irqchip/gic-pm: Update driver to use clk_bulk APIs

gic-pm driver is using pm-clk framework to manage clock resources, where
clocks remain always ON. This happens on Tegra devices which use BPMP
co-processor to manage the clocks. Calls to BPMP are always blocking and
hence it is necessary to enable/disable clocks during prepare/unprepare
phase respectively. When pm-clk is used, prepare count of clock is not
balanced until pm_clk_remove() happens. Clock is prepared in the driver
probe() and thus prepare count of clock remains non-zero, which in turn
keeps clock ON always.

Please note that above mentioned behavior is specific to Tegra devices
using BPMP for clock management and this should not be seen on other
devices. Though this patch uses clk_bulk APIs to address the mentioned
behavior, this works fine for all devices.

To simplify gic_get_clocks() API is removed and instead probe can do
necessary setup.
Suggested-by: Mohan Kumar D <mkumard@nvidia.com>
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-gic-pm.c

@@ -19,7 +19,6 @@
 #include <linux/of_irq.h>
 #include <linux/irqchip/arm-gic.h>
 #include <linux/platform_device.h>
-#include <linux/pm_clock.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
@@ -28,17 +27,27 @@ struct gic_clk_data {
 	const char *const *clocks;
 };
 
+struct gic_chip_pm {
+	struct gic_chip_data *chip_data;
+	const struct gic_clk_data *clk_data;
+	struct clk_bulk_data *clks;
+};
+
 static int gic_runtime_resume(struct device *dev)
 {
-	struct gic_chip_data *gic = dev_get_drvdata(dev);
+	struct gic_chip_pm *chip_pm = dev_get_drvdata(dev);
+	struct gic_chip_data *gic = chip_pm->chip_data;
+	const struct gic_clk_data *data = chip_pm->clk_data;
 	int ret;
 
-	ret = pm_clk_resume(dev);
-	if (ret)
+	ret = clk_bulk_prepare_enable(data->num_clocks, chip_pm->clks);
+	if (ret) {
+		dev_err(dev, "clk_enable failed: %d\n", ret);
 		return ret;
+	}
 
 	/*
-	 * On the very first resume, the pointer to the driver data
+	 * On the very first resume, the pointer to chip_pm->chip_data
 	 * will be NULL and this is intentional, because we do not
 	 * want to restore the GIC on the very first resume. So if
 	 * the pointer is not valid just return.
@@ -54,35 +63,14 @@ static int gic_runtime_resume(struct device *dev)
 
 static int gic_runtime_suspend(struct device *dev)
 {
-	struct gic_chip_data *gic = dev_get_drvdata(dev);
+	struct gic_chip_pm *chip_pm = dev_get_drvdata(dev);
+	struct gic_chip_data *gic = chip_pm->chip_data;
+	const struct gic_clk_data *data = chip_pm->clk_data;
 
 	gic_dist_save(gic);
 	gic_cpu_save(gic);
 
-	return pm_clk_suspend(dev);
-}
-
-static int gic_get_clocks(struct device *dev, const struct gic_clk_data *data)
-{
-	unsigned int i;
-	int ret;
-
-	if (!dev || !data)
-		return -EINVAL;
-
-	ret = pm_clk_create(dev);
-	if (ret)
-		return ret;
-
-	for (i = 0; i < data->num_clocks; i++) {
-		ret = of_pm_clk_add_clk(dev, data->clocks[i]);
-		if (ret) {
-			dev_err(dev, "failed to add clock %s\n",
-				data->clocks[i]);
-			pm_clk_destroy(dev);
-			return ret;
-		}
-	}
+	clk_bulk_disable_unprepare(data->num_clocks, chip_pm->clks);
 
 	return 0;
 }
@@ -91,8 +79,8 @@ static int gic_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	const struct gic_clk_data *data;
-	struct gic_chip_data *gic;
-	int ret, irq;
+	struct gic_chip_pm *chip_pm;
+	int ret, irq, i;
 
 	data = of_device_get_match_data(&pdev->dev);
 	if (!data) {
@@ -100,28 +88,41 @@ static int gic_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	chip_pm = devm_kzalloc(dev, sizeof(*chip_pm), GFP_KERNEL);
+	if (!chip_pm)
+		return -ENOMEM;
+
 	irq = irq_of_parse_and_map(dev->of_node, 0);
 	if (!irq) {
 		dev_err(dev, "no parent interrupt found!\n");
 		return -EINVAL;
 	}
 
-	ret = gic_get_clocks(dev, data);
+	chip_pm->clks = devm_kcalloc(dev, data->num_clocks,
+				     sizeof(*chip_pm->clks), GFP_KERNEL);
+	if (!chip_pm->clks)
+		return -ENOMEM;
+
+	for (i = 0; i < data->num_clocks; i++)
+		chip_pm->clks[i].id = data->clocks[i];
+
+	ret = devm_clk_bulk_get(dev, data->num_clocks, chip_pm->clks);
 	if (ret)
 		goto irq_dispose;
 
+	chip_pm->clk_data = data;
+	dev_set_drvdata(dev, chip_pm);
+
 	pm_runtime_enable(dev);
 
 	ret = pm_runtime_get_sync(dev);
 	if (ret < 0)
 		goto rpm_disable;
 
-	ret = gic_of_init_child(dev, &gic, irq);
+	ret = gic_of_init_child(dev, &chip_pm->chip_data, irq);
 	if (ret)
 		goto rpm_put;
 
-	platform_set_drvdata(pdev, gic);
-
 	pm_runtime_put(dev);
 
 	dev_info(dev, "GIC IRQ controller registered\n");
@@ -132,7 +133,6 @@ static int gic_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(dev);
 rpm_disable:
 	pm_runtime_disable(dev);
-	pm_clk_destroy(dev);
 irq_dispose:
 	irq_dispose_mapping(irq);