From 332b2ceea539c6dc84d7478aa89f96317060e7f9 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Thu, 14 Apr 2016 15:13:53 -0700
Subject: [PATCH] clk: bcm2835: Do appropriate name lookups for DSI1's parents
 as well.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 .../bindings/clock/brcm,bcm2835-cprman.txt         | 12 ++++-
 drivers/clk/bcm/clk-bcm2835.c                      | 54 +++++++++++++++++-----
 2 files changed, 54 insertions(+), 12 deletions(-)

--- a/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt
+++ b/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt
@@ -16,7 +16,17 @@ Required properties:
 - #clock-cells:	Should be <1>. The permitted clock-specifier values can be
 		  found in include/dt-bindings/clock/bcm2835.h
 - reg:		Specifies base physical address and size of the registers
-- clocks:	The external oscillator clock phandle
+- clocks:	phandles to the parent clocks used as input to the module, in
+		  the following order:
+
+		  - External oscillator
+		  - DSI1 byte clock
+		  - DSI1 DDR2 clock
+		  - DSI1 DDR clock
+
+		  Only external oscillator is required.  The DSI clocks may
+		  not be present, in which case their children will be
+		  unusable.
 
 Example:
 
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -297,11 +297,29 @@
 #define LOCK_TIMEOUT_NS		100000000
 #define BCM2835_MAX_FB_RATE	1750000000u
 
+/*
+ * Names of clocks used within the driver that need to be replaced
+ * with an external parent's name.  This array is in the order that
+ * the clocks node in the DT references external clocks.
+ */
+static const char *cprman_parent_names[] = {
+	"xosc",
+	"dsi1_byte",
+	"dsi1_ddr2",
+	"dsi1_ddr",
+};
+
 struct bcm2835_cprman {
 	struct device *dev;
 	void __iomem *regs;
 	spinlock_t regs_lock; /* spinlock for all clocks */
-	const char *osc_name;
+
+	/*
+	 * Real names of cprman clock parents looked up through
+	 * of_clk_get_parent_name(), which will be used in the
+	 * parent_names[] arrays for clock registration.
+	 */
+	const char *real_parent_names[ARRAY_SIZE(cprman_parent_names)];
 
 	struct clk_onecell_data onecell;
 	struct clk *clks[];
@@ -1176,7 +1194,7 @@ static struct clk *bcm2835_register_pll(
 	memset(&init, 0, sizeof(init));
 
 	/* All of the PLLs derive from the external oscillator. */
-	init.parent_names = &cprman->osc_name;
+	init.parent_names = &cprman->real_parent_names[0];
 	init.num_parents = 1;
 	init.name = data->name;
 	init.ops = &bcm2835_pll_clk_ops;
@@ -1259,17 +1277,21 @@ static struct clk *bcm2835_register_cloc
 	struct bcm2835_clock *clock;
 	struct clk_init_data init;
 	const char *parents[1 << CM_SRC_BITS];
-	size_t i;
+	size_t i, j;
 
 	/*
-	 * Replace our "xosc" references with the oscillator's
-	 * actual name.
+	 * Replace our strings referencing parent clocks with the
+	 * actual clock-output-name of the parent.
 	 */
 	for (i = 0; i < data->num_mux_parents; i++) {
-		if (strcmp(data->parents[i], "xosc") == 0)
-			parents[i] = cprman->osc_name;
-		else
-			parents[i] = data->parents[i];
+		parents[i] = data->parents[i];
+
+		for (j = 0; j < ARRAY_SIZE(cprman_parent_names); j++) {
+			if (strcmp(parents[i], cprman_parent_names[j]) == 0) {
+				parents[i] = cprman->real_parent_names[j];
+				break;
+			}
+		}
 	}
 
 	memset(&init, 0, sizeof(init));
@@ -1891,8 +1913,18 @@ static int bcm2835_clk_probe(struct plat
 	if (IS_ERR(cprman->regs))
 		return PTR_ERR(cprman->regs);
 
-	cprman->osc_name = of_clk_get_parent_name(dev->of_node, 0);
-	if (!cprman->osc_name)
+	for (i = 0; i < ARRAY_SIZE(cprman_parent_names); i++) {
+		cprman->real_parent_names[i] =
+			of_clk_get_parent_name(dev->of_node, i);
+	}
+	/*
+	 * Make sure the external oscillator has been registered.
+	 *
+	 * The other (DSI) clocks are not present on older device
+	 * trees, which we still need to support for backwards
+	 * compatibility.
+	 */
+	if (!cprman->real_parent_names[0])
 		return -ENODEV;
 
 	platform_set_drvdata(pdev, cprman);
