* [PATCH] rtc: omap: use rtc_write to access OMAP_RTC_OSC_REG
@ 2021-04-25 14:59 Dario Binacchi
2021-04-29 21:29 ` Alexandre Belloni
0 siblings, 1 reply; 2+ messages in thread
From: Dario Binacchi @ 2021-04-25 14:59 UTC (permalink / raw)
To: linux-kernel
Cc: Dario Binacchi, Alessandro Zummo, Alexandre Belloni, linux-rtc
The RTC_OSC_REG register is 32-bit, but the useful information is found
in the 7 least significant bits (bits 7-31 are reserved). And in fact,
as you can see from the code, all read accesses are 8-bit, as well as
some writes. Let's make sure all writes are 8-bit. Moreover, in contexts
where consecutive reads / writes after the busy check must take place
within 15 us, it is better not to waste time on useless accesses.
Signed-off-by: Dario Binacchi <dariobin@libero.it>
---
drivers/rtc/rtc-omap.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
index dc7db2477f88..d46e0f0cc502 100644
--- a/drivers/rtc/rtc-omap.c
+++ b/drivers/rtc/rtc-omap.c
@@ -786,8 +786,7 @@ static int omap_rtc_probe(struct platform_device *pdev)
/* enable RTC functional clock */
if (rtc->type->has_32kclk_en) {
reg = rtc_read(rtc, OMAP_RTC_OSC_REG);
- rtc_writel(rtc, OMAP_RTC_OSC_REG,
- reg | OMAP_RTC_OSC_32KCLK_EN);
+ rtc_write(rtc, OMAP_RTC_OSC_REG, reg | OMAP_RTC_OSC_32KCLK_EN);
}
/* clear old status */
@@ -845,7 +844,7 @@ static int omap_rtc_probe(struct platform_device *pdev)
reg = rtc_read(rtc, OMAP_RTC_OSC_REG);
reg &= ~OMAP_RTC_OSC_OSC32K_GZ_DISABLE;
reg |= OMAP_RTC_OSC_32KCLK_EN | OMAP_RTC_OSC_SEL_32KCLK_SRC;
- rtc_writel(rtc, OMAP_RTC_OSC_REG, reg);
+ rtc_write(rtc, OMAP_RTC_OSC_REG, reg);
}
rtc->type->lock(rtc);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] rtc: omap: use rtc_write to access OMAP_RTC_OSC_REG
2021-04-25 14:59 [PATCH] rtc: omap: use rtc_write to access OMAP_RTC_OSC_REG Dario Binacchi
@ 2021-04-29 21:29 ` Alexandre Belloni
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre Belloni @ 2021-04-29 21:29 UTC (permalink / raw)
To: Dario Binacchi, linux-kernel
Cc: Alexandre Belloni, Alessandro Zummo, linux-rtc
On Sun, 25 Apr 2021 16:59:23 +0200, Dario Binacchi wrote:
> The RTC_OSC_REG register is 32-bit, but the useful information is found
> in the 7 least significant bits (bits 7-31 are reserved). And in fact,
> as you can see from the code, all read accesses are 8-bit, as well as
> some writes. Let's make sure all writes are 8-bit. Moreover, in contexts
> where consecutive reads / writes after the busy check must take place
> within 15 us, it is better not to waste time on useless accesses.
I really doubt writeb versus writel actually make a difference as the bus will
probably still do a 32bit access.
Applied, thanks!
[1/1] rtc: omap: use rtc_write to access OMAP_RTC_OSC_REG
commit: 50f2cc7f758cdbc7c8f928edc25b1c7bc09ef3e2
Best regards,
--
Alexandre Belloni <alexandre.belloni@bootlin.com>
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