lkml.org 
[lkml]   [2014]   [Aug]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] spi/rockchip: Avoid accidentally turning off the clock
Date
If our client is requesting a clock that is above the maximum clock
then the following division will result in 0:
rs->max_freq / rs->speed

We'll then program 0 into the SPI_BAUDR register. The Rockchip TRM
says: "If the value is 0, the serial output clock (sclk_out) is
disabled."

It's much better to end up with the fastest possible clock rather than
a clock that is off, so enforce a minimum value.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
drivers/spi/spi-rockchip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 6321326..cd0e08b0 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -499,7 +499,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
}

/* div doesn't support odd number */
- div = rs->max_freq / rs->speed;
+ div = max_t(u32, rs->max_freq / rs->speed, 1);
div = (div + 1) & 0xfffe;

spi_enable_chip(rs, 0);
--
2.1.0.rc2.206.gedb03e5


\
 
 \ /
  Last update: 2014-08-29 02:01    [W:0.039 / U:0.292 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site