Message-Id: <a3bed3c2940edc238afbc191d595a727944892f3.1716965617.git.ysato@users.sourceforge.jp>
Date: Wed, 29 May 2024 17:01:00 +0900
From: Yoshinori Sato <ysato@...rs.sourceforge.jp>
To: linux-sh@...r.kernel.org
Cc: Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	Damien Le Moal <dlemoal@...nel.org>,
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Subject: [DO NOT MERGE v8 14/36] clk: Compatible with narrow registers

divider and gate only support 32-bit registers.
Older hardware uses narrower registers, so I want to be able to handle
8-bit and 16-bit wide registers.

Seven clk_divider flags are used, and if I add flags for 8bit access and
16bit access, 8bit will not be enough, so I expanded it to u16.

Signed-off-by: Yoshinori Sato <ysato@...rs.sourceforge.jp>
---
 drivers/clk/clk-divider.c    | 41 +++++++++++++++++++++---------
 drivers/clk/clk-gate.c       | 49 ++++++++++++++++++++++++++++++++----
 include/linux/clk-provider.h | 20 ++++++++++++---
 3 files changed, 89 insertions(+), 21 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index a2c2b5203b0a..abafcbbb6578 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -26,17 +26,34 @@
  * parent - fixed parent.  No clk_set_parent support
  */
 
-static inline u32 clk_div_readl(struct clk_divider *divider)
-{
+static inline u32 clk_div_read(struct clk_divider *divider)
+{
+	if (divider->flags & CLK_DIVIDER_REG_8BIT)
+		return readb(divider->reg);
+	if (divider->flags & CLK_DIVIDER_REG_16BIT) {
+		if (divider->flags & CLK_DIVIDER_BIG_ENDIAN) {
+			return ioread16be(divider->reg);
+		} else {
+			return readw(divider->reg);
+		}
+	}
 	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
 		return ioread32be(divider->reg);
 
 	return readl(divider->reg);
 }
 
-static inline void clk_div_writel(struct clk_divider *divider, u32 val)
+static inline void clk_div_write(struct clk_divider *divider, u32 val)
 {
-	if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+	if (divider->flags & CLK_DIVIDER_REG_8BIT)
+		writeb(val, divider->reg);
+	else if (divider->flags & CLK_DIVIDER_REG_16BIT) {
+		if (divider->flags & CLK_DIVIDER_BIG_ENDIAN) {
+			iowrite16be(val, divider->reg);
+		} else {
+			writew(val, divider->reg);
+		}
+	} else if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
 		iowrite32be(val, divider->reg);
 	else
 		writel(val, divider->reg);
@@ -152,7 +169,7 @@ static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 	struct clk_divider *divider = to_clk_divider(hw);
 	unsigned int val;
 
-	val = clk_div_readl(divider) >> divider->shift;
+	val = clk_div_read(divider) >> divider->shift;
 	val &= clk_div_mask(divider->width);
 
 	return divider_recalc_rate(hw, parent_rate, val, divider->table,
@@ -434,7 +451,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 		u32 val;
 
-		val = clk_div_readl(divider) >> divider->shift;
+		val = clk_div_read(divider) >> divider->shift;
 		val &= clk_div_mask(divider->width);
 
 		return divider_ro_round_rate(hw, rate, prate, divider->table,
@@ -455,7 +472,7 @@ static int clk_divider_determine_rate(struct clk_hw *hw,
 	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 		u32 val;
 
-		val = clk_div_readl(divider) >> divider->shift;
+		val = clk_div_read(divider) >> divider->shift;
 		val &= clk_div_mask(divider->width);
 
 		return divider_ro_determine_rate(hw, req, divider->table,
@@ -505,11 +522,11 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 	if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 		val = clk_div_mask(divider->width) << (divider->shift + 16);
 	} else {
-		val = clk_div_readl(divider);
+		val = clk_div_read(divider);
 		val &= ~(clk_div_mask(divider->width) << divider->shift);
 	}
 	val |= (u32)value << divider->shift;
-	clk_div_writel(divider, val);
+	clk_div_write(divider, val);
 
 	if (divider->lock)
 		spin_unlock_irqrestore(divider->lock, flags);
@@ -538,7 +555,7 @@ struct clk_hw *__clk_hw_register_divider(struct device *dev,
 		struct device_node *np, const char *name,
 		const char *parent_name, const struct clk_hw *parent_hw,
 		const struct clk_parent_data *parent_data, unsigned long flags,
-		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		void __iomem *reg, u8 shift, u8 width, u16 clk_divider_flags,
 		const struct clk_div_table *table, spinlock_t *lock)
 {
 	struct clk_divider *div;
@@ -610,7 +627,7 @@ EXPORT_SYMBOL_GPL(__clk_hw_register_divider);
 struct clk *clk_register_divider_table(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
-		u8 clk_divider_flags, const struct clk_div_table *table,
+		u16 clk_divider_flags, const struct clk_div_table *table,
 		spinlock_t *lock)
 {
 	struct clk_hw *hw;
@@ -664,7 +681,7 @@ struct clk_hw *__devm_clk_hw_register_divider(struct device *dev,
 		struct device_node *np, const char *name,
 		const char *parent_name, const struct clk_hw *parent_hw,
 		const struct clk_parent_data *parent_data, unsigned long flags,
-		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		void __iomem *reg, u8 shift, u8 width, u16 clk_divider_flags,
 		const struct clk_div_table *table, spinlock_t *lock)
 {
 	struct clk_hw **ptr, *hw;
diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
index 68e585a02fd9..22425568809e 100644
--- a/drivers/clk/clk-gate.c
+++ b/drivers/clk/clk-gate.c
@@ -24,16 +24,37 @@
  * parent - fixed parent.  No clk_set_parent support
  */
 
-static inline u32 clk_gate_readl(struct clk_gate *gate)
+static inline u32 clk_gate_read(struct clk_gate *gate)
 {
+	if (gate->flags & CLK_GATE_REG_8BIT)
+		return readb(gate->reg);
+	if (gate->flags & CLK_GATE_REG_16BIT) {
+		if (gate->flags & CLK_GATE_BIG_ENDIAN) {
+			return ioread16be(gate->reg);
+		} else {
+			return readw(gate->reg);
+		}
+	}
 	if (gate->flags & CLK_GATE_BIG_ENDIAN)
 		return ioread32be(gate->reg);
 
 	return readl(gate->reg);
 }
 
-static inline void clk_gate_writel(struct clk_gate *gate, u32 val)
+static inline void clk_gate_write(struct clk_gate *gate, u32 val)
 {
+	if (gate->flags & CLK_GATE_REG_8BIT) {
+		writeb(val, gate->reg);
+		return;
+	}
+	if (gate->flags & CLK_GATE_REG_16BIT) {
+		if (gate->flags & CLK_GATE_BIG_ENDIAN) {
+			iowrite16be(val, gate->reg);
+		} else {
+			writew(val, gate->reg);
+		}
+		return;
+	}
 	if (gate->flags & CLK_GATE_BIG_ENDIAN)
 		iowrite32be(val, gate->reg);
 	else
@@ -72,7 +93,7 @@ static void clk_gate_endisable(struct clk_hw *hw, int enable)
 		if (set)
 			reg |= BIT(gate->bit_idx);
 	} else {
-		reg = clk_gate_readl(gate);
+		reg = clk_gate_read(gate);
 
 		if (set)
 			reg |= BIT(gate->bit_idx);
@@ -80,7 +101,7 @@ static void clk_gate_endisable(struct clk_hw *hw, int enable)
 			reg &= ~BIT(gate->bit_idx);
 	}
 
-	clk_gate_writel(gate, reg);
+	clk_gate_write(gate, reg);
 
 	if (gate->lock)
 		spin_unlock_irqrestore(gate->lock, flags);
@@ -105,7 +126,7 @@ int clk_gate_is_enabled(struct clk_hw *hw)
 	u32 reg;
 	struct clk_gate *gate = to_clk_gate(hw);
 
-	reg = clk_gate_readl(gate);
+	reg = clk_gate_read(gate);
 
 	/* if a set bit disables this clk, flip it before masking */
 	if (gate->flags & CLK_GATE_SET_TO_DISABLE)
@@ -137,12 +158,30 @@ struct clk_hw *__clk_hw_register_gate(struct device *dev,
 	struct clk_init_data init = {};
 	int ret = -EINVAL;
 
+	/* validate register size option and bit_idx */
 	if (clk_gate_flags & CLK_GATE_HIWORD_MASK) {
 		if (bit_idx > 15) {
 			pr_err("gate bit exceeds LOWORD field\n");
 			return ERR_PTR(-EINVAL);
 		}
 	}
+	if (clk_gate_flags & CLK_GATE_REG_16BIT) {
+		if (bit_idx > 15) {
+			pr_err("gate bit exceeds 16 bits\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+	if (clk_gate_flags & CLK_GATE_REG_8BIT) {
+		if (bit_idx > 7) {
+			pr_err("gate bit exceeds 8 bits\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+	if ((clk_gate_flags & CLK_GATE_HIWORD_MASK) &&
+	    (clk_gate_flags & (CLK_GATE_REG_8BIT | CLK_GATE_REG_16BIT))) {
+		pr_err("HIWORD_MASK required 32-bit register\n");
+		return ERR_PTR(-EINVAL);
+	}
 
 	/* allocate the gate */
 	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 4a537260f655..25f61bd5b952 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -508,6 +508,10 @@ void of_fixed_clk_setup(struct device_node *np);
  * CLK_GATE_BIG_ENDIAN - by default little endian register accesses are used for
  *	the gate register.  Setting this flag makes the register accesses big
  *	endian.
+ * CLK_GATE_REG_8BIT - by default 32bit register accesses are used for
+ *	the gate register.  Setting this flag makes the register accesses 8bit.
+ * CLK_GATE_REG_16BIT - by default 32bit register accesses are used for
+ *	the gate register.  Setting this flag makes the register accesses 16bit.
  */
 struct clk_gate {
 	struct clk_hw hw;
@@ -522,6 +526,8 @@ struct clk_gate {
 #define CLK_GATE_SET_TO_DISABLE		BIT(0)
 #define CLK_GATE_HIWORD_MASK		BIT(1)
 #define CLK_GATE_BIG_ENDIAN		BIT(2)
+#define CLK_GATE_REG_8BIT		BIT(3)
+#define CLK_GATE_REG_16BIT		BIT(4)
 
 extern const struct clk_ops clk_gate_ops;
 struct clk_hw *__clk_hw_register_gate(struct device *dev,
@@ -675,13 +681,17 @@ struct clk_div_table {
  * CLK_DIVIDER_BIG_ENDIAN - By default little endian register accesses are used
  *	for the divider register.  Setting this flag makes the register accesses
  *	big endian.
+ * CLK_DIVIDER_REG_8BIT - by default 32bit register accesses are used for
+ *	the gate register.  Setting this flag makes the register accesses 8bit.
+ * CLK_DIVIDER_REG_16BIT - by default 32bit register accesses are used for
+ *	the gate register.  Setting this flag makes the register accesses 16bit.
  */
 struct clk_divider {
 	struct clk_hw	hw;
 	void __iomem	*reg;
 	u8		shift;
 	u8		width;
-	u8		flags;
+	u16		flags;
 	const struct clk_div_table	*table;
 	spinlock_t	*lock;
 };
@@ -697,6 +707,8 @@ struct clk_divider {
 #define CLK_DIVIDER_READ_ONLY		BIT(5)
 #define CLK_DIVIDER_MAX_AT_ZERO		BIT(6)
 #define CLK_DIVIDER_BIG_ENDIAN		BIT(7)
+#define CLK_DIVIDER_REG_8BIT		BIT(8)
+#define CLK_DIVIDER_REG_16BIT		BIT(9)
 
 extern const struct clk_ops clk_divider_ops;
 extern const struct clk_ops clk_divider_ro_ops;
@@ -726,18 +738,18 @@ struct clk_hw *__clk_hw_register_divider(struct device *dev,
 		struct device_node *np, const char *name,
 		const char *parent_name, const struct clk_hw *parent_hw,
 		const struct clk_parent_data *parent_data, unsigned long flags,
-		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		void __iomem *reg, u8 shift, u8 width, u16 clk_divider_flags,
 		const struct clk_div_table *table, spinlock_t *lock);
 struct clk_hw *__devm_clk_hw_register_divider(struct device *dev,
 		struct device_node *np, const char *name,
 		const char *parent_name, const struct clk_hw *parent_hw,
 		const struct clk_parent_data *parent_data, unsigned long flags,
-		void __iomem *reg, u8 shift, u8 width, u8 clk_divider_flags,
+		void __iomem *reg, u8 shift, u8 width, u16 clk_divider_flags,
 		const struct clk_div_table *table, spinlock_t *lock);
 struct clk *clk_register_divider_table(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
-		u8 clk_divider_flags, const struct clk_div_table *table,
+		u16 clk_divider_flags, const struct clk_div_table *table,
 		spinlock_t *lock);
 /**
  * clk_register_divider - register a divider clock with the clock framework
-- 
2.39.2

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