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authorJon Hunter <jonathanh@nvidia.com>2016-03-15 11:33:40 +0000
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2016-03-17 02:32:04 +0100
commit02113ba93ea414b7113d64e42b87dc0720e3e578 (patch)
treed4a1c34d81214dbd79695c80b90a621d0d2f364f /drivers/base/power/clock_ops.c
parentb562e44f507e863c6792946e4e1b1449fbbac85d (diff)
downloadlinux-02113ba93ea414b7113d64e42b87dc0720e3e578.tar.bz2
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 <jonathanh@nvidia.com> Acked-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base/power/clock_ops.c')
-rw-r--r--drivers/base/power/clock_ops.c89
1 files changed, 89 insertions, 0 deletions
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.
@@ -198,6 +254,39 @@ 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.
*