[PATCH v2 3/7] clocksource: sh_tmu: Add OF support

[Bastian Hecht <hechtb@gmail.com>]

We add the capabilty to probe SH CMT timer devices using Device Tree
setup.

Signed-off-by: Bastian Hecht <hechtb+renesas@gmail.com>
---
v2: new. Done analogously to the cmt driver

 drivers/clocksource/sh_tmu.c |   94 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 83 insertions(+), 11 deletions(-)

diff --git a/drivers/clocksource/sh_tmu.c b/drivers/clocksource/sh_tmu.c
index b4502edc..7d5c999 100644
--- a/drivers/clocksource/sh_tmu.c
+++ b/drivers/clocksource/sh_tmu.c
@@ -34,10 +34,13 @@
 #include <linux/module.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
+#include <linux/of.h>
 
 struct sh_tmu_priv {
 	void __iomem *mapbase;
 	struct clk *clk;
+	long channel_offset;
+	int timer_bit;
 	struct irqaction irqaction;
 	struct platform_device *pdev;
 	unsigned long rate;
@@ -57,12 +60,11 @@ static DEFINE_RAW_SPINLOCK(sh_tmu_lock);
 
 static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
 {
-	struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 	void __iomem *base = p->mapbase;
 	unsigned long offs;
 
 	if (reg_nr = TSTR)
-		return ioread8(base - cfg->channel_offset);
+		return ioread8(base - p->channel_offset);
 
 	offs = reg_nr << 2;
 
@@ -75,12 +77,11 @@ static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
 static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
 				unsigned long value)
 {
-	struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 	void __iomem *base = p->mapbase;
 	unsigned long offs;
 
 	if (reg_nr = TSTR) {
-		iowrite8(value, base - cfg->channel_offset);
+		iowrite8(value, base - p->channel_offset);
 		return;
 	}
 
@@ -94,7 +95,6 @@ static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
 
 static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
 {
-	struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 	unsigned long flags, value;
 
 	/* start stop register shared by multiple timer channels */
@@ -102,9 +102,9 @@ static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
 	value = sh_tmu_read(p, TSTR);
 
 	if (start)
-		value |= 1 << cfg->timer_bit;
+		value |= 1 << p->timer_bit;
 	else
-		value &= ~(1 << cfg->timer_bit);
+		value &= ~(1 << p->timer_bit);
 
 	sh_tmu_write(p, TSTR, value);
 	raw_spin_unlock_irqrestore(&sh_tmu_lock, flags);
@@ -421,9 +421,75 @@ static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
 	return 0;
 }
 
-static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
+static const struct of_device_id of_sh_tmu_match[] = {
+	{ .compatible = "renesas,tmu-timer" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_sh_tmu_match);
+
+#define TMU_OFFSET_MULTIPLIER	0xc
+#define TMU_MAX_CHANNELS	3
+
+static struct sh_timer_config *sh_tmu_parse_dt(struct device *dev)
+{
+	struct sh_timer_config *cfg;
+	struct device_node *np = dev->of_node;
+	u32 channel_id, rating;
+
+	if (!IS_ENABLED(CONFIG_OF) || !np)
+		return NULL;
+
+	cfg = devm_kzalloc(dev, sizeof(struct sh_timer_config), GFP_KERNEL);
+	if (!cfg) {
+		dev_err(dev, "failed to allocate DT config data\n");
+		return NULL;
+	}
+
+	if (of_property_read_u32(np, "renesas,channel-id", &channel_id)) {
+		dev_err(dev, "channel id missing\n");
+		return NULL;
+	}
+	if (channel_id >= TMU_MAX_CHANNELS) {
+		dev_err(dev, "invalid channel id\n");
+		return NULL;
+	}
+
+	cfg->channel_offset = channel_id * TMU_OFFSET_MULTIPLIER + 4;
+	cfg->timer_bit = channel_id;
+
+	/*
+	 * We convert the {source,event}-quality DT properties to linux specific
+	 * clock{source,event}_ratings.
+	 */
+	if (!of_property_read_u32(np, "renesas,source-quality", &rating)) {
+		if (rating > 10) {
+			dev_err(dev, "invalid source-quality\n");
+			return NULL;
+		}
+		if (rating)
+			cfg->clocksource_rating = rating * 50 - 1;
+	}
+
+	if (!of_property_read_u32(np, "renesas,event-quality", &rating)) {
+		if (rating > 10) {
+			dev_err(dev, "invalid event-quality\n");
+			return NULL;
+		}
+		if (rating)
+			cfg->clockevent_rating = rating * 50 - 1;
+	}
+
+	if (!cfg->clocksource_rating && !cfg->clockevent_rating) {
+		dev_err(dev, "source- and event-quality 0, timer is unused\n");
+		return NULL;
+	}
+
+	return cfg;
+}
+
+static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev,
+						struct sh_timer_config *cfg)
 {
-	struct sh_timer_config *cfg = pdev->dev.platform_data;
 	struct resource *res;
 	int irq, ret;
 	ret = -ENXIO;
@@ -487,7 +553,7 @@ static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
 static int sh_tmu_probe(struct platform_device *pdev)
 {
 	struct sh_tmu_priv *p = platform_get_drvdata(pdev);
-	struct sh_timer_config *cfg = pdev->dev.platform_data;
+	struct sh_timer_config *cfg;
 	int ret;
 
 	if (!is_early_platform_device(pdev)) {
@@ -495,6 +561,11 @@ static int sh_tmu_probe(struct platform_device *pdev)
 		pm_runtime_enable(&pdev->dev);
 	}
 
+	if (pdev->dev.of_node)
+		cfg = sh_tmu_parse_dt(&pdev->dev);
+	else
+		cfg = pdev->dev.platform_data;
+
 	if (p) {
 		dev_info(&pdev->dev, "kept as earlytimer\n");
 		goto out;
@@ -506,7 +577,7 @@ static int sh_tmu_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	ret = sh_tmu_setup(p, pdev);
+	ret = sh_tmu_setup(p, pdev, cfg);
 	if (ret) {
 		kfree(p);
 		platform_set_drvdata(pdev, NULL);
@@ -535,6 +606,7 @@ static struct platform_driver sh_tmu_device_driver = {
 	.remove		= sh_tmu_remove,
 	.driver		= {
 		.name	= "sh_tmu",
+		.of_match_table = of_sh_tmu_match,
 	}
 };
 
-- 
1.7.9.5