[PATCH v3 4/6] exynos4-is: Add clock provider for the external clocks

[Sylwester Nawrocki <s.nawrocki@samsung.com>]

This patch adds clock provider to expose the sclk_cam0/1 clocks
for external image sensor devices.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
Changes since v2:
 - use 'camera' DT node drirectly as clock provider node, rather than
  creating additional clock-controller child node.
---
 .../devicetree/bindings/media/samsung-fimc.txt     |   15 ++-
 drivers/media/platform/exynos4-is/media-dev.c      |  108 ++++++++++++++++++++
 drivers/media/platform/exynos4-is/media-dev.h      |   18 +++-
 3 files changed, 137 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/media/samsung-fimc.txt b/Documentation/devicetree/bindings/media/samsung-fimc.txt
index 96312f6..968e065 100644
--- a/Documentation/devicetree/bindings/media/samsung-fimc.txt
+++ b/Documentation/devicetree/bindings/media/samsung-fimc.txt
@@ -32,6 +32,15 @@ way around.
 
 The 'camera' node must include at least one 'fimc' child node.
 
+Optional properties:
+
+- #clock-cells: from the common clock bindings (../clock/clock-bindings.txt),
+  must be 1. A clock provider is associated with the camera node and it should
+  be referenced by external sensors that use clocks provided by the SoC on
+  CAM_*_CLKOUT pins. The second cell of the clock specifier is a clock's index.
+  The indexes are 0, 1 for CAM_A_CLKOUT, CAM_B_CLKOUT clocks respectively.
+
+
 'fimc' device nodes
 -------------------
 
@@ -114,7 +123,7 @@ Example:
 			vddio-supply = <...>;
 
 			clock-frequency = <24000000>;
-			clocks = <...>;
+			clocks = <&camera 1>;
 			clock-names = "mclk";
 
 			port {
@@ -135,7 +144,7 @@ Example:
 			vddio-supply = <...>;
 
 			clock-frequency = <24000000>;
-			clocks = <...>;
+			clocks = <&camera 0>;
 			clock-names = "mclk";
 
 			port {
@@ -151,8 +160,8 @@ Example:
 		compatible = "samsung,fimc", "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;
+		#clock-cells = <1>;
 		status = "okay";
-
 		pinctrl-names = "default";
 		pinctrl-0 = <&cam_port_a_clk_active>;
 
diff --git a/drivers/media/platform/exynos4-is/media-dev.c b/drivers/media/platform/exynos4-is/media-dev.c
index a835112..d78e3da 100644
--- a/drivers/media/platform/exynos4-is/media-dev.c
+++ b/drivers/media/platform/exynos4-is/media-dev.c
@@ -11,6 +11,8 @@
  */
 
 #include <linux/bug.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
@@ -1437,6 +1439,101 @@ static int fimc_md_get_pinctrl(struct fimc_md *fmd)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static int cam_clk_prepare(struct clk_hw *hw)
+{
+	struct cam_clk *camclk = to_cam_clk(hw);
+	int ret;
+
+	if (camclk->fmd->pmf == NULL)
+		return -ENODEV;
+
+	ret = pm_runtime_get_sync(camclk->fmd->pmf);
+	return ret < 0 ? ret : 0;
+}
+
+static void cam_clk_unprepare(struct clk_hw *hw)
+{
+	struct cam_clk *camclk = to_cam_clk(hw);
+
+	if (camclk->fmd->pmf == NULL)
+		return;
+
+	pm_runtime_put_sync(camclk->fmd->pmf);
+}
+
+static const struct clk_ops cam_clk_ops = {
+	.prepare = cam_clk_prepare,
+	.unprepare = cam_clk_unprepare,
+};
+
+static const char *cam_clk_p_names[] = { "sclk_cam0", "sclk_cam1" };
+
+static void fimc_md_unregister_clk_provider(struct fimc_md *fmd)
+{
+	struct cam_clk_provider *cp = &fmd->clk_provider;
+	unsigned int i;
+
+	if (cp->of_node)
+		of_clk_del_provider(cp->of_node);
+
+	for (i = 0; i < ARRAY_SIZE(cp->clks); i++)
+		if (!IS_ERR(cp->clks[i]))
+			clk_unregister(cp->clks[i]);
+}
+
+static int fimc_md_register_clk_provider(struct fimc_md *fmd)
+{
+	struct cam_clk_provider *cp = &fmd->clk_provider;
+	struct device *dev = &fmd->pdev->dev;
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(cp->clks); i++)
+		cp->clks[i] = ERR_PTR(-EINVAL);
+
+	for (i = 0; i < FIMC_MAX_CAMCLKS; i++) {
+		struct cam_clk *camclk = &cp->camclk[i];
+		struct clk_init_data init;
+		char clk_name[16];
+		struct clk *clk;
+
+		snprintf(clk_name, sizeof(clk_name), "cam_clkout%d", i);
+
+		init.name = clk_name;
+		init.ops = &cam_clk_ops;
+		init.flags = CLK_SET_RATE_PARENT;
+		init.parent_names = &cam_clk_p_names[i];
+		init.num_parents = 1;
+		camclk->hw.init = &init;
+		camclk->fmd = fmd;
+
+		clk = clk_register(dev, &camclk->hw);
+		if (IS_ERR(clk)) {
+			dev_err(dev, "failed to register clock: %s (%ld)\n",
+						clk_name, PTR_ERR(clk));
+			ret = PTR_ERR(clk);
+			goto err;
+		}
+		cp->clks[i] = clk;
+	}
+
+	cp->clk_data.clks = cp->clks;
+	cp->clk_data.clk_num = i;
+	cp->of_node = dev->of_node;
+
+	ret = of_clk_add_provider(dev->of_node, of_clk_src_onecell_get,
+				  &cp->clk_data);
+	if (!ret)
+		return 0;
+err:
+	fimc_md_unregister_clk_provider(fmd);
+	return ret;
+}
+#else
+#define fimc_md_register_clk_provider(fmd) (0)
+#define fimc_md_unregister_clk_provider(fmd) (0)
+#endif
+
 static int fimc_md_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1464,16 +1561,24 @@ static int fimc_md_probe(struct platform_device *pdev)
 
 	fmd->use_isp = fimc_md_is_isp_available(dev->of_node);
 
+	ret = fimc_md_register_clk_provider(fmd);
+	if (ret < 0) {
+		v4l2_err(v4l2_dev, "clock provider registration failed\n");
+		return ret;
+	}
+
 	ret = v4l2_device_register(dev, &fmd->v4l2_dev);
 	if (ret < 0) {
 		v4l2_err(v4l2_dev, "Failed to register v4l2_device: %d\n", ret);
 		return ret;
 	}
+
 	ret = media_device_register(&fmd->media_dev);
 	if (ret < 0) {
 		v4l2_err(v4l2_dev, "Failed to register media device: %d\n", ret);
 		goto err_md;
 	}
+
 	ret = fimc_md_get_clocks(fmd);
 	if (ret)
 		goto err_clk;
@@ -1507,6 +1612,7 @@ static int fimc_md_probe(struct platform_device *pdev)
 	ret = fimc_md_create_links(fmd);
 	if (ret)
 		goto err_unlock;
+
 	ret = v4l2_device_register_subdev_nodes(&fmd->v4l2_dev);
 	if (ret)
 		goto err_unlock;
@@ -1527,6 +1633,7 @@ err_clk:
 	media_device_unregister(&fmd->media_dev);
 err_md:
 	v4l2_device_unregister(&fmd->v4l2_dev);
+	fimc_md_unregister_clk_provider(fmd);
 	return ret;
 }
 
@@ -1537,6 +1644,7 @@ static int fimc_md_remove(struct platform_device *pdev)
 	if (!fmd)
 		return 0;
 
+	fimc_md_unregister_clk_provider(fmd);
 	v4l2_device_unregister(&fmd->v4l2_dev);
 	device_remove_file(&pdev->dev, &dev_attr_subdev_conf_mode);
 	fimc_md_unregister_entities(fmd);
diff --git a/drivers/media/platform/exynos4-is/media-dev.h b/drivers/media/platform/exynos4-is/media-dev.h
index 62599fd..240ca71 100644
--- a/drivers/media/platform/exynos4-is/media-dev.h
+++ b/drivers/media/platform/exynos4-is/media-dev.h
@@ -10,6 +10,7 @@
 #define FIMC_MDEVICE_H_
 
 #include <linux/clk.h>
+#include <linux/clk-provider.h>
 #include <linux/platform_device.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
@@ -89,6 +90,12 @@ struct fimc_sensor_info {
 	struct fimc_dev *host;
 };
 
+struct cam_clk {
+	struct clk_hw hw;
+	struct fimc_md *fmd;
+};
+#define to_cam_clk(_hw) container_of(_hw, struct cam_clk, hw)
+
 /**
  * struct fimc_md - fimc media device information
  * @csis: MIPI CSIS subdevs data
@@ -105,6 +112,7 @@ struct fimc_sensor_info {
  * @pinctrl: camera port pinctrl handle
  * @state_default: pinctrl default state handle
  * @state_idle: pinctrl idle state handle
+ * @cam_clk_provider: CAMCLK clock provider structure
  * @user_subdev_api: true if subdevs are not configured by the host driver
  * @slock: spinlock protecting @sensor array
  */
@@ -122,13 +130,21 @@ struct fimc_md {
 	struct media_device media_dev;
 	struct v4l2_device v4l2_dev;
 	struct platform_device *pdev;
+
 	struct fimc_pinctrl {
 		struct pinctrl *pinctrl;
 		struct pinctrl_state *state_default;
 		struct pinctrl_state *state_idle;
 	} pinctl;
-	bool user_subdev_api;
 
+	struct cam_clk_provider {
+		struct clk *clks[FIMC_MAX_CAMCLKS];
+		struct clk_onecell_data clk_data;
+		struct device_node *of_node;
+		struct cam_clk camclk[FIMC_MAX_CAMCLKS];
+	} clk_provider;
+
+	bool user_subdev_api;
 	spinlock_t slock;
 	struct list_head pipelines;
 };
-- 
1.7.9.5