Re: [PATCH v3 2/3] watchdog: orion: Use the reference clock on Armada 375 SoC

[Wim Van Sebroeck <wim@iguana.be>]

Hi Ezequiel,

You can add my: Acked-by: Wim Van Sebroeck <wim@iguana.be>

Kind regards,
Wim.

> The 25 MHz reference clock has better stability so its use is prefered 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.
> 
> Acked-by: Jason Cooper <jason@lakedaemon.net>
> Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
> ---
>  .../devicetree/bindings/watchdog/marvel.txt        | 13 +++++++
>  drivers/watchdog/orion_wdt.c                       | 42 +++++++++++++++++++++-
>  2 files changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/marvel.txt b/Documentation/devicetree/bindings/watchdog/marvel.txt
> index 97223fd..858ed92 100644
> --- a/Documentation/devicetree/bindings/watchdog/marvel.txt
> +++ b/Documentation/devicetree/bindings/watchdog/marvel.txt
> @@ -17,6 +17,18 @@ For "marvell,armada-375-wdt" and "marvell,armada-380-wdt":
>  - reg		: A third entry is mandatory and should contain the
>                    shared mask/unmask RSTOUT address.
>  
> +Clocks required for compatibles = "marvell,orion-wdt",
> +				  "marvell,armada-370-wdt":
> +- clocks : Must contain a single entry describing the clock input
> +
> +Clocks required for compatibles = "marvell,armada-xp-wdt"
> +				  "marvell,armada-375-wdt"
> +				  "marvell,armada-380-wdt":
> +- clocks : Must contain an entry for each entry in clock-names.
> +- clock-names : Must include the following entries:
> +  "nbclk" (L2/coherency fabric clock),
> +  "fixed" (Reference 25 MHz fixed-clock).
> +
>  Optional properties:
>  
>  - interrupts	: Contains the IRQ for watchdog expiration
> @@ -30,4 +42,5 @@ Example:
>  		interrupts = <3>;
>  		timeout-sec = <10>;
>  		status = "okay";
> +		clocks = <&gate_clk 7>;
>  	};
> diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.c
> index 00d0741..8cb1ff3 100644
> --- a/drivers/watchdog/orion_wdt.c
> +++ b/drivers/watchdog/orion_wdt.c
> @@ -114,6 +114,46 @@ static int armada370_wdt_clock_init(struct platform_device *pdev,
>  	return 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)) {
> +		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;
> +	}
> +
> +	/* Mandatory fallback for proper devicetree backward compatibility */
> +	dev->clk = clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(dev->clk))
> +		return PTR_ERR(dev->clk);
> +
> +	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;
> +
> +	return 0;
> +}
> +
>  static int armadaxp_wdt_clock_init(struct platform_device *pdev,
>  				   struct orion_watchdog *dev)
>  {
> @@ -394,7 +434,7 @@ static const struct orion_watchdog_data armada375_data = {
>  	.rstout_mask_bit = BIT(10),
>  	.wdt_enable_bit = BIT(8),
>  	.wdt_counter_offset = 0x34,
> -	.clock_init = armada370_wdt_clock_init,
> +	.clock_init = armada375_wdt_clock_init,
>  	.enabled = armada375_enabled,
>  	.start = armada375_start,
>  	.stop = armada375_stop,
> -- 
> 2.1.0
>