[PATCH] clk: samsung: Fix Exynos 5420 pinctrl setup and clock disable failure due to domain being gated
From: Krzysztof Kozlowski <hidden>
Date: 2014-12-05 14:22:00
Audio subsystem clocks are located in separate block. On Exynos 5420 if clock for this block (from main clock domain) 'mau_epll' is gated then any read or write to audss registers will block. This kind of boot hang was observed on Arndale Octa and Peach Pi/Pit after introducing runtime PM to pl330 DMA driver. After that commit the 'mau_epll' was gated, because the "amba" clock was disabled and there were no more users of mau_epll. The system hang on one of steps: 1. Disabling unused clocks from audss block. 2. During audss GPIO setup (just before probing i2s0 because samsung_pinmux_setup() tried to access memory from audss block which was gated. Add a workaround for this by enabling the 'mau_epll' clock in probe. Signed-off-by: Krzysztof Kozlowski <redacted> --- drivers/clk/samsung/clk-exynos-audss.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/samsung/clk-exynos-audss.c b/drivers/clk/samsung/clk-exynos-audss.c
index acce708ace18..0916a81fa932 100644
--- a/drivers/clk/samsung/clk-exynos-audss.c
+++ b/drivers/clk/samsung/clk-exynos-audss.c@@ -29,6 +29,13 @@ static DEFINE_SPINLOCK(lock); static struct clk **clk_table; static void __iomem *reg_base; static struct clk_onecell_data clk_data; +/* + * On Exynos5420 this will be a clock which has to be enabled before any + * access to audss registers. Typically a child of EPLL. + * + * On other platforms this will be -ENODEV. + */ +static struct clk *epll; #define ASS_CLK_SRC 0x0 #define ASS_CLK_DIV 0x4
@@ -98,6 +105,8 @@ static int exynos_audss_clk_probe(struct platform_device *pdev) dev_err(&pdev->dev, "failed to map audss registers\n"); return PTR_ERR(reg_base); } + /* EPLL don't have to be enabled for boards other than Exynos5420 */ + epll = ERR_PTR(-ENODEV); clk_table = devm_kzalloc(&pdev->dev, sizeof(struct clk *) * EXYNOS_AUDSS_MAX_CLKS,
@@ -115,8 +124,20 @@ static int exynos_audss_clk_probe(struct platform_device *pdev) pll_in = devm_clk_get(&pdev->dev, "pll_in"); if (!IS_ERR(pll_ref)) mout_audss_p[0] = __clk_get_name(pll_ref); - if (!IS_ERR(pll_in)) + if (!IS_ERR(pll_in)) { mout_audss_p[1] = __clk_get_name(pll_in); + + if (variant == TYPE_EXYNOS5420) { + epll = pll_in; + + ret = clk_prepare_enable(epll); + if (ret) { + dev_err(&pdev->dev, + "failed to prepare the epll clock\n"); + return ret; + } + } + } clk_table[EXYNOS_MOUT_AUDSS] = clk_register_mux(NULL, "mout_audss", mout_audss_p, ARRAY_SIZE(mout_audss_p), CLK_SET_RATE_NO_REPARENT,
@@ -203,6 +224,9 @@ unregister: clk_unregister(clk_table[i]); } + if (!IS_ERR(epll)) + clk_disable_unprepare(epll); + return ret; }
@@ -217,6 +241,9 @@ static int exynos_audss_clk_remove(struct platform_device *pdev) clk_unregister(clk_table[i]); } + if (!IS_ERR(epll)) + clk_disable_unprepare(epll); + return 0; }
--
1.9.1