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Diffstat (limited to 'drivers/i2c/busses/i2c-s3c2410.c')
-rw-r--r--drivers/i2c/busses/i2c-s3c2410.c129
1 files changed, 115 insertions, 14 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 007390ad9810..4864723c7425 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -33,6 +33,7 @@
33#include <linux/err.h> 33#include <linux/err.h>
34#include <linux/platform_device.h> 34#include <linux/platform_device.h>
35#include <linux/clk.h> 35#include <linux/clk.h>
36#include <linux/cpufreq.h>
36 37
37#include <asm/hardware.h> 38#include <asm/hardware.h>
38#include <asm/irq.h> 39#include <asm/irq.h>
@@ -64,6 +65,7 @@ struct s3c24xx_i2c {
64 unsigned int tx_setup; 65 unsigned int tx_setup;
65 66
66 enum s3c24xx_i2c_state state; 67 enum s3c24xx_i2c_state state;
68 unsigned long clkrate;
67 69
68 void __iomem *regs; 70 void __iomem *regs;
69 struct clk *clk; 71 struct clk *clk;
@@ -71,6 +73,10 @@ struct s3c24xx_i2c {
71 struct resource *irq; 73 struct resource *irq;
72 struct resource *ioarea; 74 struct resource *ioarea;
73 struct i2c_adapter adap; 75 struct i2c_adapter adap;
76
77#ifdef CONFIG_CPU_FREQ
78 struct notifier_block freq_transition;
79#endif
74}; 80};
75 81
76/* default platform data to use if not supplied in the platform_device 82/* 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
501 unsigned long timeout; 507 unsigned long timeout;
502 int ret; 508 int ret;
503 509
510 if (!readl(i2c->regs + S3C2410_IICCON) & S3C2410_IICCON_IRQEN)
511 return -EIO;
512
504 ret = s3c24xx_i2c_set_master(i2c); 513 ret = s3c24xx_i2c_set_master(i2c);
505 if (ret != 0) { 514 if (ret != 0) {
506 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret); 515 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)
636 return (diff >= -2 && diff <= 2); 645 return (diff >= -2 && diff <= 2);
637} 646}
638 647
639/* s3c24xx_i2c_getdivisor 648/* s3c24xx_i2c_clockrate
640 * 649 *
641 * work out a divisor for the user requested frequency setting, 650 * work out a divisor for the user requested frequency setting,
642 * either by the requested frequency, or scanning the acceptable 651 * either by the requested frequency, or scanning the acceptable
643 * range of frequencies until something is found 652 * range of frequencies until something is found
644*/ 653*/
645 654
646static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c, 655static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
647 struct s3c2410_platform_i2c *pdata,
648 unsigned long *iicon,
649 unsigned int *got)
650{ 656{
657 struct s3c2410_platform_i2c *pdata;
651 unsigned long clkin = clk_get_rate(i2c->clk); 658 unsigned long clkin = clk_get_rate(i2c->clk);
652
653 unsigned int divs, div1; 659 unsigned int divs, div1;
660 u32 iiccon;
654 int freq; 661 int freq;
655 int start, end; 662 int start, end;
656 663
664 i2c->clkrate = clkin;
665
666 pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
657 clkin /= 1000; /* clkin now in KHz */ 667 clkin /= 1000; /* clkin now in KHz */
658 668
659 dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n", 669 dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n",
660 pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq); 670 pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
661 671
662 if (pdata->bus_freq != 0) { 672 if (pdata->bus_freq != 0) {
@@ -688,11 +698,79 @@ static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
688 698
689 found: 699 found:
690 *got = freq; 700 *got = freq;
691 *iicon |= (divs-1); 701
692 *iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0; 702 iiccon = readl(i2c->regs + S3C2410_IICCON);
703 iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
704 iiccon |= (divs-1);
705
706 if (div1 == 512)
707 iiccon |= S3C2410_IICCON_TXDIV_512;
708
709 writel(iiccon, i2c->regs + S3C2410_IICCON);
710
711 return 0;
712}
713
714#ifdef CONFIG_CPU_FREQ
715
716#define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
717
718static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
719 unsigned long val, void *data)
720{
721 struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
722 unsigned long flags;
723 unsigned int got;
724 int delta_f;
725 int ret;
726
727 delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
728
729 /* if we're post-change and the input clock has slowed down
730 * or at pre-change and the clock is about to speed up, then
731 * adjust our clock rate. <0 is slow, >0 speedup.
732 */
733
734 if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
735 (val == CPUFREQ_PRECHANGE && delta_f > 0)) {
736 spin_lock_irqsave(&i2c->lock, flags);
737 ret = s3c24xx_i2c_clockrate(i2c, &got);
738 spin_unlock_irqrestore(&i2c->lock, flags);
739
740 if (ret < 0)
741 dev_err(i2c->dev, "cannot find frequency\n");
742 else
743 dev_info(i2c->dev, "setting freq %d\n", got);
744 }
745
746 return 0;
747}
748
749static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
750{
751 i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
752
753 return cpufreq_register_notifier(&i2c->freq_transition,
754 CPUFREQ_TRANSITION_NOTIFIER);
755}
756
757static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
758{
759 cpufreq_unregister_notifier(&i2c->freq_transition,
760 CPUFREQ_TRANSITION_NOTIFIER);
761}
762
763#else
764static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
765{
693 return 0; 766 return 0;
694} 767}
695 768
769static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
770{
771}
772#endif
773
696/* s3c24xx_i2c_init 774/* s3c24xx_i2c_init
697 * 775 *
698 * initialise the controller, set the IO lines and frequency 776 * initialise the controller, set the IO lines and frequency
@@ -719,9 +797,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
719 797
720 dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr); 798 dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
721 799
800 writel(iicon, i2c->regs + S3C2410_IICCON);
801
722 /* we need to work out the divisors for the clock... */ 802 /* we need to work out the divisors for the clock... */
723 803
724 if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) { 804 if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
805 writel(0, i2c->regs + S3C2410_IICCON);
725 dev_err(i2c->dev, "cannot meet bus frequency required\n"); 806 dev_err(i2c->dev, "cannot meet bus frequency required\n");
726 return -EINVAL; 807 return -EINVAL;
727 } 808 }
@@ -730,8 +811,6 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
730 811
731 dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq); 812 dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
732 dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon); 813 dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
733
734 writel(iicon, i2c->regs + S3C2410_IICCON);
735 814
736 /* check for s3c2440 i2c controller */ 815 /* check for s3c2440 i2c controller */
737 816
@@ -752,9 +831,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
752static int s3c24xx_i2c_probe(struct platform_device *pdev) 831static int s3c24xx_i2c_probe(struct platform_device *pdev)
753{ 832{
754 struct s3c24xx_i2c *i2c = &s3c24xx_i2c; 833 struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
834 struct s3c2410_platform_i2c *pdata;
755 struct resource *res; 835 struct resource *res;
756 int ret; 836 int ret;
757 837
838 pdata = s3c24xx_i2c_get_platformdata(&pdev->dev);
839
758 /* find the clock and enable it */ 840 /* find the clock and enable it */
759 841
760 i2c->dev = &pdev->dev; 842 i2c->dev = &pdev->dev;
@@ -832,17 +914,34 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
832 dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res, 914 dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res,
833 (unsigned long)res->start); 915 (unsigned long)res->start);
834 916
835 ret = i2c_add_adapter(&i2c->adap); 917 ret = s3c24xx_i2c_register_cpufreq(i2c);
836 if (ret < 0) { 918 if (ret < 0) {
837 dev_err(&pdev->dev, "failed to add bus to i2c core\n"); 919 dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
838 goto err_irq; 920 goto err_irq;
839 } 921 }
840 922
923 /* Note, previous versions of the driver used i2c_add_adapter()
924 * to add the bus at any number. We now pass the bus number via
925 * the platform data, so if unset it will now default to always
926 * being bus 0.
927 */
928
929 i2c->adap.nr = pdata->bus_num;
930
931 ret = i2c_add_numbered_adapter(&i2c->adap);
932 if (ret < 0) {
933 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
934 goto err_cpufreq;
935 }
936
841 platform_set_drvdata(pdev, i2c); 937 platform_set_drvdata(pdev, i2c);
842 938
843 dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id); 939 dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
844 return 0; 940 return 0;
845 941
942 err_cpufreq:
943 s3c24xx_i2c_deregister_cpufreq(i2c);
944
846 err_irq: 945 err_irq:
847 free_irq(i2c->irq->start, i2c); 946 free_irq(i2c->irq->start, i2c);
848 947
@@ -870,6 +969,8 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
870{ 969{
871 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev); 970 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
872 971
972 s3c24xx_i2c_deregister_cpufreq(i2c);
973
873 i2c_del_adapter(&i2c->adap); 974 i2c_del_adapter(&i2c->adap);
874 free_irq(i2c->irq->start, i2c); 975 free_irq(i2c->irq->start, i2c);
875 976