From: Silvan Wicki <linux_wi-ADq4ffItWIY@public.gmane.org>
To: wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org
Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Silvan Wicki <linux_wi-ADq4ffItWIY@public.gmane.org>
Subject: [PATCH] i2c: i2c-bcm2708: fixes cdiv uneven number
Date: Thu, 30 Apr 2015 20:07:46 +0200 [thread overview]
Message-ID: <1430417266-14900-1-git-send-email-linux_wi@tinag.ch> (raw)
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
next reply other threads:[~2015-04-30 18:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-30 18:07 Silvan Wicki [this message]
[not found] ` <1430417266-14900-1-git-send-email-linux_wi-ADq4ffItWIY@public.gmane.org>
2015-05-01 5:24 ` [PATCH] i2c: i2c-bcm2708: fixes cdiv uneven number rajeev kumar
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