[PATCH v4 2/7] clocksource: sh_cmt: Add OF support

[Bastian Hecht]

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

Signed-off-by: Bastian Hecht <hechtb+renesas at gmail.com>
---
v4:
Moved the assignments of p->channel_offset and p->timer_bit so that
they are ready as soon as setup_irq() is called

 drivers/clocksource/sh_cmt.c |  108 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 95 insertions(+), 13 deletions(-)

diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c
index 08d0c41..66a12e9 100644
--- a/drivers/clocksource/sh_cmt.c
+++ b/drivers/clocksource/sh_cmt.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_cmt_priv {
 	void __iomem *mapbase;
 	struct clk *clk;
+	long channel_offset;
+	int timer_bit;
 	unsigned long width; /* 16 or 32 bit version of hardware block */
 	unsigned long overflow_bit;
 	unsigned long clear_bits;
@@ -109,9 +112,7 @@ static void sh_cmt_write32(void __iomem *base, unsigned long offs,
 
 static inline unsigned long sh_cmt_read_cmstr(struct sh_cmt_priv *p)
 {
-	struct sh_timer_config *cfg = p->pdev->dev.platform_data;
-
-	return p->read_control(p->mapbase - cfg->channel_offset, 0);
+	return p->read_control(p->mapbase - p->channel_offset, 0);
 }
 
 static inline unsigned long sh_cmt_read_cmcsr(struct sh_cmt_priv *p)
@@ -127,9 +128,7 @@ static inline unsigned long sh_cmt_read_cmcnt(struct sh_cmt_priv *p)
 static inline void sh_cmt_write_cmstr(struct sh_cmt_priv *p,
 				      unsigned long value)
 {
-	struct sh_timer_config *cfg = p->pdev->dev.platform_data;
-
-	p->write_control(p->mapbase - cfg->channel_offset, 0, value);
+	p->write_control(p->mapbase - p->channel_offset, 0, value);
 }
 
 static inline void sh_cmt_write_cmcsr(struct sh_cmt_priv *p,
@@ -176,7 +175,6 @@ static DEFINE_RAW_SPINLOCK(sh_cmt_lock);
 
 static void sh_cmt_start_stop_ch(struct sh_cmt_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 */
@@ -184,9 +182,9 @@ static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
 	value = sh_cmt_read_cmstr(p);
 
 	if (start)
-		value |= 1 << cfg->timer_bit;
+		value |= 1 << p->timer_bit;
 	else
-		value &= ~(1 << cfg->timer_bit);
+		value &= ~(1 << p->timer_bit);
 
 	sh_cmt_write_cmstr(p, value);
 	raw_spin_unlock_irqrestore(&sh_cmt_lock, flags);
@@ -673,15 +671,93 @@ static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
 	return 0;
 }
 
-static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
+static const struct of_device_id of_sh_cmt_match[] = {
+	{ .compatible = "renesas,cmt-timer" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_sh_cmt_match);
+
+static const int sh_cmt_offset_multiplier[] = { 0x60, 0x10, 0x40, 0x40, 0x40 };
+#define CMT_MAX_CHANNELS	6
+
+static struct sh_timer_config *sh_cmt_parse_dt(struct device *dev)
+{
+	struct sh_timer_config *cfg;
+	struct device_node *np = dev->of_node;
+	u32 timer_id, 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,device-id", &timer_id)) {
+		dev_err(dev, "device id missing\n");
+		return NULL;
+	}
+	if (timer_id >= ARRAY_SIZE(sh_cmt_offset_multiplier)) {
+		dev_err(dev, "invalid device id\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 >= CMT_MAX_CHANNELS) {
+		dev_err(dev, "invalid channel id\n");
+		return NULL;
+	}
+
+	cfg->channel_offset = sh_cmt_offset_multiplier[timer_id] *
+							(channel_id + 1);
+	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_cmt_setup(struct sh_cmt_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;
 
 	memset(p, 0, sizeof(*p));
 	p->pdev = pdev;
+	p->channel_offset = cfg->channel_offset;
+	p->timer_bit = cfg->timer_bit;
 
 	if (!cfg) {
 		dev_err(&p->pdev->dev, "missing platform data\n");
@@ -777,7 +853,7 @@ err0:
 static int sh_cmt_probe(struct platform_device *pdev)
 {
 	struct sh_cmt_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)) {
@@ -785,6 +861,11 @@ static int sh_cmt_probe(struct platform_device *pdev)
 		pm_runtime_enable(&pdev->dev);
 	}
 
+	if (pdev->dev.of_node)
+		cfg = sh_cmt_parse_dt(&pdev->dev);
+	else
+		cfg = pdev->dev.platform_data;
+
 	if (p) {
 		dev_info(&pdev->dev, "kept as earlytimer\n");
 		goto out;
@@ -796,7 +877,7 @@ static int sh_cmt_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	ret = sh_cmt_setup(p, pdev);
+	ret = sh_cmt_setup(p, pdev, cfg);
 	if (ret) {
 		kfree(p);
 		pm_runtime_idle(&pdev->dev);
@@ -824,6 +905,7 @@ static struct platform_driver sh_cmt_device_driver = {
 	.remove		= sh_cmt_remove,
 	.driver		= {
 		.name	= "sh_cmt",
+		.of_match_table = of_match_ptr(of_sh_cmt_match),
 	}
 };
 
-- 
1.7.9.5