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Message-Id: <20241004-mbly-clk-v4-3-c72c2e348e1f@bootlin.com>
Date: Fri, 04 Oct 2024 17:45:35 +0200
From: Théo Lebrun <theo.lebrun@...tlin.com>
To: Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>
Cc: devicetree@...r.kernel.org, linux-clk@...r.kernel.org,
linux-kernel@...r.kernel.org,
Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>,
Grégory Clement <gregory.clement@...tlin.com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Tawfik Bayouk <tawfik.bayouk@...ileye.com>,
Théo Lebrun <theo.lebrun@...tlin.com>
Subject: [PATCH v4 3/4] clk: divider: Introduce CLK_DIVIDER_EVEN_INTEGERS
flag
Add CLK_DIVIDER_EVEN_INTEGERS flag to support divisor of 2, 4, 6, etc.
The same divisor can be done using a table, which would be big and
wasteful for a clock dividor of width 8 (256 entries).
Require increasing flags size from u8 to u16 because
CLK_DIVIDER_EVEN_INTEGERS is the eighth flag. u16 is used inside struct
clk_divider; `unsigned long` is used for function arguments.
Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
---
drivers/clk/clk-divider.c | 16 ++++++++++++----
include/linux/clk-provider.h | 15 ++++++++++-----
2 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index a2c2b5203b0a95cf1cf651b1fb4e2c24d230d831..c1f426b8a5043cb5a1de08e1da385928ec54a2ed 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -72,6 +72,8 @@ static unsigned int _get_maxdiv(const struct clk_div_table *table, u8 width,
return clk_div_mask(width);
if (flags & CLK_DIVIDER_POWER_OF_TWO)
return 1 << clk_div_mask(width);
+ if (flags & CLK_DIVIDER_EVEN_INTEGERS)
+ return 2 * (clk_div_mask(width) + 1);
if (table)
return _get_table_maxdiv(table, width);
return clk_div_mask(width) + 1;
@@ -97,6 +99,8 @@ static unsigned int _get_div(const struct clk_div_table *table,
return 1 << val;
if (flags & CLK_DIVIDER_MAX_AT_ZERO)
return val ? val : clk_div_mask(width) + 1;
+ if (flags & CLK_DIVIDER_EVEN_INTEGERS)
+ return 2 * (val + 1);
if (table)
return _get_table_div(table, val);
return val + 1;
@@ -122,6 +126,8 @@ static unsigned int _get_val(const struct clk_div_table *table,
return __ffs(div);
if (flags & CLK_DIVIDER_MAX_AT_ZERO)
return (div == clk_div_mask(width) + 1) ? 0 : div;
+ if (flags & CLK_DIVIDER_EVEN_INTEGERS)
+ return (div >> 1) - 1;
if (table)
return _get_table_val(table, div);
return div - 1;
@@ -538,7 +544,8 @@ 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,
+ unsigned long clk_divider_flags,
const struct clk_div_table *table, spinlock_t *lock)
{
struct clk_divider *div;
@@ -610,8 +617,8 @@ 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,
- spinlock_t *lock)
+ unsigned long clk_divider_flags,
+ const struct clk_div_table *table, spinlock_t *lock)
{
struct clk_hw *hw;
@@ -664,7 +671,8 @@ 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,
+ unsigned long clk_divider_flags,
const struct clk_div_table *table, spinlock_t *lock)
{
struct clk_hw **ptr, *hw;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7e43caabb54b901d68484b86c8349febfe12ba0f..dbe793964c24ca3ab3a7facd090dfb6ae9df7631 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -689,13 +689,15 @@ 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_EVEN_INTEGERS - clock divisor is 2, 4, 6, 8, 10, etc.
+ * Formula is 2 * (value read from hardware + 1).
*/
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;
};
@@ -711,6 +713,7 @@ 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_EVEN_INTEGERS BIT(8)
extern const struct clk_ops clk_divider_ops;
extern const struct clk_ops clk_divider_ro_ops;
@@ -740,19 +743,21 @@ 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,
+ unsigned long 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,
+ unsigned long 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,
- spinlock_t *lock);
+ unsigned long clk_divider_flags,
+ const struct clk_div_table *table, spinlock_t *lock);
/**
* clk_register_divider - register a divider clock with the clock framework
* @dev: device registering this clock
--
2.46.2
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