-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
mmc: spi: Pull out the SSP clock configuration function
Pull out the MMC clock configuration function and make it into SSP clock configuration function, so it can be used by the SPI driver too. Signed-off-by: Marek Vasut <marex@denx.de> Acked-by: Chris Ball <cjb@laptop.org> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
- Loading branch information
Marek Vasut
authored and
Mark Brown
committed
Aug 17, 2012
1 parent
829c1bf
commit 1308239
Showing
4 changed files
with
66 additions
and
39 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,62 @@ | ||
/* | ||
* Copyright 2012 DENX Software Engineering, GmbH | ||
* | ||
* Pulled from code: | ||
* Portions copyright (C) 2003 Russell King, PXA MMCI Driver | ||
* Portions copyright (C) 2004-2005 Pierre Ossman, W83L51xD SD/MMC driver | ||
* | ||
* Copyright 2008 Embedded Alley Solutions, Inc. | ||
* Copyright 2009-2011 Freescale Semiconductor, Inc. | ||
* | ||
* The code contained herein is licensed under the GNU General Public | ||
* License. You may obtain a copy of the GNU General Public License | ||
* Version 2 or later at the following locations: | ||
* | ||
* http://www.opensource.org/licenses/gpl-license.html | ||
* http://www.gnu.org/copyleft/gpl.html | ||
*/ | ||
|
||
#include <linux/kernel.h> | ||
#include <linux/init.h> | ||
#include <linux/clk.h> | ||
#include <linux/module.h> | ||
#include <linux/device.h> | ||
#include <linux/io.h> | ||
#include <linux/spi/mxs-spi.h> | ||
|
||
void mxs_ssp_set_clk_rate(struct mxs_ssp *ssp, unsigned int rate) | ||
{ | ||
unsigned int ssp_clk, ssp_sck; | ||
u32 clock_divide, clock_rate; | ||
u32 val; | ||
|
||
ssp_clk = clk_get_rate(ssp->clk); | ||
|
||
for (clock_divide = 2; clock_divide <= 254; clock_divide += 2) { | ||
clock_rate = DIV_ROUND_UP(ssp_clk, rate * clock_divide); | ||
clock_rate = (clock_rate > 0) ? clock_rate - 1 : 0; | ||
if (clock_rate <= 255) | ||
break; | ||
} | ||
|
||
if (clock_divide > 254) { | ||
dev_err(ssp->dev, | ||
"%s: cannot set clock to %d\n", __func__, rate); | ||
return; | ||
} | ||
|
||
ssp_sck = ssp_clk / clock_divide / (1 + clock_rate); | ||
|
||
val = readl(ssp->base + HW_SSP_TIMING(ssp)); | ||
val &= ~(BM_SSP_TIMING_CLOCK_DIVIDE | BM_SSP_TIMING_CLOCK_RATE); | ||
val |= BF_SSP(clock_divide, TIMING_CLOCK_DIVIDE); | ||
val |= BF_SSP(clock_rate, TIMING_CLOCK_RATE); | ||
writel(val, ssp->base + HW_SSP_TIMING(ssp)); | ||
|
||
ssp->clk_rate = ssp_sck; | ||
|
||
dev_dbg(ssp->dev, | ||
"%s: clock_divide %d, clock_rate %d, ssp_clk %d, rate_actual %d, rate_requested %d\n", | ||
__func__, clock_divide, clock_rate, ssp_clk, ssp_sck, rate); | ||
} | ||
EXPORT_SYMBOL_GPL(mxs_ssp_set_clk_rate); |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters