[PATCH v4] drm/exynos: prepare FIMD clocks

[Vikas Sajjan]

While migrating to common clock framework (CCF), I found that the FIMD clocks
were pulled down by the CCF.
If CCF finds any clock(s) which has NOT been claimed by any of the
drivers, then such clock(s) are PULLed low by CCF.

Calling clk_prepare() for FIMD clocks fixes the issue.

This patch also replaces clk_disable() with clk_unprepare() during exit, since
clk_prepare() is called in fimd_probe().

Signed-off-by: Vikas Sajjan <vikas.sajjan at linaro.org>
---
Changes since v3:
	- added clk_prepare() in fimd_probe() and clk_unprepare() in fimd_remove()
	 as suggested by Viresh Kumar <viresh.kumar at linaro.org>
Changes since v2:
	- moved clk_prepare_enable() and clk_disable_unprepare() from 
	fimd_probe() to fimd_clock() as suggested by Inki Dae <inki.dae at samsung.com>
Changes since v1:
	- added error checking for clk_prepare_enable() and also replaced 
	clk_disable() with clk_disable_unprepare() during exit.
---
 drivers/gpu/drm/exynos/exynos_drm_fimd.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
index 9537761..aa22370 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
@@ -934,6 +934,16 @@ static int fimd_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = clk_prepare(ctx->bus_clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare(ctx->lcd_clk);
+	if  (ret < 0) {
+		clk_unprepare(ctx->bus_clk);
+		return ret;
+	}
+
 	ctx->vidcon0 = pdata->vidcon0;
 	ctx->vidcon1 = pdata->vidcon1;
 	ctx->default_win = pdata->default_win;
@@ -981,8 +991,8 @@ static int fimd_remove(struct platform_device *pdev)
 	if (ctx->suspended)
 		goto out;
 
-	clk_disable(ctx->lcd_clk);
-	clk_disable(ctx->bus_clk);
+	clk_unprepare(ctx->lcd_clk);
+	clk_unprepare(ctx->bus_clk);
 
 	pm_runtime_set_suspended(dev);
 	pm_runtime_put_sync(dev);
-- 
1.7.9.5