mtd: nand: clk: preparation for switch to common clock framework

As a first step towards migrating davinci platforms to use common clock
framework, replace all instances of clk_enable() with clk_prepare_enable()
and clk_disable() with clk_disable_unprepare(). Until the platform is
switched to use the CONFIG_HAVE_CLK_PREPARE Kconfig variable, this just
adds a might_sleep() call and would work without any issues.

This will make it easy later to switch to common clk based implementation
of clk driver from DaVinci specific driver.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/davinci_nand.c

@@ -724,7 +724,7 @@ static int __init nand_davinci_probe(struct platform_device *pdev)
 		goto err_clk;
 	}
 
-	ret = clk_enable(info->clk);
+	ret = clk_prepare_enable(info->clk);
 	if (ret < 0) {
 		dev_dbg(&pdev->dev, "unable to enable AEMIF clock, err %d\n",
 			ret);
@@ -835,7 +835,7 @@ syndrome_done:
 
 err_scan:
 err_timing:
-	clk_disable(info->clk);
+	clk_disable_unprepare(info->clk);
 
 err_clk_enable:
 	clk_put(info->clk);
@@ -872,7 +872,7 @@ static int __exit nand_davinci_remove(struct platform_device *pdev)
 
 	nand_release(&info->mtd);
 
-	clk_disable(info->clk);
+	clk_disable_unprepare(info->clk);
 	clk_put(info->clk);
 
 	kfree(info);