The patch titled
spi_s3c24xx: fix clock rate calculation
has been removed from the -mm tree. Its filename was
spi_s3c24xx-fix-clock-rate-calculation.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: spi_s3c24xx: fix clock rate calculation
From: Ben Dooks <ben@xxxxxxxxxxxx>
Currently the clock rate calculation may round as pleased, which means
that it is possible that we will round down and end up with a faster clock
rate than intended.
Change the calculation to use DIV_ROUND_UP() to ensure that we end up with
a clock rate either the same as or lower than the user requested one.
Signed-off-by: Ben Dooks <ben@xxxxxxxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi_s3c24xx.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff -puN drivers/spi/spi_s3c24xx.c~spi_s3c24xx-fix-clock-rate-calculation drivers/spi/spi_s3c24xx.c
--- a/drivers/spi/spi_s3c24xx.c~spi_s3c24xx-fix-clock-rate-calculation
+++ a/drivers/spi/spi_s3c24xx.c
@@ -111,6 +111,7 @@ static int s3c24xx_spi_setupxfer(struct
unsigned int bpw;
unsigned int hz;
unsigned int div;
+ unsigned long clk;
bpw = t ? t->bits_per_word : spi->bits_per_word;
hz = t ? t->speed_hz : spi->max_speed_hz;
@@ -120,20 +121,16 @@ static int s3c24xx_spi_setupxfer(struct
return -EINVAL;
}
- div = clk_get_rate(hw->clk) / hz;
-
- /* is clk = pclk / (2 * (pre+1)), or is it
- * clk = (pclk * 2) / ( pre + 1) */
-
- div /= 2;
-
- if (div > 0)
- div -= 1;
+ clk = clk_get_rate(hw->clk);
+ div = DIV_ROUND_UP(clk, hz * 2) - 1;
if (div > 255)
div = 255;
- dev_dbg(&spi->dev, "setting pre-scaler to %d (hz %d)\n", div, hz);
+ dev_dbg(&spi->dev, "setting pre-scaler to %d (wanted %d, got %ld)\n",
+ div, hz, clk / (2 * (div + 1)));
+
+
writeb(div, hw->regs + S3C2410_SPPRE);
spin_lock(&hw->bitbang.lock);
_
Patches currently in -mm which might be from ben@xxxxxxxxxxxx are
origin.patch
linux-next.patch
spi-fix-spelling-of-automatically-in-documentation.patch
spi_s3c24xx-fix-header-includes.patch
spi_s3c24xx-use-resource_size-to-get-resource-size.patch
spi_s3c24xx-use-dev_pm_ops.patch
spi_s3c24xx-cache-device-setup-data.patch
gpiolib-add-names-file-in-gpio-chip-sysfs.patch
gpiolib-add-names-file-in-gpio-chip-sysfs-checkpatch-fixes.patch
gpiolib-add-names-file-in-gpio-chip-sysfs-checkpatch-fixes-fix.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
