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Message-ID: <1457529213-2581-1-git-send-email-jonathanh@nvidia.com>
Date: Wed, 9 Mar 2016 13:13:33 +0000
From: Jon Hunter <jonathanh@...dia.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
CC: Geert Uytterhoeven <geert@...ux-m68k.org>,
linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-tegra@...r.kernel.org, Jon Hunter <jonathanh@...dia.com>
Subject: [PATCH V2] 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
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.
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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