>From 4fd7086f28d6452f1edafa903e7becd5a0f017c6 Mon Sep 17 00:00:00 2001 From: Jiri Pinkava Date: Mon, 11 Apr 2011 03:20:33 +0200 Subject: [PATCH] nand: Fix S3C NAND clock stop Current implementation of s3c2410_nand_select_chip call clk_disable every time when chip = -1 (de-select). This happend multiple times even if chip was already de-selected. This causes disabling clock even if they are already disabled and due to nature of clock subsytem implementation this causes nand clock to be disabled and newer enabled again. Signed-off-by: Jiri Pinkava --- drivers/mtd/nand/s3c2410.c | 57 +++++++++++++++++++++++++++++++------------ 1 files changed, 41 insertions(+), 16 deletions(-) diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c index 33d832d..fbc37dc 100644 --- a/drivers/mtd/nand/s3c2410.c +++ b/drivers/mtd/nand/s3c2410.c @@ -54,8 +54,14 @@ static int hardware_ecc = 1; static int hardware_ecc = 0; #endif +#define CLOCK_DISABLE 0 +#define CLOCK_ENABLE 1 +#define CLOCK_SUSPEND 2 + +static int clock_state = CLOCK_DISABLE; + #ifdef CONFIG_MTD_NAND_S3C2410_CLKSTOP -static int clock_stop = 1; +static const int clock_stop = 1; #else static const int clock_stop = 0; #endif @@ -159,11 +165,33 @@ static struct s3c2410_platform_nand *to_nand_plat(struct platform_device *dev) return dev->dev.platform_data; } -static inline int allow_clk_stop(struct s3c2410_nand_info *info) +static inline int allow_clk_suspend(struct s3c2410_nand_info *info) { return clock_stop; } +/** + * s3c2410_nand_clk_set_state - Enable, disable or suspend NAND clock. + * @info: The controller instance. + * @new_state: State to which clock should be set. + */ +static void s3c2410_nand_clk_set_state(struct s3c2410_nand_info *info, + int new_state) +{ + if (!allow_clk_suspend(info) && new_state == CLOCK_SUSPEND) + return; + + if (clock_state == CLOCK_ENABLE) { + if (new_state != CLOCK_ENABLE) + clk_disable(info->clk); + } else { + if (new_state == CLOCK_ENABLE) + clk_enable(info->clk); + } + + clock_state = new_state; +} + /* timing calculations */ #define NS_IN_KHZ 1000000 @@ -333,8 +361,8 @@ static void s3c2410_nand_select_chip(struct mtd_info *mtd, int chip) nmtd = this->priv; info = nmtd->info; - if (chip != -1 && allow_clk_stop(info)) - clk_enable(info->clk); + if (chip != -1) + s3c2410_nand_clk_set_state(info, CLOCK_ENABLE); cur = readl(info->sel_reg); @@ -356,8 +384,8 @@ static void s3c2410_nand_select_chip(struct mtd_info *mtd, int chip) writel(cur, info->sel_reg); - if (chip == -1 && allow_clk_stop(info)) - clk_disable(info->clk); + if (chip == -1) + s3c2410_nand_clk_set_state(info, CLOCK_SUSPEND); } /* s3c2410_nand_hwcontrol @@ -694,8 +722,7 @@ static int s3c24xx_nand_remove(struct platform_device *pdev) /* free the common resources */ if (info->clk != NULL && !IS_ERR(info->clk)) { - if (!allow_clk_stop(info)) - clk_disable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_DISABLE); clk_put(info->clk); } @@ -947,7 +974,7 @@ static int s3c24xx_nand_probe(struct platform_device *pdev) goto exit_error; } - clk_enable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_ENABLE); /* allocate and map the resource */ @@ -1026,9 +1053,9 @@ static int s3c24xx_nand_probe(struct platform_device *pdev) goto exit_error; } - if (allow_clk_stop(info)) { + if (allow_clk_suspend(info)) { dev_info(&pdev->dev, "clock idle support enabled\n"); - clk_disable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_SUSPEND); } pr_debug("initialised ok\n"); @@ -1059,8 +1086,7 @@ static int s3c24xx_nand_suspend(struct platform_device *dev, pm_message_t pm) writel(info->save_sel | info->sel_bit, info->sel_reg); - if (!allow_clk_stop(info)) - clk_disable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_DISABLE); } return 0; @@ -1072,7 +1098,7 @@ static int s3c24xx_nand_resume(struct platform_device *dev) unsigned long sel; if (info) { - clk_enable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_ENABLE); s3c2410_nand_inithw(info); /* Restore the state of the nFCE line. */ @@ -1082,8 +1108,7 @@ static int s3c24xx_nand_resume(struct platform_device *dev) sel |= info->save_sel & info->sel_bit; writel(sel, info->sel_reg); - if (allow_clk_stop(info)) - clk_disable(info->clk); + s3c2410_nand_clk_set_state(info, CLOCK_SUSPEND); } return 0; -- 1.7.4.4