[ARM] Fix pxamci regression

Fix:

WARNING: at arch/arm/mach-pxa/clock.c:69 clk_disable()
[<c002d7c8>] (dump_stack+0x0/0x14) from [<c00334f4>] (clk_disable+0x34/0xa0)
[<c00334c0>] (clk_disable+0x0/0xa0) from [<c028a43c>] (pxamci_set_ios+0x74/0xf0)
[<c028a3c8>] (pxamci_set_ios+0x0/0xf0) from [<c0281548>] (mmc_power_off+0x90/0x9c)
[<c02814b8>] (mmc_power_off+0x0/0x9c) from [<c0281a30>] (mmc_start_host+0x18/0x28)
[<c0281a18>] (mmc_start_host+0x0/0x28) from [<c02825a0>] (mmc_add_host+0xe8/0x104)
[<c02824b8>] (mmc_add_host+0x0/0x104) from [<c028a7d0>] (pxamci_probe+0x24c/0x2f4)
[<c028a584>] (pxamci_probe+0x0/0x2f4) from [<c01e5948>] (platform_drv_probe+0x20/0x24)
...

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/mmc/host/pxamci.c b/drivers/mmc/host/pxamci.c
index a25ee71998a9..1654a3330340 100644
--- a/drivers/mmc/host/pxamci.c
+++ b/drivers/mmc/host/pxamci.c
@@ -39,6 +39,7 @@
 #define DRIVER_NAME     "pxa2xx-mci"
 
 #define NR_SG   1
+#define CLKRT_OFF       (~0)
 
 struct pxamci_host {
         struct mmc_host         *mmc;
@@ -371,6 +372,9 @@ static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                 unsigned long rate = host->clkrate;
                 unsigned int clk = rate / ios->clock;
 
+                if (host->clkrt == CLKRT_OFF)
+                        clk_enable(host->clk);
+
                 /*
                  * clk might result in a lower divisor than we
                  * desire.  check for that condition and adjust
@@ -379,14 +383,16 @@ static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                 if (rate / clk > ios->clock)
                         clk <<= 1;
                 host->clkrt = fls(clk) - 1;
-                clk_enable(host->clk);
 
                 /*
                  * we write clkrt on the next command
                  */
         } else {
                 pxamci_stop_clock(host);
-                clk_disable(host->clk);
+                if (host->clkrt != CLKRT_OFF) {
+                        host->clkrt = CLKRT_OFF;
+                        clk_disable(host->clk);
+                }
         }
 
         if (host->power_mode != ios->power_mode) {
@@ -498,6 +504,7 @@ static int pxamci_probe(struct platform_device *pdev)
         host->mmc = mmc;
         host->dma = -1;
         host->pdata = pdev->dev.platform_data;
+        host->clkrt = CLKRT_OFF;
 
         host->clk = clk_get(&pdev->dev, "MMCCLK");
         if (IS_ERR(host->clk)) {