linux-kernel - [PATCH v2 2/6] clk: ingenic: Make PLL clock enable_bit and stable

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Date:   Wed, 26 Oct 2022 20:43:41 +0100
From:   Aidan MacDonald <aidanmacdonald.0x0@...il.com>
To:     paul@...pouillou.net, mturquette@...libre.com, sboyd@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org
Cc:     zhouyu@...yeetech.com, linux-mips@...r.kernel.org,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/6] clk: ingenic: Make PLL clock enable_bit and stable_bit optional

When the enable bit is undefined, the clock is assumed to be always
on and enable/disable is a no-op. When the stable bit is undefined,
the PLL stable check is a no-op.

Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@...il.com>
---
 drivers/clk/ingenic/cgu.c | 14 +++++++++++++-
 drivers/clk/ingenic/cgu.h | 10 ++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/ingenic/cgu.c b/drivers/clk/ingenic/cgu.c
index 3481129114b1..aea01b6b2764 100644
--- a/drivers/clk/ingenic/cgu.c
+++ b/drivers/clk/ingenic/cgu.c
@@ -189,6 +189,9 @@ static inline int ingenic_pll_check_stable(struct ingenic_cgu *cgu,
 {
 	u32 ctl;
 
+	if (pll_info->stable_bit < 0)
+		return 0;
+
 	return readl_poll_timeout(cgu->base + pll_info->reg, ctl,
 				  ctl & BIT(pll_info->stable_bit),
 				  0, 100 * USEC_PER_MSEC);
@@ -230,7 +233,7 @@ ingenic_pll_set_rate(struct clk_hw *hw, unsigned long req_rate,
 	writel(ctl, cgu->base + pll_info->reg);
 
 	/* If the PLL is enabled, verify that it's stable */
-	if (ctl & BIT(pll_info->enable_bit))
+	if (pll_info->enable_bit >= 0 && (ctl & BIT(pll_info->enable_bit)))
 		ret = ingenic_pll_check_stable(cgu, pll_info);
 
 	spin_unlock_irqrestore(&cgu->lock, flags);
@@ -248,6 +251,9 @@ static int ingenic_pll_enable(struct clk_hw *hw)
 	int ret;
 	u32 ctl;
 
+	if (pll_info->enable_bit < 0)
+		return 0;
+
 	spin_lock_irqsave(&cgu->lock, flags);
 	if (pll_info->bypass_bit >= 0) {
 		ctl = readl(cgu->base + pll_info->bypass_reg);
@@ -278,6 +284,9 @@ static void ingenic_pll_disable(struct clk_hw *hw)
 	unsigned long flags;
 	u32 ctl;
 
+	if (pll_info->enable_bit < 0)
+		return;
+
 	spin_lock_irqsave(&cgu->lock, flags);
 	ctl = readl(cgu->base + pll_info->reg);
 
@@ -295,6 +304,9 @@ static int ingenic_pll_is_enabled(struct clk_hw *hw)
 	const struct ingenic_cgu_pll_info *pll_info = &clk_info->pll;
 	u32 ctl;
 
+	if (pll_info->enable_bit < 0)
+		return true;
+
 	ctl = readl(cgu->base + pll_info->reg);
 
 	return !!(ctl & BIT(pll_info->enable_bit));
diff --git a/drivers/clk/ingenic/cgu.h b/drivers/clk/ingenic/cgu.h
index 567142b584bb..a5e44ca7f969 100644
--- a/drivers/clk/ingenic/cgu.h
+++ b/drivers/clk/ingenic/cgu.h
@@ -42,8 +42,10 @@
  * @bypass_reg: the offset of the bypass control register within the CGU
  * @bypass_bit: the index of the bypass bit in the PLL control register, or
  *              -1 if there is no bypass bit
- * @enable_bit: the index of the enable bit in the PLL control register
- * @stable_bit: the index of the stable bit in the PLL control register
+ * @enable_bit: the index of the enable bit in the PLL control register, or
+ *		-1 if there is no enable bit (ie, the PLL is always on)
+ * @stable_bit: the index of the stable bit in the PLL control register, or
+ *		-1 if there is no stable bit
  */
 struct ingenic_cgu_pll_info {
 	unsigned reg;
@@ -54,8 +56,8 @@ struct ingenic_cgu_pll_info {
 	u8 od_shift, od_bits, od_max;
 	unsigned bypass_reg;
 	s8 bypass_bit;
-	u8 enable_bit;
-	u8 stable_bit;
+	s8 enable_bit;
+	s8 stable_bit;
 	void (*calc_m_n_od)(const struct ingenic_cgu_pll_info *pll_info,
 			    unsigned long rate, unsigned long parent_rate,
 			    unsigned int *m, unsigned int *n, unsigned int *od);
-- 
2.38.1