From 02113ba93ea414b7113d64e42b87dc0720e3e578 Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Tue, 15 Mar 2016 11:33:40 +0000 Subject: [PATCH] PM / clk: Add support for obtaining clocks from device-tree 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 it is not necessary to make the compilation of this new function dependent upon CONFIG_OF because there are stubs functions for the device-tree APIs used. 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 Acked-by: Geert Uytterhoeven Signed-off-by: Rafael J. Wysocki --- drivers/base/power/clock_ops.c | 89 ++++++++++++++++++++++++++++++++++ include/linux/pm_clock.h | 9 ++++ 2 files changed, 98 insertions(+) diff --git a/drivers/base/power/clock_ops.c b/drivers/base/power/clock_ops.c index 272a52ebafc0..0e64a1b5e62a 100644 --- a/drivers/base/power/clock_ops.c +++ b/drivers/base/power/clock_ops.c @@ -137,6 +137,62 @@ int pm_clk_add_clk(struct device *dev, struct clk *clk) return __pm_clk_add(dev, NULL, 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. + * + * 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. + * On success, returns the number of clocks added. Returns a negative + * error code if there are no clocks in the device node for the device + * or if adding a clock fails. + */ +int of_pm_clk_add_clks(struct device *dev) +{ + struct clk **clks; + unsigned int i, count; + 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++) { + clks[i] = of_clk_get(dev->of_node, i); + if (IS_ERR(clks[i])) { + ret = PTR_ERR(clks[i]); + goto error; + } + + ret = pm_clk_add_clk(dev, clks[i]); + if (ret) { + clk_put(clks[i]); + goto error; + } + } + + kfree(clks); + + return i; + +error: + while (i--) + pm_clk_remove_clk(dev, clks[i]); + + kfree(clks); + + return ret; +} + /** * __pm_clk_remove - Destroy PM clock entry. * @ce: PM clock entry to destroy. @@ -197,6 +253,39 @@ void pm_clk_remove(struct device *dev, const char *con_id) __pm_clk_remove(ce); } +/** + * 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..308d6044f153 100644 --- a/include/linux/pm_clock.h +++ b/include/linux/pm_clock.h @@ -42,7 +42,9 @@ extern int pm_clk_create(struct device *dev); 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 int of_pm_clk_add_clks(struct device *dev); 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 @@ -69,11 +71,18 @@ static inline int pm_clk_add_clk(struct device *dev, struct clk *clk) { return -EINVAL; } +static inline int of_pm_clk_add_clks(struct device *dev) +{ + return -EINVAL; +} 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 -- 2.34.1