linux-kernel - Re: [PATCH] rtc: sun6i: Add support for the external oscillator gate

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Message-ID: <20170824143645.3pwfgnvhhqh3m2d6@piout.net>
Date:   Thu, 24 Aug 2017 16:36:45 +0200
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:     Chen-Yu Tsai <wens@...e.org>, linux-rtc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rtc: sun6i: Add support for the external oscillator gate

Hi,

On 24/08/2017 at 14:18:54 +0200, Maxime Ripard wrote:
> The RTC can output its 32kHz clock outside of the SoC, for example to clock
> a WiFi chip.
> 
> Create a new clock that other devices will be able to retrieve, while
> maintaining the DT stability by providing a default name for that clock if
> clock-output-names doesn't list one.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@...e-electrons.com>
> ---
>  .../devicetree/bindings/rtc/sun6i-rtc.txt          |  4 ++--
>  drivers/rtc/rtc-sun6i.c                            | 24 +++++++++++++++++++---
>  2 files changed, 23 insertions(+), 5 deletions(-)
> 

It doesn't apply cleanly, can you rebase on top of -next?

> diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
> index 945934918b71..d5e26d313f62 100644
> --- a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
> +++ b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt
> @@ -10,7 +10,7 @@ Required properties:
>  
>  Required properties for new device trees
>  - clocks	: phandle to the 32kHz external oscillator
> -- clock-output-names : name of the LOSC clock created
> +- clock-output-names : names of the LOSC and its external output clocks created
>  - #clock-cells  : must be equals to 1. The RTC provides two clocks: the
>  		  LOSC and its external output, with index 0 and 1
>  		  respectively.
> @@ -21,7 +21,7 @@ rtc: rtc@...00000 {
>  	compatible = "allwinner,sun6i-a31-rtc";
>  	reg = <0x01f00000 0x54>;
>  	interrupts = <0 40 4>, <0 41 4>;
> -	clock-output-names = "osc32k";
> +	clock-output-names = "osc32k", "osc32k-out";
>  	clocks = <&ext_osc32k>;
>  	#clock-cells = <1>;
>  };
> diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
> index 39cbc1238b92..d4a6ddbfd872 100644
> --- a/drivers/rtc/rtc-sun6i.c
> +++ b/drivers/rtc/rtc-sun6i.c
> @@ -73,6 +73,9 @@
>  #define SUN6I_ALARM_CONFIG			0x0050
>  #define SUN6I_ALARM_CONFIG_WAKEUP		BIT(0)
>  
> +#define SUN6I_LOSC_OUT_GATING			0x0060
> +#define SUN6I_LOSC_OUT_GATING_EN		BIT(0)
> +
>  /*
>   * Get date values
>   */
> @@ -125,6 +128,7 @@ struct sun6i_rtc_dev {
>  	struct clk_hw hw;
>  	struct clk_hw *int_osc;
>  	struct clk *losc;
> +	struct clk *ext_losc;
>  
>  	spinlock_t lock;
>  };
> @@ -188,6 +192,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
>  	struct clk_init_data init = {
>  		.ops		= &sun6i_rtc_osc_ops,
>  	};
> +	const char *clkout_name = "osc32k-out";
>  	const char *parents[2];
>  
>  	rtc = kzalloc(sizeof(*rtc), GFP_KERNEL);
> @@ -195,7 +200,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
>  		return;
>  	spin_lock_init(&rtc->lock);
>  
> -	clk_data = kzalloc(sizeof(*clk_data) + sizeof(*clk_data->hws),
> +	clk_data = kzalloc(sizeof(*clk_data) + (sizeof(*clk_data->hws) * 2),
>  			   GFP_KERNEL);
>  	if (!clk_data)
>  		return;
> @@ -235,7 +240,8 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
>  
>  	init.parent_names = parents;
>  	init.num_parents = of_clk_get_parent_count(node) + 1;
> -	of_property_read_string(node, "clock-output-names", &init.name);
> +	of_property_read_string_index(node, "clock-output-names", 0,
> +				      &init.name);
>  
>  	rtc->losc = clk_register(NULL, &rtc->hw);
>  	if (IS_ERR(rtc->losc)) {
> @@ -243,8 +249,20 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
>  		return;
>  	}
>  
> -	clk_data->num = 1;
> +	of_property_read_string_index(node, "clock-output-names", 1,
> +				      &clkout_name);
> +	rtc->ext_losc = clk_register_gate(NULL, clkout_name, rtc->hw.init->name,
> +					  0, rtc->base + SUN6I_LOSC_OUT_GATING,
> +					  SUN6I_LOSC_OUT_GATING_EN, 0,
> +					  &rtc->lock);
> +	if (IS_ERR(rtc->ext_losc)) {
> +		pr_crit("Couldn't register the LOSC external gate\n");
> +		return;
> +	}
> +
> +	clk_data->num = 2;
>  	clk_data->hws[0] = &rtc->hw;
> +	clk_data->hws[1] = __clk_get_hw(rtc->ext_losc);
>  	of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
>  }
>  CLK_OF_DECLARE_DRIVER(sun6i_rtc_clk, "allwinner,sun6i-a31-rtc",
> -- 
> 2.13.5
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com