From mboxrd@z Thu Jan 1 00:00:00 1970 From: jbe@pengutronix.de (Juergen Beisert) Date: Tue, 8 Dec 2009 13:01:25 +0100 Subject: [PATCH] [NAND] S3C2410: Fix NFC clock enable/disable imbalance (2nd try) In-Reply-To: <200912081123.06630.jbe@pengutronix.de> References: <200912081056.40210.jbe@pengutronix.de> <200912081123.06630.jbe@pengutronix.de> Message-ID: <200912081301.25597.jbe@pengutronix.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org When unmounting an mtd filesystem the s3c2410_nand_select_chip() function gets called again with "chip == -1". In this case the current code disables the NFC clock at least a second time, so it does not work anymore. Clock disabling should only happen if it was really enabled. Due to a lack of a query function if a clock is already enabled (and how often), we must count enable/disable calls by our own here. Note: Other enable/disable sequences can be found in the power management functions. I'm not sure if they interfere with this local enable/disable count. Signed-off-by: Juergen Beisert Acked-by: Wolfram Sang --- drivers/mtd/nand/s3c2410.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) Index: linux-2.6.32/drivers/mtd/nand/s3c2410.c =================================================================== --- linux-2.6.32.orig/drivers/mtd/nand/s3c2410.c +++ linux-2.6.32/drivers/mtd/nand/s3c2410.c @@ -329,12 +329,15 @@ static void s3c2410_nand_select_chip(str struct s3c2410_nand_mtd *nmtd; struct nand_chip *this = mtd->priv; unsigned long cur; + static int clock_enable_cnt = 0; nmtd = this->priv; info = nmtd->info; - if (chip != -1 && allow_clk_stop(info)) + if (chip != -1 && allow_clk_stop(info)) { clk_enable(info->clk); + clock_enable_cnt++; + } cur = readl(info->sel_reg); @@ -356,8 +359,10 @@ static void s3c2410_nand_select_chip(str writel(cur, info->sel_reg); - if (chip == -1 && allow_clk_stop(info)) + if (chip == -1 && allow_clk_stop(info) && clock_enable_cnt > 0) { clk_disable(info->clk); + clock_enable_cnt--; + } } /* s3c2410_nand_hwcontrol -- Pengutronix e.K. | Juergen Beisert | Linux Solutions for Science and Industry | Phone: +49-8766-939 228 | Vertretung Sued/Muenchen, Germany | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de/ |