* [PATCH] i2c: i2c-bcm2708: fixes cdiv uneven number
@ 2015-04-30 18:07 Silvan Wicki
[not found] ` <1430417266-14900-1-git-send-email-linux_wi-ADq4ffItWIY@public.gmane.org>
0 siblings, 1 reply; 2+ messages in thread
From: Silvan Wicki @ 2015-04-30 18:07 UTC (permalink / raw)
To: wsa-z923LK4zBo2bacvFa/9K2g; +Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA, Silvan Wicki
Prevents that cdiv can be an uneven number as per datasheet cdiv is
always rounded down to an even number.
Datasheet at page 34 on
http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
Signed-off-by: Silvan Wicki <linux_wi-ADq4ffItWIY@public.gmane.org>
---
drivers/i2c/busses/i2c-bcm2708.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c
index 81e9374..454ab48 100644
--- a/drivers/i2c/busses/i2c-bcm2708.c
+++ b/drivers/i2c/busses/i2c-bcm2708.c
@@ -441,9 +441,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
bus_hz = clk_get_rate(bi->clk);
cdiv = bus_hz / baudrate;
- if (cdiv > 0xffff) {
- cdiv = 0xffff;
+ /* as per datasheet cdiv is always rounded down to an even number */
+ if (cdiv > 0xfffe) {
+ cdiv = 0xfffe;
baudrate = bus_hz / cdiv;
+ } else {
+ if ((cdiv & 0xfffe) != cdiv) {
+ cdiv &= 0xfffe;
+ baudrate = bus_hz / cdiv;
+ }
}
bi->cdiv = cdiv;
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread[parent not found: <1430417266-14900-1-git-send-email-linux_wi-ADq4ffItWIY@public.gmane.org>]
* Re: [PATCH] i2c: i2c-bcm2708: fixes cdiv uneven number [not found] ` <1430417266-14900-1-git-send-email-linux_wi-ADq4ffItWIY@public.gmane.org> @ 2015-05-01 5:24 ` rajeev kumar 0 siblings, 0 replies; 2+ messages in thread From: rajeev kumar @ 2015-05-01 5:24 UTC (permalink / raw) To: Silvan Wicki; +Cc: Wolfram Sang, linux-i2c-u79uwXL29TY76Z2rM5mHXA On Thu, Apr 30, 2015 at 11:37 PM, Silvan Wicki <linux_wi-ADq4ffItWIY@public.gmane.org> wrote: > Prevents that cdiv can be an uneven number as per datasheet cdiv is > always rounded down to an even number. > > Datasheet at page 34 on > http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > > Signed-off-by: Silvan Wicki <linux_wi-ADq4ffItWIY@public.gmane.org> > --- > drivers/i2c/busses/i2c-bcm2708.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c > index 81e9374..454ab48 100644 > --- a/drivers/i2c/busses/i2c-bcm2708.c > +++ b/drivers/i2c/busses/i2c-bcm2708.c > @@ -441,9 +441,15 @@ static int bcm2708_i2c_probe(struct platform_device *pdev) > > bus_hz = clk_get_rate(bi->clk); > cdiv = bus_hz / baudrate; > - if (cdiv > 0xffff) { > - cdiv = 0xffff; > + /* as per datasheet cdiv is always rounded down to an even number */ > + if (cdiv > 0xfffe) { > + cdiv = 0xfffe; Use #define ~Rajeev > baudrate = bus_hz / cdiv; > + } else { > + if ((cdiv & 0xfffe) != cdiv) { > + cdiv &= 0xfffe; > + baudrate = bus_hz / cdiv; > + } > } > bi->cdiv = cdiv; > > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 2+ messages in thread
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2015-04-30 18:07 [PATCH] i2c: i2c-bcm2708: fixes cdiv uneven number Silvan Wicki
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2015-05-01 5:24 ` rajeev kumar
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