linux-kernel - [PATCH 4.13 157/160] clk: samsung: exynos4: Enable VPLL and EPLL clocks for suspend/resume cycle

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Date:   Tue, 10 Oct 2017 21:51:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Stephen Boyd <sboyd@...eaurora.org>
Subject: [PATCH 4.13 157/160] clk: samsung: exynos4: Enable VPLL and EPLL clocks for suspend/resume cycle

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marek Szyprowski <m.szyprowski@...sung.com>

commit 5dcbeca615ef12047a5f4097b91030cbf995b1d2 upstream.

Commit 6edfa11cb396 ("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: 6edfa11cb396 ("clk: samsung: Add enable/disable operation for PLL36XX clocks")
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@...sung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@...nel.org>
Acked-by: Sylwester Nawrocki <s.nawrocki@...sung.com>
Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/clk/samsung/clk-exynos4.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

--- a/drivers/clk/samsung/clk-exynos4.c
+++ b/drivers/clk/samsung/clk-exynos4.c
@@ -294,6 +294,18 @@ static const struct samsung_clk_reg_dump
 #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));