From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Mon, 22 Jul 2013 22:56:44 +0200 Subject: [PATCH v4 02/20] clocksource: samsung_pwm_timer: Correct definition of AUTORELOAD bit In-Reply-To: <9612221.r4mx9bHE64@flatron> References: <1374278673-25615-1-git-send-email-tomasz.figa@gmail.com> <1374278673-25615-4-git-send-email-tomasz.figa@gmail.com> <51ECABF1.4040600@linaro.org> <9612221.r4mx9bHE64@flatron> Message-ID: <51ED9C8C.10803@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 07/22/2013 09:43 AM, Tomasz Figa wrote: > On Monday 22 of July 2013 05:50:09 Daniel Lezcano wrote: >> On 07/20/2013 02:04 AM, Tomasz Figa wrote: >>> PWM channel 4 has its autoreload bit located at different position. >>> This patch fixes the driver to account for that. >>> >>> This fixes a problem with the clocksource hanging after it overflows >>> because it is not reloaded any more. >>> >>> Signed-off-by: Tomasz Figa >>> --- >>> >>> drivers/clocksource/samsung_pwm_timer.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/clocksource/samsung_pwm_timer.c >>> b/drivers/clocksource/samsung_pwm_timer.c index 3fa5b07..e238fb0 >>> 100644 >>> --- a/drivers/clocksource/samsung_pwm_timer.c >>> +++ b/drivers/clocksource/samsung_pwm_timer.c >>> @@ -47,7 +47,8 @@ >>> >>> #define TCON_START(chan) (1 << (4 * (chan) + 0)) >>> #define TCON_MANUALUPDATE(chan) (1 << (4 * (chan) + 1)) >>> #define TCON_INVERT(chan) (1 << (4 * (chan) + 2)) >>> >>> -#define TCON_AUTORELOAD(chan) (1 << (4 * (chan) + 3)) >>> +#define TCON_AUTORELOAD(chan) (1 << (4 * (chan) \ >>> + + (((chan) < 5) ? 3 : 2))) >> >> This macro is not readable. Please, fix it up with a comment please. > > /* > * Channel 4 (logically 5 in TCON register) has different position > * of autoreload bit. > */ > #define _TCON_AUTORELOAD(chan) (1 << (4 * (chan) + 3)) > #define _TCON_AUTORELOAD4(chan) (1 << (4 * (chan) + 2)) > #define TCON_AUTORELOAD(chan) ((chan < 5) ? > _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan)) > > What do you think? I don't get the arithmetic here and the code is poor in comment. A nice comment would valuable here. May be you can replace 1 << bla by BIT(bla) ? -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog