Patchwork [v3] i2c: s3c2410: dont need CPU_FREQ transitions for exynos series

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Submitter Naveen Krishna Ch
Date Nov. 19, 2013, 6:18 a.m.
Message ID <1384841915-8264-1-git-send-email-ch.naveen@samsung.com>
Download mbox | patch
Permalink /patch/292291/
State Superseded
Headers show

Comments

Naveen Krishna Ch - Nov. 19, 2013, 6:18 a.m.
For Exynos4 and Exynos5 SoCs from Samsung the i2c clock is based
on a fixed 66 MHz peripheral clock, and therefore is completely
independent of the cpu frequency.
Thus, registering for a CPU freq notifier is very wasteful.

This patch modifes the code such that, i2c bus registers to
cpu_freq_transition only if CONFIG_CPU_FREQ_S3C24XX is enabled.

This change should save a bunch of cpufreq transitions calls
which does not apply to exynos SoCs.

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
---
Changes since v2:
None, Rebased on for-next of linux-i2c git repo.

Changes since v1:
Use CONFIG_CPU_FREQ_S3C24XX instead of (CONFIG_CPU_FREQ & !CONFIG_EXYNOS)
As commented by Tomasz

 drivers/i2c/busses/i2c-s3c2410.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
Doug Anderson - Nov. 25, 2013, 11:41 p.m.
Naveen,

On Mon, Nov 18, 2013 at 10:18 PM, Naveen Krishna Chatradhi
<ch.naveen@samsung.com> wrote:
> For Exynos4 and Exynos5 SoCs from Samsung the i2c clock is based
> on a fixed 66 MHz peripheral clock, and therefore is completely
> independent of the cpu frequency.
> Thus, registering for a CPU freq notifier is very wasteful.
>
> This patch modifes the code such that, i2c bus registers to
> cpu_freq_transition only if CONFIG_CPU_FREQ_S3C24XX is enabled.
>
> This change should save a bunch of cpufreq transitions calls
> which does not apply to exynos SoCs.
>
> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
> Reviewed-by: Doug Anderson <dianders@chromium.org>
> ---
> Changes since v2:
> None, Rebased on for-next of linux-i2c git repo.
>
> Changes since v1:
> Use CONFIG_CPU_FREQ_S3C24XX instead of (CONFIG_CPU_FREQ & !CONFIG_EXYNOS)
> As commented by Tomasz
>
>  drivers/i2c/busses/i2c-s3c2410.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Can you please spin this with comments from
<https://patchwork.kernel.org/patch/3235091/>?  Thanks!

-Doug
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naveen krishna chatradhi - Nov. 26, 2013, 4:07 a.m.
Hello Doug,

On 26 November 2013 05:11, Doug Anderson <dianders@chromium.org> wrote:
> Naveen,
>
> On Mon, Nov 18, 2013 at 10:18 PM, Naveen Krishna Chatradhi
> <ch.naveen@samsung.com> wrote:
>> For Exynos4 and Exynos5 SoCs from Samsung the i2c clock is based
>> on a fixed 66 MHz peripheral clock, and therefore is completely
>> independent of the cpu frequency.
>> Thus, registering for a CPU freq notifier is very wasteful.
>>
>> This patch modifes the code such that, i2c bus registers to
>> cpu_freq_transition only if CONFIG_CPU_FREQ_S3C24XX is enabled.
>>
>> This change should save a bunch of cpufreq transitions calls
>> which does not apply to exynos SoCs.
>>
>> Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
>> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
>> Reviewed-by: Doug Anderson <dianders@chromium.org>
>> ---
>> Changes since v2:
>> None, Rebased on for-next of linux-i2c git repo.
>>
>> Changes since v1:
>> Use CONFIG_CPU_FREQ_S3C24XX instead of (CONFIG_CPU_FREQ & !CONFIG_EXYNOS)
>> As commented by Tomasz
>>
>>  drivers/i2c/busses/i2c-s3c2410.c |    4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> Can you please spin this with comments from
> <https://patchwork.kernel.org/patch/3235091/>?  Thanks!
Thanks for pointing out for me

To summarize, Post f023f8dd59 commit we should be using
ARM_S3C24XX_CPUFREQ instead of ARM_S3C24XX_CPUFREQ right.

Will re-spin with this changes.
>
> -Doug
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Patch

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index bf8fb94..fa51dff 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -123,7 +123,7 @@  struct s3c24xx_i2c {
 	struct s3c2410_platform_i2c	*pdata;
 	int			gpios[2];
 	struct pinctrl          *pctrl;
-#ifdef CONFIG_CPU_FREQ
+#if defined(CONFIG_CPU_FREQ_S3C24XX)
 	struct notifier_block	freq_transition;
 #endif
 };
@@ -843,7 +843,7 @@  static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 	return 0;
 }
 
-#ifdef CONFIG_CPU_FREQ
+#if defined(CONFIG_CPU_FREQ_S3C24XX)
 
 #define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)