 0, and anyone who needs the driver on a different bus number can supply platform data to set bus_num. Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-s3c2410.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'drivers/i2c/busses/i2c-s3c2410.c') diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 007390ad9810..eef35d3f6073 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -752,9 +752,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) static int s3c24xx_i2c_probe(struct platform_device *pdev) { struct s3c24xx_i2c *i2c = &s3c24xx_i2c; + struct s3c2410_platform_i2c *pdata; struct resource *res; int ret; + pdata = s3c24xx_i2c_get_platformdata(&pdev->dev); + /* find the clock and enable it */ i2c->dev = &pdev->dev; @@ -832,7 +835,15 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res, (unsigned long)res->start); - ret = i2c_add_adapter(&i2c->adap); + /* Note, previous versions of the driver used i2c_add_adapter() + * to add the bus at any number. We now pass the bus number via + * the platform data, so if unset it will now default to always + * being bus 0. + */ + + i2c->adap.nr = pdata->bus_num; + + ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "failed to add bus to i2c core\n"); goto err_irq; -- cgit v1.2.3-59-g8ed1b From 61c7cff89224fc5651b5ba5ff2185d19304b2484 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Mon, 28 Jul 2008 12:04:07 +0100 Subject: i2c: S3C24XX I2C frequency scaling support. Add support for CPU frequency scaling to the S3C24XX I2C driver. Signed-off-by: Ben Dooks --- drivers/i2c/busses/i2c-s3c2410.c | 116 ++++++++++++++++++++++++++++++++++----- 1 file changed, 103 insertions(+), 13 deletions(-) (limited to 'drivers/i2c/busses/i2c-s3c2410.c') diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index eef35d3f6073..4864723c7425 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -64,6 +65,7 @@ struct s3c24xx_i2c { unsigned int tx_setup; enum s3c24xx_i2c_state state; + unsigned long clkrate; void __iomem *regs; struct clk *clk; @@ -71,6 +73,10 @@ struct s3c24xx_i2c { struct resource *irq; struct resource *ioarea; struct i2c_adapter adap; + +#ifdef CONFIG_CPU_FREQ + struct notifier_block freq_transition; +#endif }; /* default platform data to use if not supplied in the platform_device @@ -501,6 +507,9 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int unsigned long timeout; int ret; + if (!readl(i2c->regs + S3C2410_IICCON) & S3C2410_IICCON_IRQEN) + return -EIO; + ret = s3c24xx_i2c_set_master(i2c); if (ret != 0) { dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); @@ -636,27 +645,28 @@ static inline int freq_acceptable(unsigned int freq, unsigned int wanted) return (diff >= -2 && diff <= 2); } -/* s3c24xx_i2c_getdivisor +/* s3c24xx_i2c_clockrate * * work out a divisor for the user requested frequency setting, * either by the requested frequency, or scanning the acceptable * range of frequencies until something is found */ -static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c, - struct s3c2410_platform_i2c *pdata, - unsigned long *iicon, - unsigned int *got) +static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got) { + struct s3c2410_platform_i2c *pdata; unsigned long clkin = clk_get_rate(i2c->clk); - unsigned int divs, div1; + u32 iiccon; int freq; int start, end; + i2c->clkrate = clkin; + + pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent); clkin /= 1000; /* clkin now in KHz */ - dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n", + 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) { @@ -688,11 +698,79 @@ static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c, found: *got = freq; - *iicon |= (divs-1); - *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0; + + iiccon = readl(i2c->regs + S3C2410_IICCON); + iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512); + iiccon |= (divs-1); + + if (div1 == 512) + iiccon |= S3C2410_IICCON_TXDIV_512; + + writel(iiccon, i2c->regs + S3C2410_IICCON); + + return 0; +} + +#ifdef CONFIG_CPU_FREQ + +#define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition) + +static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct s3c24xx_i2c *i2c = freq_to_i2c(nb); + unsigned long flags; + unsigned int got; + int delta_f; + int ret; + + delta_f = clk_get_rate(i2c->clk) - i2c->clkrate; + + /* if we're post-change and the input clock has slowed down + * or at pre-change and the clock is about to speed up, then + * adjust our clock rate. <0 is slow, >0 speedup. + */ + + if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) || + (val == CPUFREQ_PRECHANGE && delta_f > 0)) { + spin_lock_irqsave(&i2c->lock, flags); + ret = s3c24xx_i2c_clockrate(i2c, &got); + spin_unlock_irqrestore(&i2c->lock, flags); + + if (ret < 0) + dev_err(i2c->dev, "cannot find frequency\n"); + else + dev_info(i2c->dev, "setting freq %d\n", got); + } + return 0; } +static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) +{ + i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition; + + return cpufreq_register_notifier(&i2c->freq_transition, + CPUFREQ_TRANSITION_NOTIFIER); +} + +static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) +{ + cpufreq_unregister_notifier(&i2c->freq_transition, + CPUFREQ_TRANSITION_NOTIFIER); +} + +#else +static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c) +{ + return 0; +} + +static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c) +{ +} +#endif + /* s3c24xx_i2c_init * * initialise the controller, set the IO lines and frequency @@ -719,9 +797,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr); + writel(iicon, i2c->regs + S3C2410_IICCON); + /* we need to work out the divisors for the clock... */ - if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) { + if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) { + writel(0, i2c->regs + S3C2410_IICCON); dev_err(i2c->dev, "cannot meet bus frequency required\n"); return -EINVAL; } @@ -730,8 +811,6 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c) dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq); dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon); - - writel(iicon, i2c->regs + S3C2410_IICCON); /* check for s3c2440 i2c controller */ @@ -835,6 +914,12 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res, (unsigned long)res->start); + ret = s3c24xx_i2c_register_cpufreq(i2c); + if (ret < 0) { + dev_err(&pdev->dev, "failed to register cpufreq notifier\n"); + goto err_irq; + } + /* Note, previous versions of the driver used i2c_add_adapter() * to add the bus at any number. We now pass the bus number via * the platform data, so if unset it will now default to always @@ -846,7 +931,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) ret = i2c_add_numbered_adapter(&i2c->adap); if (ret < 0) { dev_err(&pdev->dev, "failed to add bus to i2c core\n"); - goto err_irq; + goto err_cpufreq; } platform_set_drvdata(pdev, i2c); @@ -854,6 +939,9 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id); return 0; + err_cpufreq: + s3c24xx_i2c_deregister_cpufreq(i2c); + err_irq: free_irq(i2c->irq->start, i2c); @@ -881,6 +969,8 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev) { struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); + s3c24xx_i2c_deregister_cpufreq(i2c); + i2c_del_adapter(&i2c->adap); free_irq(i2c->irq->start, i2c); -- cgit v1.2.3-59-g8ed1b