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Message-ID: <CAJZ5v0iEo=jj+T-0bQypxs8VTb7kPpczSRu+8-+F7oyRMk9nSA@mail.gmail.com>
Date: Wed, 9 Mar 2016 15:04:56 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Jon Hunter <jonathanh@...dia.com>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-tegra@...r.kernel.org
Subject: Re: [PATCH V2] PM / clk: Add support for obtaining clocks from device-tree
On Wed, Mar 9, 2016 at 2:13 PM, Jon Hunter <jonathanh@...dia.com> wrote:
> The PM clocks framework requires clients to pass either a con-id or a
> valid clk pointer in order to add a clock to a device. Add a new
> function of_pm_clk_add_clks() to allows device clocks to be retrieved
> from device-tree and populated for a given device. Note that
> of_clk_get_from_provider() is not defined if CONFIG_OF and
> CONFIG_COMMON_CLK are not selected. Therefore, make of_pm_clk_add_clks()
> dependent on these options.
>
> An optional function pointer may be passed to of_pm_clk_add_clks() that
> can be used to filter the clocks that are added for a device when
> calling of_pm_clk_add_clks().
>
> In order to handle errors encountered when adding clocks from
> device-tree, add a function pm_clk_remove_clk() to remove any clocks
> (using a pointer to the clk structure) that have been added
> successfully before the error occurred.
>
> Signed-off-by: Jon Hunter <jonathanh@...dia.com>
> ---
>
> Changes v1-v2:
> - Added support for optional filter function as suggested by Geert U.
I'd like to get an ACK on this from someone more familiar with the DT
stuff than I am.
Thanks,
Rafael
> drivers/base/power/clock_ops.c | 109 +++++++++++++++++++++++++++++++++++++++++
> include/linux/pm_clock.h | 16 ++++++
> 2 files changed, 125 insertions(+)
>
> diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c
> index 272a52ebafc0..0c2213145b4a 100644
> --- a/drivers/base/power/clock_ops.c
> +++ b/drivers/base/power/clock_ops.c
> @@ -137,6 +137,82 @@ int pm_clk_add_clk(struct device *dev, struct clk *clk)
> return __pm_clk_add(dev, NULL, clk);
> }
>
> +
> +#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
> +/**
> + * of_pm_clk_add_clks - Start using device clock(s) for power management.
> + * @dev: Device whose clock(s) is going to be used for power management.
> + * @of_pm_clk_filter: Optional function for filtering clocks
> + *
> + * Add a series of clocks described in the 'clocks' device-tree node for
> + * a device to the list of clocks used for the power management of @dev.
> + * If 'of_pm_clk_filter' is specified, then this filter function will be
> + * called for each clock found and the clock will be added to the list
> + * of clocks if this function returns true. Return success if clocks are
> + * added successfully and return a negative error code if adding a clock
> + * fails or there are no clocks that match with the filter function.
> + */
> +int of_pm_clk_add_clks(struct device *dev,
> + bool (*of_pm_clk_filter)(struct of_phandle_args *args))
> +{
> + struct of_phandle_args clkspec;
> + struct clk **clks;
> + unsigned int i, count, added = 0;
> + int ret;
> +
> + if (!dev || !dev->of_node)
> + return -EINVAL;
> +
> + count = of_count_phandle_with_args(dev->of_node, "clocks",
> + "#clock-cells");
> + if (count == 0)
> + return -ENODEV;
> +
> + clks = kcalloc(count, sizeof(*clks), GFP_KERNEL);
> + if (!clks)
> + return -ENOMEM;
> +
> + for (i = 0; i < count; i++) {
> + if (of_parse_phandle_with_args(dev->of_node, "clocks",
> + "#clock-cells", i, &clkspec))
> + goto error;
> +
> + if (of_pm_clk_filter && !of_pm_clk_filter(&clkspec)) {
> + of_node_put(clkspec.np);
> + continue;
> + }
> +
> + clks[added] = of_clk_get_from_provider(&clkspec);
> + of_node_put(clkspec.np);
> +
> + if (IS_ERR(clks[added])) {
> + ret = PTR_ERR(clks[added]);
> + goto error;
> + }
> +
> + ret = pm_clk_add_clk(dev, clks[added]);
> + if (ret) {
> + clk_put(clks[added]);
> + goto error;
> + }
> +
> + added++;
> + }
> +
> + kfree(clks);
> +
> + return added ? 0 : -ENODEV;
> +
> +error:
> + while (added--)
> + pm_clk_remove_clk(dev, clks[added]);
> +
> + kfree(clks);
> +
> + return ret;
> +}
> +#endif /* CONFIG_OF && CONFIG_COMMON_CLK */
> +
> /**
> * __pm_clk_remove - Destroy PM clock entry.
> * @ce: PM clock entry to destroy.
> @@ -198,6 +274,39 @@ void pm_clk_remove(struct device *dev, const char *con_id)
> }
>
> /**
> + * pm_clk_remove_clk - Stop using a device clock for power management.
> + * @dev: Device whose clock should not be used for PM any more.
> + * @clk: Clock pointer
> + *
> + * Remove the clock pointed to by @clk from the list of clocks used for
> + * the power management of @dev.
> + */
> +void pm_clk_remove_clk(struct device *dev, struct clk *clk)
> +{
> + struct pm_subsys_data *psd = dev_to_psd(dev);
> + struct pm_clock_entry *ce;
> +
> + if (!psd || !clk)
> + return;
> +
> + spin_lock_irq(&psd->lock);
> +
> + list_for_each_entry(ce, &psd->clock_list, node) {
> + if (clk == ce->clk)
> + goto remove;
> + }
> +
> + spin_unlock_irq(&psd->lock);
> + return;
> +
> + remove:
> + list_del(&ce->node);
> + spin_unlock_irq(&psd->lock);
> +
> + __pm_clk_remove(ce);
> +}
> +
> +/**
> * pm_clk_init - Initialize a device's list of power management clocks.
> * @dev: Device to initialize the list of PM clocks for.
> *
> diff --git a/include/linux/pm_clock.h b/include/linux/pm_clock.h
> index 25266c600021..3aa5ad57067a 100644
> --- a/include/linux/pm_clock.h
> +++ b/include/linux/pm_clock.h
> @@ -11,6 +11,7 @@
>
> #include <linux/device.h>
> #include <linux/notifier.h>
> +#include <linux/of.h>
>
> struct pm_clk_notifier_block {
> struct notifier_block nb;
> @@ -43,6 +44,7 @@ extern void pm_clk_destroy(struct device *dev);
> extern int pm_clk_add(struct device *dev, const char *con_id);
> extern int pm_clk_add_clk(struct device *dev, struct clk *clk);
> extern void pm_clk_remove(struct device *dev, const char *con_id);
> +extern void pm_clk_remove_clk(struct device *dev, struct clk *clk);
> extern int pm_clk_suspend(struct device *dev);
> extern int pm_clk_resume(struct device *dev);
> #else
> @@ -74,6 +76,9 @@ static inline void pm_clk_remove(struct device *dev, const char *con_id)
> }
> #define pm_clk_suspend NULL
> #define pm_clk_resume NULL
> +static inline void pm_clk_remove_clk(struct device *dev, struct clk *clk)
> +{
> +}
> #endif
>
> #ifdef CONFIG_HAVE_CLK
> @@ -86,4 +91,15 @@ static inline void pm_clk_add_notifier(struct bus_type *bus,
> }
> #endif
>
> +#if defined(CONFIG_PM_CLK) && defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
> +extern int of_pm_clk_add_clks(struct device *dev,
> + bool (*of_pm_clk_filter)(struct of_phandle_args *args));
> +#else
> +static inline int of_pm_clk_add_clks(struct device *dev,
> + bool (*of_pm_clk_filter)(struct of_phandle_args *args))
> +{
> + return -EINVAL;
> +}
> +#endif
> +
> #endif
> --
> 2.1.4
>
> --
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