[PATCH 06/10] clk: amlogic: PLL reset signal supports active-low configuration

[Jian Hu via B4 Relay]

From: Jian Hu <jian.hu at amlogic.com>

In the A9 design, the PLL reset signal is configured as active-low.

Add the flag 'CLK_MESON_PLL_RST_N' to indicate that the PLL reset signal
is active-low.

Signed-off-by: Jian Hu <jian.hu at amlogic.com>
---
 drivers/clk/meson/clk-pll.c | 42 +++++++++++++++++++++++++++++++-----------
 drivers/clk/meson/clk-pll.h |  2 ++
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
index 5a0bd75f85a9..8568ad6ba7b6 100644
--- a/drivers/clk/meson/clk-pll.c
+++ b/drivers/clk/meson/clk-pll.c
@@ -295,10 +295,14 @@ static int meson_clk_pll_is_enabled(struct clk_hw *hw)
 {
 	struct clk_regmap *clk = to_clk_regmap(hw);
 	struct meson_clk_pll_data *pll = meson_clk_pll_data(clk);
+	unsigned int rst;
 
-	if (MESON_PARM_APPLICABLE(&pll->rst) &&
-	    meson_parm_read(clk->map, &pll->rst))
-		return 0;
+	if (MESON_PARM_APPLICABLE(&pll->rst)) {
+		rst = meson_parm_read(clk->map, &pll->rst);
+		if ((rst && !(pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)) ||
+		    (!rst && (pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)))
+			return 0;
+	}
 
 	if (!meson_parm_read(clk->map, &pll->en) ||
 	    !meson_parm_read(clk->map, &pll->l))
@@ -326,14 +330,22 @@ static int meson_clk_pll_init(struct clk_hw *hw)
 		return 0;
 
 	if (pll->init_count) {
-		if (MESON_PARM_APPLICABLE(&pll->rst))
-			meson_parm_write(clk->map, &pll->rst, 1);
+		if (MESON_PARM_APPLICABLE(&pll->rst)) {
+			if (pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)
+				meson_parm_write(clk->map, &pll->rst, 0);
+			else
+				meson_parm_write(clk->map, &pll->rst, 1);
+		}
 
 		regmap_multi_reg_write(clk->map, pll->init_regs,
 				       pll->init_count);
 
-		if (MESON_PARM_APPLICABLE(&pll->rst))
-			meson_parm_write(clk->map, &pll->rst, 0);
+		if (MESON_PARM_APPLICABLE(&pll->rst)) {
+			if (pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)
+				meson_parm_write(clk->map, &pll->rst, 1);
+			else
+				meson_parm_write(clk->map, &pll->rst, 0);
+		}
 	}
 
 	return 0;
@@ -363,15 +375,23 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
 		return 0;
 
 	/* Make sure the pll is in reset */
-	if (MESON_PARM_APPLICABLE(&pll->rst))
-		meson_parm_write(clk->map, &pll->rst, 1);
+	if (MESON_PARM_APPLICABLE(&pll->rst)) {
+		if (pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)
+			meson_parm_write(clk->map, &pll->rst, 0);
+		else
+			meson_parm_write(clk->map, &pll->rst, 1);
+	}
 
 	/* Enable the pll */
 	meson_parm_write(clk->map, &pll->en, 1);
 
 	/* Take the pll out reset */
-	if (MESON_PARM_APPLICABLE(&pll->rst))
-		meson_parm_write(clk->map, &pll->rst, 0);
+	if (MESON_PARM_APPLICABLE(&pll->rst)) {
+		if (pll->flags & CLK_MESON_PLL_RST_ACTIVE_LOW)
+			meson_parm_write(clk->map, &pll->rst, 1);
+		else
+			meson_parm_write(clk->map, &pll->rst, 0);
+	}
 
 	/*
 	 * Compared with the previous SoCs, self-adaption current module
diff --git a/drivers/clk/meson/clk-pll.h b/drivers/clk/meson/clk-pll.h
index 97b7c70376a3..1be7e6e77631 100644
--- a/drivers/clk/meson/clk-pll.h
+++ b/drivers/clk/meson/clk-pll.h
@@ -31,6 +31,8 @@ struct pll_mult_range {
 #define CLK_MESON_PLL_NOINIT_ENABLED	BIT(1)
 /* l_detect signal is active-high */
 #define CLK_MESON_PLL_L_DETECT_ACTIVE_HIGH	BIT(2)
+/* rst signal is active-low (Power-on reset) */
+#define CLK_MESON_PLL_RST_ACTIVE_LOW	BIT(3)
 
 struct meson_clk_pll_data {
 	struct parm en;

-- 
2.47.1