| Message ID | 1381818232-12542-1-git-send-email-ch.naveen@samsung.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, Oct 15, 2013 at 3:23 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> > --- > 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(-) > > diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c > index cab1c91..97f14f7 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) > > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, On Mon, Oct 14, 2013 at 11:56 PM, Kyungmin Park <kmpark@infradead.org> wrote: > On Tue, Oct 15, 2013 at 3:23 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> >> --- >> 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(-) Looks great to me. Thank you for the suggestions Tomasz, as always. Reviewed-by: Doug Anderson <dianders@chromium.org> We need to come up with a solution for the CPU_FREQ stuff in s3c2410_wdt too. We could use a similar solution but since the CPU_FREQ stuff in s3c2410_wdt is more than just an optimization it means that it's not good if S3C24XX is included in a multiplatform kernel. (For the watchdog it's more than just an optimization since every frequency transition actually pets the watchdog, making it useless when you transition several times per second). -Doug -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index cab1c91..97f14f7 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)
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> --- 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(-)