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    Subject[PATCH v5 02/15] clk: at91: pmc: execute suspend/resume only for backup mode
    Date
    Before going to backup mode architecture specific PM code sets the first
    word in securam (file arch/arm/mach-at91/pm.c, function at91_pm_begin()).
    Thus take this into account when suspending/resuming clocks. This will
    avoid executing unnecessary instructions when suspending to non backup
    modes.

    Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
    ---
    drivers/clk/at91/pmc.c | 39 +++++++++++++++++++++++++++++++++++++++
    1 file changed, 39 insertions(+)

    diff --git a/drivers/clk/at91/pmc.c b/drivers/clk/at91/pmc.c
    index b2806946a77a..517973062719 100644
    --- a/drivers/clk/at91/pmc.c
    +++ b/drivers/clk/at91/pmc.c
    @@ -8,6 +8,7 @@
    #include <linux/clkdev.h>
    #include <linux/clk/at91_pmc.h>
    #include <linux/of.h>
    +#include <linux/of_address.h>
    #include <linux/mfd/syscon.h>
    #include <linux/platform_device.h>
    #include <linux/regmap.h>
    @@ -110,13 +111,35 @@ struct pmc_data *pmc_data_allocate(unsigned int ncore, unsigned int nsystem,
    }

    #ifdef CONFIG_PM
    +
    +/* Address in SECURAM that say if we suspend to backup mode. */
    +static void __iomem *at91_pmc_backup_suspend;
    +
    static int at91_pmc_suspend(void)
    {
    + unsigned int backup;
    +
    + if (!at91_pmc_backup_suspend)
    + return 0;
    +
    + backup = readl_relaxed(at91_pmc_backup_suspend);
    + if (!backup)
    + return 0;
    +
    return clk_save_context();
    }

    static void at91_pmc_resume(void)
    {
    + unsigned int backup;
    +
    + if (!at91_pmc_backup_suspend)
    + return;
    +
    + backup = readl_relaxed(at91_pmc_backup_suspend);
    + if (!backup)
    + return;
    +
    clk_restore_context();
    }

    @@ -144,6 +167,22 @@ static int __init pmc_register_ops(void)
    }
    of_node_put(np);

    + np = of_find_compatible_node(NULL, NULL, "atmel,sama5d2-securam");
    + if (!np)
    + return -ENODEV;
    +
    + if (!of_device_is_available(np)) {
    + of_node_put(np);
    + return -ENODEV;
    + }
    + of_node_put(np);
    +
    + at91_pmc_backup_suspend = of_iomap(np, 0);
    + if (!at91_pmc_backup_suspend) {
    + pr_warn("%s(): unable to map securam\n", __func__);
    + return -ENOMEM;
    + }
    +
    register_syscore_ops(&pmc_syscore_ops);

    return 0;
    --
    2.25.1
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