clk: samsung: exynos4: Enable VPLL and EPLL clocks for suspend/resume cycle

Commit 6edfa11c ("clk: samsung: Add enable/disable operation for
PLL36XX clocks") added enable/disable operations to PLL clocks. Prior that
VPLL and EPPL clocks were always enabled because the enable bit was never
touched. Those clocks have to be enabled during suspend/resume cycle,
because otherwise board fails to enter sleep mode. This patch enables them
unconditionally before entering system suspend state. System restore
function will set them to the previous state saved in the register cache
done before that unconditional enable.

Fixes: 6edfa11c ("clk: samsung: Add enable/disable operation for PLL36XX clocks")
CC: stable@vger.kernel.org # v4.13
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NChanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: NKrzysztof Kozlowski <krzk@kernel.org>
Acked-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

drivers/clk/samsung/clk-exynos4.c

@@ -294,6 +294,18 @@ static const struct samsung_clk_reg_dump src_mask_suspend_e4210[] = {
 #define PLL_ENABLED	(1 << 31)
 #define PLL_LOCKED	(1 << 29)
 
+static void exynos4_clk_enable_pll(u32 reg)
+{
+	u32 pll_con = readl(reg_base + reg);
+	pll_con |= PLL_ENABLED;
+	writel(pll_con, reg_base + reg);
+
+	while (!(pll_con & PLL_LOCKED)) {
+		cpu_relax();
+		pll_con = readl(reg_base + reg);
+	}
+}
+
 static void exynos4_clk_wait_for_pll(u32 reg)
 {
 	u32 pll_con;
@@ -315,6 +327,9 @@ static int exynos4_clk_suspend(void)
 	samsung_clk_save(reg_base, exynos4_save_pll,
 				ARRAY_SIZE(exynos4_clk_pll_regs));
 
+	exynos4_clk_enable_pll(EPLL_CON0);
+	exynos4_clk_enable_pll(VPLL_CON0);
+
 	if (exynos4_soc == EXYNOS4210) {
 		samsung_clk_save(reg_base, exynos4_save_soc,
 					ARRAY_SIZE(exynos4210_clk_save));