[PATCH v4 4/7] drm/panfrost: Add support for multiple regulators

[Nicolas Boichat <drinkcat@chromium.org>]

Some GPUs, namely, the bifrost/g72 part on MT8183, have a second
regulator for their SRAM, let's add support for that.

We extend the framework in a generic manner so that we could
support more than 2 regulators, if required.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>

---

v4:
 - nits: Run through latest version of checkpatch:
   - Use WARN instead of BUG_ON.
   - Drop braces in single expression for loop.
   - *comp not * comp
v3:
 - Make this more generic, by allowing any number of regulators
   (in practice we fix the maximum number of regulators to 2, but
   this could be increased easily).
 - We only probe the second regulator if the device tree matching
   data asks for it.
 - I couldn't find a way to detect the number of regulators in the
   device tree, if we wanted to refuse to probe the device if there
   are too many regulators, which might be required for safety, see
   the thread on v2 [1].
 - The discussion also included the idea of a separate device tree
   entry for a "soft PDC", or at least a separate driver. I'm not
   sure to understand the full picture, and how different vendors
   implement this, so I'm still integrating everything in the main
   driver. I'd be happy to try to make mt8183 fit into such a
   framework after it's created, but I don't think I'm best placed
   to implement (and again, the main purpose of this was to test
   if the binding is correct).

[1] https://patchwork.kernel.org/patch/11322839/

 drivers/gpu/drm/panfrost/panfrost_device.c | 26 +++++++++++++-------
 drivers/gpu/drm/panfrost/panfrost_device.h | 15 +++++++++++-
 drivers/gpu/drm/panfrost/panfrost_drv.c    | 28 +++++++++++++++-------
 3 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
index 238fb6d54df4732..3720d50f6d9f965 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.c
+++ b/drivers/gpu/drm/panfrost/panfrost_device.c
@@ -87,18 +87,27 @@ static void panfrost_clk_fini(struct panfrost_device *pfdev)
 
 static int panfrost_regulator_init(struct panfrost_device *pfdev)
 {
-	int ret;
+	int ret, i;
 
-	pfdev->regulator = devm_regulator_get(pfdev->dev, "mali");
-	if (IS_ERR(pfdev->regulator)) {
-		ret = PTR_ERR(pfdev->regulator);
-		dev_err(pfdev->dev, "failed to get regulator: %d\n", ret);
+	if (WARN(pfdev->comp->num_supplies > ARRAY_SIZE(pfdev->regulators),
+			"Too many supplies in compatible structure.\n"))
+		return -EINVAL;
+
+	for (i = 0; i < pfdev->comp->num_supplies; i++)
+		pfdev->regulators[i].supply = pfdev->comp->supply_names[i];
+
+	ret = devm_regulator_bulk_get(pfdev->dev,
+				      pfdev->comp->num_supplies,
+				      pfdev->regulators);
+	if (ret < 0) {
+		dev_err(pfdev->dev, "failed to get regulators: %d\n", ret);
 		return ret;
 	}
 
-	ret = regulator_enable(pfdev->regulator);
+	ret = regulator_bulk_enable(pfdev->comp->num_supplies,
+				    pfdev->regulators);
 	if (ret < 0) {
-		dev_err(pfdev->dev, "failed to enable regulator: %d\n", ret);
+		dev_err(pfdev->dev, "failed to enable regulators: %d\n", ret);
 		return ret;
 	}
 
@@ -107,7 +116,8 @@ static int panfrost_regulator_init(struct panfrost_device *pfdev)
 
 static void panfrost_regulator_fini(struct panfrost_device *pfdev)
 {
-	regulator_disable(pfdev->regulator);
+	regulator_bulk_disable(pfdev->comp->num_supplies,
+			pfdev->regulators);
 }
 
 int panfrost_device_init(struct panfrost_device *pfdev)
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 06713811b92cdf7..c9468bc5573ac9d 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -7,6 +7,7 @@
 
 #include <linux/atomic.h>
 #include <linux/io-pgtable.h>
+#include <linux/regulator/consumer.h>
 #include <linux/spinlock.h>
 #include <drm/drm_device.h>
 #include <drm/drm_mm.h>
@@ -19,6 +20,7 @@ struct panfrost_job;
 struct panfrost_perfcnt;
 
 #define NUM_JOB_SLOTS 3
+#define MAX_REGULATORS 2
 
 struct panfrost_features {
 	u16 id;
@@ -51,6 +53,16 @@ struct panfrost_features {
 	unsigned long hw_issues[64 / BITS_PER_LONG];
 };
 
+/*
+ * Features that cannot be automatically detected and need matching using the
+ * compatible string, typically SoC-specific.
+ */
+struct panfrost_compatible {
+	/* Supplies count and names. */
+	int num_supplies;
+	const char * const *supply_names;
+};
+
 struct panfrost_device {
 	struct device *dev;
 	struct drm_device *ddev;
@@ -59,10 +71,11 @@ struct panfrost_device {
 	void __iomem *iomem;
 	struct clk *clock;
 	struct clk *bus_clock;
-	struct regulator *regulator;
+	struct regulator_bulk_data regulators[MAX_REGULATORS];
 	struct reset_control *rstc;
 
 	struct panfrost_features features;
+	const struct panfrost_compatible *comp;
 
 	spinlock_t as_lock;
 	unsigned long as_in_use_mask;
diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c b/drivers/gpu/drm/panfrost/panfrost_drv.c
index b7a618db3ee223e..4d08507526239f2 100644
--- a/drivers/gpu/drm/panfrost/panfrost_drv.c
+++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
@@ -584,6 +584,10 @@ static int panfrost_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pfdev);
 
+	pfdev->comp = of_device_get_match_data(&pdev->dev);
+	if (!pfdev->comp)
+		return -ENODEV;
+
 	/* Allocate and initialze the DRM device. */
 	ddev = drm_dev_alloc(&panfrost_drm_driver, &pdev->dev);
 	if (IS_ERR(ddev))
@@ -655,16 +659,22 @@ static int panfrost_remove(struct platform_device *pdev)
 	return 0;
 }
 
+const char * const default_supplies[] = { "mali" };
+static const struct panfrost_compatible default_data = {
+	.num_supplies = ARRAY_SIZE(default_supplies),
+	.supply_names = default_supplies,
+};
+
 static const struct of_device_id dt_match[] = {
-	{ .compatible = "arm,mali-t604" },
-	{ .compatible = "arm,mali-t624" },
-	{ .compatible = "arm,mali-t628" },
-	{ .compatible = "arm,mali-t720" },
-	{ .compatible = "arm,mali-t760" },
-	{ .compatible = "arm,mali-t820" },
-	{ .compatible = "arm,mali-t830" },
-	{ .compatible = "arm,mali-t860" },
-	{ .compatible = "arm,mali-t880" },
+	{ .compatible = "arm,mali-t604", .data = &default_data, },
+	{ .compatible = "arm,mali-t624", .data = &default_data, },
+	{ .compatible = "arm,mali-t628", .data = &default_data, },
+	{ .compatible = "arm,mali-t720", .data = &default_data, },
+	{ .compatible = "arm,mali-t760", .data = &default_data, },
+	{ .compatible = "arm,mali-t820", .data = &default_data, },
+	{ .compatible = "arm,mali-t830", .data = &default_data, },
+	{ .compatible = "arm,mali-t860", .data = &default_data, },
+	{ .compatible = "arm,mali-t880", .data = &default_data, },
 	{}
 };
 MODULE_DEVICE_TABLE(of, dt_match);
-- 
2.25.0.341.g760bfbb309-goog