[MTD NAND] s3c24x0 board: Fix clock handling, ensure proper initialisation.
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linux-mtd at lists.infradead.org
Mon Jun 19 04:59:02 EDT 2006
Commit: d1fef3c5e16327661be6cb127d68f5be379697a5
Parent: 1046d88001e7b8819f60dece2eaf1b44bf4b4460
commit d1fef3c5e16327661be6cb127d68f5be379697a5
Author: Ben Dooks <ben-linux at fluff.org>
AuthorDate: Mon Jun 19 09:29:38 2006 +0100
Commit: David Woodhouse <dwmw2 at infradead.org>
CommitDate: Mon Jun 19 09:29:38 2006 +0100
[MTD NAND] s3c24x0 board: Fix clock handling, ensure proper initialisation.
Signed-off-by: Ben Dooks <ben-linux at fluff.org>
Signed-off-by: David Woodhouse <dwmw2 at infradead.org>
---
drivers/mtd/nand/Kconfig | 10 ++++++
drivers/mtd/nand/s3c2410.c | 76 +++++++++++++++++++++++++++++++++++++++++---
2 files changed, 81 insertions(+), 5 deletions(-)
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 203f90a..3db77ee 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -135,6 +135,16 @@ config MTD_NAND_NDFC
help
NDFC Nand Flash Controllers are integrated in EP44x SoCs
+config MTD_NAND_S3C2410_CLKSTOP
+ bool "S3C2410 NAND IDLE clock stop"
+ depends on MTD_NAND_S3C2410
+ default n
+ help
+ Stop the clock to the NAND controller when there is no chip
+ selected to save power. This will mean there is a small delay
+ when the is NAND chip selected or released, but will save
+ approximately 5mA of power when there is nothing happening.
+
config MTD_NAND_DISKONCHIP
tristate "DiskOnChip 2000, Millennium and Millennium Plus (NAND reimplementation) (EXPERIMENTAL)"
depends on MTD_NAND && EXPERIMENTAL
diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
index d6365a6..fd78fb8 100644
--- a/drivers/mtd/nand/s3c2410.c
+++ b/drivers/mtd/nand/s3c2410.c
@@ -18,8 +18,9 @@
* 20-Jun-2005 BJD Updated s3c2440 support, fixed timing bug
* 08-Jul-2005 BJD Fix OOPS when no platform data supplied
* 20-Oct-2005 BJD Fix timing calculation bug
+ * 14-Jan-2006 BJD Allow clock to be stopped when idle
*
- * $Id: s3c2410.c,v 1.20 2005/11/07 11:14:31 gleixner Exp $
+ * $Id: s3c2410.c,v 1.23 2006/04/01 18:06:29 bjd Exp $
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -36,9 +37,6 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
-#include <config/mtd/nand/s3c2410/hwecc.h>
-#include <config/mtd/nand/s3c2410/debug.h>
-
#ifdef CONFIG_MTD_NAND_S3C2410_DEBUG
#define DEBUG
#endif
@@ -73,6 +71,13 @@ #else
static int hardware_ecc = 0;
#endif
+#ifdef CONFIG_MTD_NAND_S3C2410_CLKSTOP
+static int clock_stop = 1;
+#else
+static const int clock_stop = 0;
+#endif
+
+
/* new oob placement block for use with hardware ecc generation
*/
@@ -134,6 +139,11 @@ static struct s3c2410_platform_nand *to_
return dev->dev.platform_data;
}
+static inline int allow_clk_stop(struct s3c2410_nand_info *info)
+{
+ return clock_stop;
+}
+
/* timing calculations */
#define NS_IN_KHZ 1000000
@@ -201,6 +211,11 @@ static int s3c2410_nand_inithw(struct s3
cfg = S3C2440_NFCONF_TACLS(tacls - 1);
cfg |= S3C2440_NFCONF_TWRPH0(twrph0 - 1);
cfg |= S3C2440_NFCONF_TWRPH1(twrph1 - 1);
+
+ /* enable the controller and de-assert nFCE */
+
+ writel(S3C2440_NFCONT_ENABLE | S3C2440_NFCONT_ENABLE,
+ info->regs + S3C2440_NFCONT);
}
pr_debug(PFX "NF_CONF is 0x%lx\n", cfg);
@@ -226,6 +241,9 @@ static void s3c2410_nand_select_chip(str
bit = (info->is_s3c2440) ? S3C2440_NFCONT_nFCE : S3C2410_NFCONF_nFCE;
reg = info->regs + ((info->is_s3c2440) ? S3C2440_NFCONT : S3C2410_NFCONF);
+ if (chip != -1 && allow_clk_stop(info))
+ clk_enable(info->clk);
+
cur = readl(reg);
if (chip == -1) {
@@ -245,6 +263,9 @@ static void s3c2410_nand_select_chip(str
}
writel(cur, reg);
+
+ if (chip == -1 && allow_clk_stop(info))
+ clk_disable(info->clk);
}
/* command and control functions
@@ -417,7 +438,8 @@ static int s3c2410_nand_remove(struct pl
/* free the common resources */
if (info->clk != NULL && !IS_ERR(info->clk)) {
- clk_disable(info->clk);
+ if (!allow_clk_stop(info))
+ clk_disable(info->clk);
clk_put(info->clk);
}
@@ -627,6 +649,11 @@ static int s3c24xx_nand_probe(struct pla
sets++;
}
+ if (allow_clk_stop(info)) {
+ dev_info(&pdev->dev, "clock idle support enabled\n");
+ clk_disable(info->clk);
+ }
+
pr_debug("initialised ok\n");
return 0;
@@ -638,6 +665,41 @@ static int s3c24xx_nand_probe(struct pla
return err;
}
+/* PM Support */
+#ifdef CONFIG_PM
+
+static int s3c24xx_nand_suspend(struct platform_device *dev, pm_message_t pm)
+{
+ struct s3c2410_nand_info *info = platform_get_drvdata(dev);
+
+ if (info) {
+ if (!allow_clk_stop(info))
+ clk_disable(info->clk);
+ }
+
+ return 0;
+}
+
+static int s3c24xx_nand_resume(struct platform_device *dev)
+{
+ struct s3c2410_nand_info *info = platform_get_drvdata(dev);
+
+ if (info) {
+ clk_enable(info->clk);
+ s3c2410_nand_inithw(info, dev);
+
+ if (allow_clk_stop(info))
+ clk_disable(info->clk);
+ }
+
+ return 0;
+}
+
+#else
+#define s3c24xx_nand_suspend NULL
+#define s3c24xx_nand_resume NULL
+#endif
+
/* driver device registration */
static int s3c2410_nand_probe(struct platform_device *dev)
@@ -653,6 +715,8 @@ static int s3c2440_nand_probe(struct pla
static struct platform_driver s3c2410_nand_driver = {
.probe = s3c2410_nand_probe,
.remove = s3c2410_nand_remove,
+ .suspend = s3c24xx_nand_suspend,
+ .resume = s3c24xx_nand_resume,
.driver = {
.name = "s3c2410-nand",
.owner = THIS_MODULE,
@@ -662,6 +726,8 @@ static struct platform_driver s3c2410_na
static struct platform_driver s3c2440_nand_driver = {
.probe = s3c2440_nand_probe,
.remove = s3c2410_nand_remove,
+ .suspend = s3c24xx_nand_suspend,
+ .resume = s3c24xx_nand_resume,
.driver = {
.name = "s3c2440-nand",
.owner = THIS_MODULE,
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