[PATCH 6/6] msm/drm: gpu: Dynamically locate the clocks from the device tree

[Jordan Crouse]

Instead of using a fixed list of clock names use the clock-names
list in the device tree to discover and get the list of clocks
that we need.

Signed-off-by: Jordan Crouse <jcrouse at codeaurora.org>
---
 drivers/gpu/drm/msm/msm_gpu.c | 76 ++++++++++++++++++++++++++++++-------------
 drivers/gpu/drm/msm/msm_gpu.h |  4 ++-
 2 files changed, 57 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 2b731e7..25de46f 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -93,18 +93,18 @@ static int enable_clk(struct msm_gpu *gpu)
 {
 	int i;
 
-	if (gpu->grp_clks[0] && gpu->fast_rate)
-		clk_set_rate(gpu->grp_clks[0], gpu->fast_rate);
+	if (gpu->core_clk && gpu->fast_rate)
+		clk_set_rate(gpu->core_clk, gpu->fast_rate);
 
 	/* Set the RBBM timer rate to 19.2Mhz */
-	if (gpu->grp_clks[2])
-		clk_set_rate(gpu->grp_clks[2], 19200000);
+	if (gpu->rbbmtimer_clk)
+		clk_set_rate(gpu->rbbmtimer_clk, 19200000);
 
-	for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i >= 0; i--)
+	for (i = gpu->nr_clocks - 1; i >= 0; i--)
 		if (gpu->grp_clks[i])
 			clk_prepare(gpu->grp_clks[i]);
 
-	for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i >= 0; i--)
+	for (i = gpu->nr_clocks - 1; i >= 0; i--)
 		if (gpu->grp_clks[i])
 			clk_enable(gpu->grp_clks[i]);
 
@@ -115,11 +115,11 @@ static int disable_clk(struct msm_gpu *gpu)
 {
 	int i;
 
-	for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i >= 0; i--)
+	for (i = gpu->nr_clocks - 1; i >= 0; i--)
 		if (gpu->grp_clks[i])
 			clk_disable(gpu->grp_clks[i]);
 
-	for (i = ARRAY_SIZE(gpu->grp_clks) - 1; i >= 0; i--)
+	for (i = gpu->nr_clocks - 1; i >= 0; i--)
 		if (gpu->grp_clks[i])
 			clk_unprepare(gpu->grp_clks[i]);
 
@@ -128,10 +128,11 @@ static int disable_clk(struct msm_gpu *gpu)
 	 * speed had to be non zero to avoid problems. On newer targets this
 	 * will be rounded down to zero anyway so it all works out.
 	 */
-	clk_set_rate(gpu->grp_clks[0], 27000000);
+	if (gpu->core_clk)
+		clk_set_rate(gpu->core_clk, 27000000);
 
-	if (gpu->grp_clks[2])
-		clk_set_rate(gpu->grp_clks[2], 0);
+	if (gpu->rbbmtimer_clk)
+		clk_set_rate(gpu->rbbmtimer_clk, 0);
 
 	return 0;
 }
@@ -586,9 +587,45 @@ static irqreturn_t irq_handler(int irq, void *data)
 	return gpu->funcs->irq(gpu);
 }
 
-static const char *clk_names[] = {
-	"core", "iface", "rbbmtimer", "mem", "mem_iface", "alt_mem_iface",
-};
+static struct clk *get_clock(struct device *dev, const char *name)
+{
+	struct clk *clk = devm_clk_get(dev, name);
+
+	return IS_ERR(clk) ? NULL : clk;
+}
+
+static int get_clocks(struct platform_device *pdev, struct msm_gpu *gpu)
+{
+	struct device *dev = &pdev->dev;
+	struct property *prop;
+	const char *name;
+	int i = 0;
+
+	gpu->nr_clocks = of_property_count_strings(dev->of_node, "clock-names");
+	if (gpu->nr_clocks < 1) {
+		gpu->nr_clocks = 0;
+		return 0;
+	}
+
+	gpu->grp_clks = devm_kcalloc(dev, sizeof(struct clk *), gpu->nr_clocks,
+		GFP_KERNEL);
+	if (!gpu->grp_clks)
+		return -ENOMEM;
+
+	of_property_for_each_string(dev->of_node, "clock-names", prop, name) {
+		gpu->grp_clks[i] = get_clock(dev, name);
+
+		/* Remember the key clocks that we need to control later */
+		if (!strcmp(name, "core"))
+			gpu->core_clk = gpu->grp_clks[i];
+		else if (!strcmp(name, "rbbmtimer"))
+			gpu->rbbmtimer_clk = gpu->grp_clks[i];
+
+		++i;
+	}
+
+	return 0;
+}
 
 int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		struct msm_gpu *gpu, const struct msm_gpu_funcs *funcs,
@@ -625,7 +662,6 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 
 	spin_lock_init(&gpu->perf_lock);
 
-	BUG_ON(ARRAY_SIZE(clk_names) != ARRAY_SIZE(gpu->grp_clks));
 
 	/* Map registers: */
 	gpu->mmio = msm_ioremap(pdev, config->ioname, name);
@@ -649,13 +685,9 @@ int msm_gpu_init(struct drm_device *drm, struct platform_device *pdev,
 		goto fail;
 	}
 
-	/* Acquire clocks: */
-	for (i = 0; i < ARRAY_SIZE(clk_names); i++) {
-		gpu->grp_clks[i] = msm_clk_get(pdev, clk_names[i]);
-		DBG("grp_clks[%s]: %p", clk_names[i], gpu->grp_clks[i]);
-		if (IS_ERR(gpu->grp_clks[i]))
-			gpu->grp_clks[i] = NULL;
-	}
+	ret = get_clocks(pdev, gpu);
+	if (ret)
+		goto fail;
 
 	gpu->ebi1_clk = msm_clk_get(pdev, "bus");
 	DBG("ebi1_clk: %p", gpu->ebi1_clk);
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index bc6f163..4162028 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -110,7 +110,9 @@ struct msm_gpu {
 
 	/* Power Control: */
 	struct regulator *gpu_reg, *gpu_cx;
-	struct clk *ebi1_clk, *grp_clks[6];
+	struct clk **grp_clks;
+	int nr_clocks;
+	struct clk *ebi1_clk, *core_clk, *rbbmtimer_clk;
 	uint32_t fast_rate, bus_freq;
 
 #ifdef DOWNSTREAM_CONFIG_MSM_BUS_SCALING
-- 
1.9.1