On Thu, May 28, 2015 at 8:53 PM, Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> Add Clock Domain support to the Clock Pulse Generator (CPG) Module Stop
> (MSTP) Clocks driver using the generic PM Domain. This allows to
> power-manage the module clocks of SoC devices that are part of the CPG
> Clock Domain using Runtime PM, or for system suspend/resume.
>
> SoC devices that are part of a CPG Clock Domain and can be
> power-managed through an MSTP clock should be tagged in DT with a
> proper "power-domains" property.
>
> The CPG Clock Domain code will scan such devices for clocks that are
> suitable for power-managing the device, by looking for a clock that is
> compatible with "renesas,cpg-mstp-clocks".
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Reviewed-by: Kevin Hilman <khilman@xxxxxxxxxx>
> ---
> v2:
> - Add Acked-by and Reviewed-by,
> - Move core CPG Clock Domain code from the R-Car Gen2 driver to the
> CPG MSTP Clocks driver, as it's generic, and can be used on other
> Renesas SoCs that have a CPG/MSTP block,
> - Scan for an MSTP clock instead of using the first clock tied to the
> device (con_id NULL),
> - Extract R-Car Gen2 specifics to a separate patch.
> ---
> drivers/clk/shmobile/clk-mstp.c | 86 ++++++++++++++++++++++++++++++++++++
> drivers/clk/shmobile/clk-rcar-gen2.c | 2 +
> include/linux/clk/shmobile.h | 12 +++++
> 3 files changed, 100 insertions(+)
>
> diff --git a/drivers/clk/shmobile/clk-mstp.c b/drivers/clk/shmobile/clk-mstp.c
> index 2d2fe773ac8168f9..619f3eccefd4884f 100644
> --- a/drivers/clk/shmobile/clk-mstp.c
> +++ b/drivers/clk/shmobile/clk-mstp.c
> @@ -236,3 +241,84 @@ static void __init cpg_mstp_clocks_init(struct device_node *np)
> of_clk_add_provider(np, of_clk_src_onecell_get, &group->data);
> }
> CLK_OF_DECLARE(cpg_mstp_clks, "renesas,cpg-mstp-clocks", cpg_mstp_clocks_init);
> +
> +
> +#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> +int cpg_mstp_attach_dev(struct generic_pm_domain *domain, struct device *dev)
> +{
> + struct device_node *np = dev->of_node;
> + struct of_phandle_args clkspec;
> + struct clk *clk;
> + int i = 0;
> + int error;
> +
> + while (!of_parse_phandle_with_args(np, "clocks", "#clock-cells", i,
> + &clkspec)) {
> + if (of_device_is_compatible(clkspec.np,
> + "renesas,cpg-mstp-clocks"))
> + goto found;
> +
> + of_node_put(clkspec.np);
> + i++;
> + }
> +
> + return 0;
> +
> +found:
> + clk = of_clk_get_from_provider(&clkspec);
> + of_node_put(clkspec.np);
> +
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + error = pm_clk_create(dev);
> + if (error) {
> + dev_err(dev, "pm_clk_create failed %d\n", error);
> + goto fail_put;
> + }
> +
> + error = pm_clk_add_clk(dev, clk);
> + if (error) {
> + dev_err(dev, "pm_clk_add_clk %pC failed %d\n", clk, error);
> + goto fail_destroy;
> + }
> +
> + return 0;
> +
> +fail_destroy:
> + pm_clk_destroy(dev);
> +fail_put:
> + clk_put(clk);
> + return error;
> +}
> +
> +void cpg_mstp_detach_dev(struct generic_pm_domain *domain, struct device *dev)
> +{
> + pm_clk_destroy(dev);
This should only be done if cpg_mstp_attach_dev() actually added a clock, i.e.
if (!list_empty(&dev->power.subsys_data->clock_list))
pm_clk_destroy(dev);
Else it will free the subsys_data allocated by genpd_alloc_dev_data()
prematurely, and genpd_free_dev_data() will crash when dereferencing
dev->power.subsys_data.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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