Make Armada 375 use the reference clock when possible

This commit makes sure the timer clock is prepared and enabled before retrieving its rate.

Acked-by Gregory CLEMENT <[email protected]>

Reviewed-by Thomas Petazzoni <[email protected]>

Signed-off-by Ezequiel Garcia <[email protected]>

---
 drivers/clocksource/time-armada-370-xp.c | 2 ++
 1 file changed, 2 insertions(+)

Dear Ezequiel Garcia,

It's really nitpicking, but I find the usage of empty newlines rather unfortunate in the below function.

drivers/watchdog/orion_wdt.c static int armada370_wdt_clock_init(struct platform_device *pdev, · line 124

Quoted 9 lines

drivers/watchdog/orion_wdt.c +8 -0

+static int armada375_wdt_clock_init(struct platform_device *pdev,
+				    struct orion_watchdog *dev)
+{
+	int ret;
+
+	dev->clk = of_clk_get_by_name(pdev->dev.of_node, "fixed");
+	if (!IS_ERR(dev->clk)) {
+

This empty new line seems not needed.

drivers/watchdog/orion_wdt.c static int armada370_wdt_clock_init(struct platform_device *pdev, · line 135

Quoted 11 lines

drivers/watchdog/orion_wdt.c +11 -0

+		ret = clk_prepare_enable(dev->clk);
+		if (ret) {
+			clk_put(dev->clk);
+			return ret;
+		}
+
+		atomic_io_modify(dev->reg + TIMER_CTRL,
+				WDT_AXP_FIXED_ENABLE_BIT,
+				WDT_AXP_FIXED_ENABLE_BIT);
+		dev->clk_rate = clk_get_rate(dev->clk);
+		return 0;

But one empty new line before the return would be good.

drivers/watchdog/orion_wdt.c static int armada370_wdt_clock_init(struct platform_device *pdev, · line 141

Quoted 6 lines

drivers/watchdog/orion_wdt.c +6 -0

+	}
+
+	/* Mandatory fallback for proper devicetree backward compatibility */
+	dev->clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);

An empty newline would be good here as well.

drivers/watchdog/orion_wdt.c static int armada370_wdt_clock_init(struct platform_device *pdev, · line 151

Quoted 10 lines

drivers/watchdog/orion_wdt.c +10 -0

+	ret = clk_prepare_enable(dev->clk);
+	if (ret) {
+		clk_put(dev->clk);
+		return ret;
+	}
+
+	atomic_io_modify(dev->reg + TIMER_CTRL,
+			WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT),
+			WDT_A370_RATIO_MASK(WDT_A370_RATIO_SHIFT));
+	dev->clk_rate = clk_get_rate(dev->clk) / WDT_A370_RATIO;

And here.

With this fixed:

Reviewed-by Thomas Petazzoni <[email protected]>

Signature · 3 lines

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

The 25 MHz reference clock has better stability so its use is preferred over the core clock. Change the Armada 375 clock initialization to use this reference clock. To ensure the driver is compatible with an old devicetree, also provide a fallback path which will silently return to the previous behavior.

While here, add the clock specification to the binding documentation.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 .../devicetree/bindings/watchdog/marvel.txt        | 13 +++++++
 drivers/watchdog/orion_wdt.c                       | 40 +++++++++++++++++++++-
 2 files changed, 52 insertions(+), 1 deletion(-)

The 25 MHz reference clock has better stability so its use is preferred over the core clock.

This commit takes advantage of the already introduced Armada 375 devicetree compatible string and adds a new timer initialization. If available, the timer will use the reference clock (named as 'fixed'). Otherwise, it falls back to the previous behavior.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 .../bindings/timer/marvell,armada-370-xp-timer.txt |  9 ++++---
 drivers/clocksource/time-armada-370-xp.c           | 28 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

The 25 MHz reference clock has better stability so its use is preferred over the core clock.

This commit takes advantage of the already introduced Armada 375 devicetree compatible string and adds a new timer initialization. If available, the timer will use the reference clock (named as 'fixed'). Otherwise, it falls back to the previous behavior.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 .../bindings/timer/marvell,armada-370-xp-timer.txt |  9 ++++---
 drivers/clocksource/time-armada-370-xp.c           | 28 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

The 25 MHz reference clock has better stability so its use is preferred over the core clock.

This commit takes advantage of the already introduced Armada 375 devicetree compatible string and adds a new timer initialization. If available, the timer will use the reference clock (named as 'fixed'). Otherwise, it falls back to the previous behavior.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 .../bindings/timer/marvell,armada-370-xp-timer.txt |  9 ++++---
 drivers/clocksource/time-armada-370-xp.c           | 28 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

Now that the timer and watchdog drivers support the Armada 375 usage of the reference clock, we can enable it in the devicetree.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 arch/arm/boot/dts/armada-375.dtsi | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Now that the timer and watchdog drivers support the Armada 375 usage of the reference clock, we can enable it in the devicetree.

Signed-off-by Ezequiel Garcia <[email protected]>

---
 arch/arm/boot/dts/armada-375.dtsi | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Ezequiel Garcia (4):
clocksource: armada-370-xp: Add missing clock enable
watchdog: orion: Use the reference clock on Armada 375 SoC
clocksource: armada-370-xp: Use the reference clock on A375 SoC
ARM: mvebu: Enable the reference clock for timer and watchdog on
Armada 375 SoC

 .../bindings/timer/marvell,armada-370-xp-timer.txt |  9 +++--
 .../devicetree/bindings/watchdog/marvel.txt        | 13 +++++++
 arch/arm/boot/dts/armada-375.dtsi                  | 12 +++++--
 drivers/clocksource/time-armada-370-xp.c           | 30 ++++++++++++++++
 drivers/watchdog/orion_wdt.c                       | 40 +++++++++++++++++++++-
 5 files changed, 98 insertions(+), 6 deletions(-)