linux-kernel - Re: [RFC PATCH v3 2/2] clk: exynos5420: Make sure MDMA0 clock is enabled during suspend

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Date:	Tue, 31 Mar 2015 01:07:41 +0900
From:	Tomasz Figa <tomasz.figa@...il.com>
To:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Cc:	Stephen Boyd <sboyd@...eaurora.org>,
	Mike Turquette <mturquette@...aro.org>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Kukjin Kim <kgene@...nel.org>, Olof Johansson <olof@...om.net>,
	Doug Anderson <dianders@...omium.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Kevin Hilman <khilman@...aro.org>,
	Tyler Baker <tyler.baker@...aro.org>,
	Abhilash Kesavan <kesavan.abhilash@...il.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH v3 2/2] clk: exynos5420: Make sure MDMA0 clock is
 enabled during suspend

Hi Javier,

Please see my comments inline.

2015-03-31 0:53 GMT+09:00 Javier Martinez Canillas
<javier.martinez@...labora.co.uk>:
[snip]
> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
> index 07d666cc6a29..2d39b629144a 100644
> --- a/drivers/clk/samsung/clk-exynos5420.c
> +++ b/drivers/clk/samsung/clk-exynos5420.c
> @@ -151,6 +151,7 @@ enum exynos5x_plls {
>
>  static void __iomem *reg_base;
>  static enum exynos5x_soc exynos5x_soc;
> +struct samsung_clk_provider *ctx;

static

>
>  #ifdef CONFIG_PM_SLEEP
>  static struct samsung_clk_reg_dump *exynos5x_save;
> @@ -275,8 +276,18 @@ static const struct samsung_clk_reg_dump exynos5420_set_clksrc[] = {
>         { .offset = GATE_IP_PERIC,              .value = 0xffffffff, },
>  };
>
> +/*
> + * list of clocks that have to be kept enabled during suspend/resume cycle.
> + */
> +static unsigned int exynos5x_clk_suspend[] = {

static const

> +       CLK_MDMA0,
> +};
> +
>  static int exynos5420_clk_suspend(void)
>  {
> +       int i;
> +       struct clk *clk;
> +
>         samsung_clk_save(reg_base, exynos5x_save,
>                                 ARRAY_SIZE(exynos5x_clk_regs));
>
> @@ -287,11 +298,24 @@ static int exynos5420_clk_suspend(void)
>         samsung_clk_restore(reg_base, exynos5420_set_clksrc,
>                                 ARRAY_SIZE(exynos5420_set_clksrc));
>
> +       for (i = 0; i < ARRAY_SIZE(exynos5x_clk_suspend); i++) {
> +               clk = samsung_clk_lookup(ctx, exynos5x_clk_suspend[i]);

If look-up speed is important here, maybe all the relevant clocks
could be looked up once at initialization time and just prepared and
enabled here?

Best regards,
Tomasz
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