At least one user currently duplicates some functions that are provided
by fractional divider module. Let's export approximation algo and replace
the open-coded variant.
As a bonus the exported function will get better documentation in place.
Signed-off-by: Andy Shevchenko <[email protected]>
---
v2: fixed compilation error (LKP), successfully compile-tested on x86
drivers/clk/clk-fractional-divider.c | 11 +++++++----
drivers/clk/clk-fractional-divider.h | 9 +++++++++
drivers/clk/rockchip/clk.c | 17 +++--------------
3 files changed, 19 insertions(+), 18 deletions(-)
create mode 100644 drivers/clk/clk-fractional-divider.h
diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
index b1e556f20911..535d299af646 100644
--- a/drivers/clk/clk-fractional-divider.c
+++ b/drivers/clk/clk-fractional-divider.c
@@ -14,6 +14,8 @@
#include <linux/slab.h>
#include <linux/rational.h>
+#include "clk-fractional-divider.h"
+
static inline u32 clk_fd_readl(struct clk_fractional_divider *fd)
{
if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN)
@@ -68,9 +70,10 @@ static unsigned long clk_fd_recalc_rate(struct clk_hw *hw,
return ret;
}
-static void clk_fd_general_approximation(struct clk_hw *hw, unsigned long rate,
- unsigned long *parent_rate,
- unsigned long *m, unsigned long *n)
+void clk_fractional_divider_general_approximation(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long *parent_rate,
+ unsigned long *m, unsigned long *n)
{
struct clk_fractional_divider *fd = to_clk_fd(hw);
unsigned long scale;
@@ -102,7 +105,7 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate,
if (fd->approximation)
fd->approximation(hw, rate, parent_rate, &m, &n);
else
- clk_fd_general_approximation(hw, rate, parent_rate, &m, &n);
+ clk_fractional_divider_general_approximation(hw, rate, parent_rate, &m, &n);
ret = (u64)*parent_rate * m;
do_div(ret, n);
diff --git a/drivers/clk/clk-fractional-divider.h b/drivers/clk/clk-fractional-divider.h
new file mode 100644
index 000000000000..4fa359a12ef4
--- /dev/null
+++ b/drivers/clk/clk-fractional-divider.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+struct clk_hw;
+
+void clk_fractional_divider_general_approximation(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long *parent_rate,
+ unsigned long *m,
+ unsigned long *n);
diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
index 049e5e0b64f6..b7be7e11b0df 100644
--- a/drivers/clk/rockchip/clk.c
+++ b/drivers/clk/rockchip/clk.c
@@ -22,6 +22,8 @@
#include <linux/regmap.h>
#include <linux/reboot.h>
#include <linux/rational.h>
+
+#include "../clk-fractional-divider.h"
#include "clk.h"
/*
@@ -178,10 +180,8 @@ static void rockchip_fractional_approximation(struct clk_hw *hw,
unsigned long rate, unsigned long *parent_rate,
unsigned long *m, unsigned long *n)
{
- struct clk_fractional_divider *fd = to_clk_fd(hw);
unsigned long p_rate, p_parent_rate;
struct clk_hw *p_parent;
- unsigned long scale;
p_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
if ((rate * 20 > p_rate) && (p_rate % rate != 0)) {
@@ -190,18 +190,7 @@ static void rockchip_fractional_approximation(struct clk_hw *hw,
*parent_rate = p_parent_rate;
}
- /*
- * Get rate closer to *parent_rate to guarantee there is no overflow
- * for m and n. In the result it will be the nearest rate left shifted
- * by (scale - fd->nwidth) bits.
- */
- scale = fls_long(*parent_rate / rate - 1);
- if (scale > fd->nwidth)
- rate <<= scale - fd->nwidth;
-
- rational_best_approximation(rate, *parent_rate,
- GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0),
- m, n);
+ clk_fractional_divider_general_approximation(hw, rate, parent_rate, m, n);
}
static struct clk *rockchip_clk_register_frac_branch(
--
2.30.2
Am Freitag, 16. Juli 2021, 15:34:46 CEST schrieb Andy Shevchenko:
> At least one user currently duplicates some functions that are provided
> by fractional divider module. Let's export approximation algo and replace
> the open-coded variant.
>
> As a bonus the exported function will get better documentation in place.
>
> Signed-off-by: Andy Shevchenko <[email protected]>
on Rockchip rk3288 and rk3399
Tested-by: Heiko Stuebner <[email protected]>
Also for dropping the Rockchip-specific copy in favor of the main
implementation
Acked-by: Heiko Stuebner <[email protected]>
> ---
> v2: fixed compilation error (LKP), successfully compile-tested on x86
> drivers/clk/clk-fractional-divider.c | 11 +++++++----
> drivers/clk/clk-fractional-divider.h | 9 +++++++++
> drivers/clk/rockchip/clk.c | 17 +++--------------
> 3 files changed, 19 insertions(+), 18 deletions(-)
> create mode 100644 drivers/clk/clk-fractional-divider.h
>
> diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
> index b1e556f20911..535d299af646 100644
> --- a/drivers/clk/clk-fractional-divider.c
> +++ b/drivers/clk/clk-fractional-divider.c
> @@ -14,6 +14,8 @@
> #include <linux/slab.h>
> #include <linux/rational.h>
>
> +#include "clk-fractional-divider.h"
> +
> static inline u32 clk_fd_readl(struct clk_fractional_divider *fd)
> {
> if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN)
> @@ -68,9 +70,10 @@ static unsigned long clk_fd_recalc_rate(struct clk_hw *hw,
> return ret;
> }
>
> -static void clk_fd_general_approximation(struct clk_hw *hw, unsigned long rate,
> - unsigned long *parent_rate,
> - unsigned long *m, unsigned long *n)
> +void clk_fractional_divider_general_approximation(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *parent_rate,
> + unsigned long *m, unsigned long *n)
> {
> struct clk_fractional_divider *fd = to_clk_fd(hw);
> unsigned long scale;
> @@ -102,7 +105,7 @@ static long clk_fd_round_rate(struct clk_hw *hw, unsigned long rate,
> if (fd->approximation)
> fd->approximation(hw, rate, parent_rate, &m, &n);
> else
> - clk_fd_general_approximation(hw, rate, parent_rate, &m, &n);
> + clk_fractional_divider_general_approximation(hw, rate, parent_rate, &m, &n);
>
> ret = (u64)*parent_rate * m;
> do_div(ret, n);
> diff --git a/drivers/clk/clk-fractional-divider.h b/drivers/clk/clk-fractional-divider.h
> new file mode 100644
> index 000000000000..4fa359a12ef4
> --- /dev/null
> +++ b/drivers/clk/clk-fractional-divider.h
> @@ -0,0 +1,9 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +struct clk_hw;
> +
> +void clk_fractional_divider_general_approximation(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *parent_rate,
> + unsigned long *m,
> + unsigned long *n);
> diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
> index 049e5e0b64f6..b7be7e11b0df 100644
> --- a/drivers/clk/rockchip/clk.c
> +++ b/drivers/clk/rockchip/clk.c
> @@ -22,6 +22,8 @@
> #include <linux/regmap.h>
> #include <linux/reboot.h>
> #include <linux/rational.h>
> +
> +#include "../clk-fractional-divider.h"
> #include "clk.h"
>
> /*
> @@ -178,10 +180,8 @@ static void rockchip_fractional_approximation(struct clk_hw *hw,
> unsigned long rate, unsigned long *parent_rate,
> unsigned long *m, unsigned long *n)
> {
> - struct clk_fractional_divider *fd = to_clk_fd(hw);
> unsigned long p_rate, p_parent_rate;
> struct clk_hw *p_parent;
> - unsigned long scale;
>
> p_rate = clk_hw_get_rate(clk_hw_get_parent(hw));
> if ((rate * 20 > p_rate) && (p_rate % rate != 0)) {
> @@ -190,18 +190,7 @@ static void rockchip_fractional_approximation(struct clk_hw *hw,
> *parent_rate = p_parent_rate;
> }
>
> - /*
> - * Get rate closer to *parent_rate to guarantee there is no overflow
> - * for m and n. In the result it will be the nearest rate left shifted
> - * by (scale - fd->nwidth) bits.
> - */
> - scale = fls_long(*parent_rate / rate - 1);
> - if (scale > fd->nwidth)
> - rate <<= scale - fd->nwidth;
> -
> - rational_best_approximation(rate, *parent_rate,
> - GENMASK(fd->mwidth - 1, 0), GENMASK(fd->nwidth - 1, 0),
> - m, n);
> + clk_fractional_divider_general_approximation(hw, rate, parent_rate, m, n);
> }
>
> static struct clk *rockchip_clk_register_frac_branch(
>