Date: Fri, 4 Oct 2013 15:17:56 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Mike Turquette <mturquette@linaro.org>,
        Russell King <linux@arm.linux.org.uk>,
        Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>,
        Grant Likely <grant.likely@linaro.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
        Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] clk: provide public clk_is_enabled function
Message-ID: <20131004131756.GD23809@lunn.ch>
References: <1380881310-24345-1-git-send-email-sebastian.hesselbarth@gmail.com>
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On Fri, Oct 04, 2013 at 12:08:30PM +0200, Sebastian Hesselbarth wrote:
> To determine if a clk has been previously enabled, provide a public
> clk_is_enabled function. This is especially helpful to check the state
> of clk-gate without actually changing the state of the gate.
> 
> Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

Tested-by: Andrew Lunn <andrew@lunn.ch>

	   Andrew


> ---
> Cc: Mike Turquette <mturquette@linaro.org>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Andrew Lunn <andrew@lunn.ch>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/clk/clk.c   |   18 ++++++++++++++++++
>  include/linux/clk.h |   13 +++++++++++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index a004769..26698d3 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -929,6 +929,24 @@ int clk_enable(struct clk *clk)
>  EXPORT_SYMBOL_GPL(clk_enable);
>  
>  /**
> + * clk_is_enabled - return the enabled state of a clk
> + * @clk: the clk whose enabled state gets returned
> + *
> + * Returns true if the clock is enabled, false otherwise.
> + */
> +bool clk_is_enabled(struct clk *clk)
> +{
> +	bool is_en;
> +
> +	clk_prepare_lock();
> +	is_en = __clk_is_enabled(clk);
> +	clk_prepare_unlock();
> +
> +	return is_en;
> +}
> +EXPORT_SYMBOL_GPL(clk_is_enabled);
> +
> +/**
>   * __clk_round_rate - round the given rate for a clk
>   * @clk: round the rate of this clock
>   * @rate: the rate which is to be rounded
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 9a6d045..8cbf2f7 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -187,6 +187,14 @@ int clk_enable(struct clk *clk);
>  void clk_disable(struct clk *clk);
>  
>  /**
> + * clk_is_enabled - return the enabled state of a clk
> + * @clk: the clk whose enabled state gets returned
> + *
> + * Returns true if the clock is enabled, false otherwise.
> + */
> +bool clk_is_enabled(struct clk *clk);
> +
> +/**
>   * clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
>   *		  This is only valid once the clock source has been enabled.
>   * @clk: clock source
> @@ -299,6 +307,11 @@ static inline int clk_enable(struct clk *clk)
>  
>  static inline void clk_disable(struct clk *clk) {}
>  
> +static inline bool clk_is_enabled(struct clk *clk)
> +{
> +	return false;
> +}
> +
>  static inline unsigned long clk_get_rate(struct clk *clk)
>  {
>  	return 0;
> -- 
> 1.7.10.4
> 
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