Re: [PATCH v2 5/7] clk: exynos: use cpu-clock provider type to represent arm clock

Lukasz Majewski
2014-01-20T07:47:21Z

Hi Thomas,

> From: Thomas Abraham <thomas.ab@samsung.com>
>
> With the addition of the new Samsung specific cpu-clock type, the
> arm clock can be represented as a cpu-clock type and the independent
> clock blocks that made up the arm clock can be removed.
>
> Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
> ---
> .../devicetree/bindings/clock/exynos5250-clock.txt | 1 +
> drivers/clk/samsung/clk-exynos4.c | 11 +++++------
> drivers/clk/samsung/clk-exynos5250.c | 8 ++++----
> include/dt-bindings/clock/exynos5250.h | 1 +
> 4 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git
> a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt
> b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt index
> 99eae9c..acf867a 100644 ---
> a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt +++
> b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt @@
> -38,6 +38,7 @@ clock which they consume. ----------------------------
> fin_pll 1
> + armclk 12
>
> [Clock Gate for Special Clocks]
>
> diff --git a/drivers/clk/samsung/clk-exynos4.c
> b/drivers/clk/samsung/clk-exynos4.c index 010f071..efcf4a3 100644
> --- a/drivers/clk/samsung/clk-exynos4.c
> +++ b/drivers/clk/samsung/clk-exynos4.c
> @@ -437,8 +437,6 @@ static struct samsung_mux_clock
> exynos4x12_mux_clks[] __initdata = {
> /* list of divider clocks supported in all exynos4 soc's */
> static struct samsung_div_clock exynos4_div_clks[] __initdata = {
> - DIV(0, "div_core", "mout_core", DIV_CPU0, 0, 3),
> - DIV(0, "div_core2", "div_core", DIV_CPU0, 28, 3),
> DIV(0, "div_fimc0", "mout_fimc0", DIV_CAM, 0, 4),
> DIV(0, "div_fimc1", "mout_fimc1", DIV_CAM, 4, 4),
> DIV(0, "div_fimc2", "mout_fimc2", DIV_CAM, 8, 4),
> @@ -484,8 +482,8 @@ static struct samsung_div_clock
> exynos4_div_clks[] __initdata = { DIV(0, "div_spi_pre2", "div_spi2",
> DIV_PERIL2, 8, 8), DIV(0, "div_audio1", "mout_audio1", DIV_PERIL4, 0,
> 4), DIV(0, "div_audio2", "mout_audio2", DIV_PERIL4, 16, 4),
> - DIV(CLK_ARM_CLK, "arm_clk", "div_core2", DIV_CPU0, 28, 3),
> - DIV(CLK_SCLK_APLL, "sclk_apll", "mout_apll", DIV_CPU0, 24,
> 3),
> + DIV_F(CLK_SCLK_APLL, "sclk_apll", "mout_apll", DIV_CPU0, 24,
> 3,
> + CLK_GET_RATE_NOCACHE, 0),
> DIV_F(0, "div_mipi_pre0", "div_mipi0", DIV_LCD0, 20, 4,
> CLK_SET_RATE_PARENT, 0),
> DIV_F(0, "div_mmc_pre0", "div_mmc0", DIV_FSYS1, 8, 8,
> @@ -870,7 +868,6 @@ static struct samsung_gate_clock
> exynos4x12_gate_clks[] __initdata = {
> static struct samsung_clock_alias exynos4_aliases[] __initdata = {
> ALIAS(CLK_MOUT_CORE, NULL, "moutcore"),
> - ALIAS(CLK_ARM_CLK, NULL, "armclk"),
> ALIAS(CLK_SCLK_APLL, NULL, "mout_apll"),
> };
>
> @@ -1125,12 +1122,14 @@ static void __init exynos4_clk_init(struct
> device_node *np, samsung_clk_register_alias(exynos4_aliases,
> ARRAY_SIZE(exynos4_aliases));
>
> + samsung_register_arm_clock(np, CLK_ARM_CLK, "mout_apll",
> reg_base); +

I've got some doubts about allowing only the "mout_apll" clock to be the
only parent for armclk Samsung clock.

For the Exynos4412 it is also valid to have SCLK_MPLL_USER_C [*] as a
parent for this clock.

The problem is that you are reparenting the armclk to [*] with the
register modification - no CCF involved.

I just would like to know if this is yours design decision or
something, that we have overlooked in the v1 of this patch series.

> pr_info("%s clocks: sclk_apll = %ld, sclk_mpll = %ld\n"
> "\tsclk_epll = %ld, sclk_vpll = %ld, arm_clk =
> %ld\n", exynos4_soc == EXYNOS4210 ? "Exynos4210" : "Exynos4x12",
> _get_rate("sclk_apll"),
> _get_rate("sclk_mpll"), _get_rate("sclk_epll"),
> _get_rate("sclk_vpll"),
> - _get_rate("arm_clk"));
> + _get_rate("armclk"));
> }
>
>
> diff --git a/drivers/clk/samsung/clk-exynos5250.c
> b/drivers/clk/samsung/clk-exynos5250.c index ff4beeb..487be36 100644
> --- a/drivers/clk/samsung/clk-exynos5250.c
> +++ b/drivers/clk/samsung/clk-exynos5250.c
> @@ -298,9 +298,8 @@ static struct samsung_div_clock
> exynos5250_div_clks[] __initdata = { /*
> * CMU_CPU
> */
> - DIV(0, "div_arm", "mout_cpu", DIV_CPU0, 0, 3),
> - DIV(0, "div_apll", "mout_apll", DIV_CPU0, 24, 3),
> - DIV_A(0, "div_arm2", "div_arm", DIV_CPU0, 28, 3, "armclk"),
> + DIV_F(0, "div_apll", "mout_apll", DIV_CPU0, 24, 3,
> + CLK_GET_RATE_NOCACHE, 0),
>
> /*
> * CMU_TOP
> @@ -684,8 +683,9 @@ static void __init exynos5250_clk_init(struct
> device_node *np) ARRAY_SIZE(exynos5250_div_clks));
> samsung_clk_register_gate(exynos5250_gate_clks,
> ARRAY_SIZE(exynos5250_gate_clks));
> + samsung_register_arm_clock(np, CLK_ARM_CLK, "mout_apll",
> reg_base);
> pr_info("Exynos5250: clock setup completed, armclk=%ld\n",
> - _get_rate("div_arm2"));
> + _get_rate("armclk"));
> }
> CLK_OF_DECLARE(exynos5250_clk, "samsung,exynos5250-clock",
> exynos5250_clk_init); diff --git
> a/include/dt-bindings/clock/exynos5250.h
> b/include/dt-bindings/clock/exynos5250.h index 922f2dc..59a10fb
> 100644 --- a/include/dt-bindings/clock/exynos5250.h +++
> b/include/dt-bindings/clock/exynos5250.h @@ -21,6 +21,7 @@
> #define CLK_FOUT_CPLL 6
> #define CLK_FOUT_EPLL 7
> #define CLK_FOUT_VPLL 8
> +#define CLK_ARM_CLK 12
>
> /* gate for special clocks (sclk) */
> #define CLK_SCLK_CAM_BAYER 128

--
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group