[PATCH v7 14/37] clk: Compatible with narrow registers

From: Yoshinori Sato
Date: Thu Apr 04 2024 - 01:03:32 EST

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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@xxxxxxxxxxxxxxxxxxxx>
---
drivers/clk/clk-divider.c | 56 +++++++++++++++++++++-----------
drivers/clk/clk-gate.c | 62 ++++++++++++++++++++++++++++--------
include/linux/clk-provider.h | 22 ++++++++++---
3 files changed, 103 insertions(+), 37 deletions(-)

diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index a2c2b5203b0a..a1b5187cd63d 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -26,20 +26,38 @@
* parent - fixed parent. No clk_set_parent support
*/

-static inline u32 clk_div_readl(struct clk_divider *divider)
-{
- if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
- return ioread32be(divider->reg);
-
- return readl(divider->reg);
+static inline u32 clk_div_read(struct clk_divider *divider)
+{
+ if (divider->flags & CLK_DIVIDER_REG_8BIT)
+ return readb(divider->reg);
+ else if (divider->flags & CLK_DIVIDER_REG_16BIT) {
+ if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+ return ioread16be(divider->reg);
+ else
+ return readw(divider->reg);
+ } else {
+ if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
+ return ioread32be(divider->reg);
+ else
+ 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)
- iowrite32be(val, divider->reg);
- else
- writel(val, divider->reg);
+ 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);
+ }
}

static unsigned int _get_table_maxdiv(const struct clk_div_table *table,
@@ -152,7 +170,7 @@ 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 +452,7 @@ 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 +473,7 @@ 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 +523,11 @@ 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 +556,7 @@ 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, u32 clk_divider_flags,
const struct clk_div_table *table, spinlock_t *lock)
{
struct clk_divider *div;
@@ -610,7 +628,7 @@ 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,
+ u32 clk_divider_flags, const struct clk_div_table *table,
spinlock_t *lock)
{
struct clk_hw *hw;
@@ -664,7 +682,7 @@ 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, u32 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..65191f9684ff 100644
--- a/drivers/clk/clk-gate.c
+++ b/drivers/clk/clk-gate.c
@@ -24,20 +24,38 @@
* 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_BIG_ENDIAN)
- return ioread32be(gate->reg);
-
- return readl(gate->reg);
+ if (gate->flags & CLK_GATE_REG_8BIT)
+ return readb(gate->reg);
+ else if (gate->flags & CLK_GATE_REG_16BIT) {
+ if (gate->flags & CLK_GATE_BIG_ENDIAN)
+ return ioread16be(gate->reg);
+ else
+ return readw(gate->reg);
+ } else {
+ if (gate->flags & CLK_GATE_BIG_ENDIAN)
+ return ioread32be(gate->reg);
+ else
+ 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_BIG_ENDIAN)
- iowrite32be(val, gate->reg);
- else
- writel(val, gate->reg);
+ if (gate->flags & CLK_GATE_REG_8BIT)
+ writeb(val, gate->reg);
+ else if (gate->flags & CLK_GATE_REG_16BIT) {
+ if (gate->flags & CLK_GATE_BIG_ENDIAN)
+ iowrite16be(val, gate->reg);
+ else
+ writew(val, gate->reg);
+ } else {
+ if (gate->flags & CLK_GATE_BIG_ENDIAN)
+ iowrite32be(val, gate->reg);
+ else
+ writel(val, gate->reg);
+ }
}

/*
@@ -72,7 +90,7 @@ 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 +98,7 @@ 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 +123,7 @@ 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 +155,30 @@ 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..eaa6ff1d0b2e 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -508,12 +508,16 @@ 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;
void __iomem *reg;
u8 bit_idx;
- u8 flags;
+ u32 flags;
spinlock_t *lock;
};

@@ -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, u32 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, u32 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,
+ u32 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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