[PATCH 3/5] clocksource: timer-cadence-ttc: Refactor common TTC resource setup

[Meher Thanmaiee]

Factor the TTC MMIO mapping and timer-width parsing in the timer probe
path into a helper.

As part of the refactor, switch the timer probe path from
devm_of_iomap() to devm_platform_ioremap_resource(). This is safe
because each Cadence TTC device tree node has a dedicated,
non-overlapping MMIO resource.

Also replace the hardcoded default timer width and channel stride with
TTC_DEFAULT_TIMER_WIDTH and TTC_CH_OFFSET, and switch to
device_property_read_u32() when reading timer-width.

This prepares the timer driver for later reuse of the common resource
setup by the PWM auxiliary-device path.

Signed-off-by: Meher Thanmaiee <meherthanmaiee.vanukuri@xxxxxxx>
---
 drivers/clocksource/timer-cadence-ttc.c | 49 ++++++++++++++++++---------------
 include/linux/timer-cadence-ttc.h       |  5 ++++
 2 files changed, 32 insertions(+), 22 deletions(-)

diff --git a/drivers/clocksource/timer-cadence-ttc.c b/drivers/clocksource/timer-cadence-ttc.c
index 75bc0af1fa9e..954a9b85a958 100644
--- a/drivers/clocksource/timer-cadence-ttc.c
+++ b/drivers/clocksource/timer-cadence-ttc.c
@@ -8,16 +8,16 @@
  */
 
 #include <linux/clk.h>
-#include <linux/interrupt.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
-#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
 #include <linux/of_irq.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
-#include <linux/slab.h>
+#include <linux/property.h>
 #include <linux/sched_clock.h>
-#include <linux/module.h>
-#include <linux/of_platform.h>
+#include <linux/slab.h>
 #include <linux/timer-cadence-ttc.h>
 
 /*
@@ -463,29 +463,36 @@ static int ttc_setup_clockevent(struct clk *clk,
 	return err;
 }
 
+static int ttc_init_common(struct platform_device *pdev,
+			   void __iomem **base, u32 *timer_width)
+{
+	*base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(*base))
+		return PTR_ERR(*base);
+
+	*timer_width = TTC_DEFAULT_TIMER_WIDTH;
+	device_property_read_u32(&pdev->dev, "timer-width", timer_width);
+
+	return 0;
+}
+
 static int ttc_timer_probe(struct platform_device *pdev)
 {
-	unsigned int irq;
+	struct device_node *timer = pdev->dev.of_node;
 	void __iomem *timer_baseaddr;
 	struct clk *clk_cs, *clk_ce;
 	static int initialized;
+	unsigned int irq;
+	u32 timer_width;
 	int clksel, ret;
-	u32 timer_width = 16;
-	struct device_node *timer = pdev->dev.of_node;
 
 	if (initialized)
 		return 0;
 
-	/*
-	 * Get the 1st Triple Timer Counter (TTC) block from the device tree
-	 * and use it. Note that the event timer uses the interrupt and it's the
-	 * 2nd TTC hence the irq_of_parse_and_map(,1)
-	 */
-	timer_baseaddr = devm_of_iomap(&pdev->dev, timer, 0, NULL);
-	if (IS_ERR(timer_baseaddr)) {
-		pr_err("ERROR: invalid timer base address\n");
-		return PTR_ERR(timer_baseaddr);
-	}
+	ret = ttc_init_common(pdev, &timer_baseaddr, &timer_width);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to map timer registers\n");
 
 	irq = irq_of_parse_and_map(timer, 1);
 	if (irq <= 0) {
@@ -493,8 +500,6 @@ static int ttc_timer_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	of_property_read_u32(timer, "timer-width", &timer_width);
-
 	clksel = readl_relaxed(timer_baseaddr + TTC_CLK_CNTRL_OFFSET);
 	clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK);
 	clk_cs = of_clk_get(timer, clksel);
@@ -503,7 +508,7 @@ static int ttc_timer_probe(struct platform_device *pdev)
 		return PTR_ERR(clk_cs);
 	}
 
-	clksel = readl_relaxed(timer_baseaddr + 4 + TTC_CLK_CNTRL_OFFSET);
+	clksel = readl_relaxed(timer_baseaddr + TTC_CH_OFFSET + TTC_CLK_CNTRL_OFFSET);
 	clksel = !!(clksel & TTC_CLK_CNTRL_CSRC_MASK);
 	clk_ce = of_clk_get(timer, clksel);
 	if (IS_ERR(clk_ce)) {
@@ -516,7 +521,7 @@ static int ttc_timer_probe(struct platform_device *pdev)
 	if (ret)
 		goto put_clk_ce;
 
-	ret = ttc_setup_clockevent(clk_ce, timer_baseaddr + 4, irq);
+	ret = ttc_setup_clockevent(clk_ce, timer_baseaddr + TTC_CH_OFFSET, irq);
 	if (ret)
 		goto put_clk_ce;
 
diff --git a/include/linux/timer-cadence-ttc.h b/include/linux/timer-cadence-ttc.h
index 4f2b85e0ff78..37ac775d6d50 100644
--- a/include/linux/timer-cadence-ttc.h
+++ b/include/linux/timer-cadence-ttc.h
@@ -11,6 +11,11 @@
 
 #include <linux/bits.h>
 
+#define TTC_DEFAULT_TIMER_WIDTH		16
+
+/* Per-channel register offset stride */
+#define TTC_CH_OFFSET			0x04
+
 /* Timer Register Offset Definitions of Timer 1 */
 #define TTC_CLK_CNTRL_OFFSET		0x00 /* Clock Control Reg, RW */
 #define TTC_CNT_CNTRL_OFFSET		0x0C /* Counter Control Reg, RW */

-- 
2.34.1