[PATCH 03/14] clk: Add {devm_}clk_hw_{register, unregister}() APIs

[Michael Turquette]

Quoting Stephen Boyd (2016-02-08 17:45:30)
> We've largely split the clk consumer and provider APIs along
> struct clk and struct clk_hw, but clk_register() still returns a
> struct clk pointer for each struct clk_hw that's registered.
> Eventually we'd like to only allocate struct clks when there's a
> user, because struct clk is per-user now, so clk_register() needs
> to change.
> 
> Let's add new APIs to register struct clk_hws, but this time
> we'll hide the struct clk from the caller by returning an int
> error code. Also add an unregistration API that takes the clk_hw
> structure that was passed to the registration API. This way
> provider drivers never have to deal with a struct clk pointer
> unless they're using the clk consumer APIs.
> 
> Signed-off-by: Stephen Boyd <sboyd at codeaurora.org>

Looks good to me.

Regards,
Mike

> ---
>  Documentation/driver-model/devres.txt |  1 +
>  drivers/clk/clk.c                     | 86 +++++++++++++++++++++++++++++++++++
>  include/linux/clk-provider.h          |  6 +++
>  3 files changed, 93 insertions(+)
> 
> diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
> index 831a5363f6be..600e30bf52c5 100644
> --- a/Documentation/driver-model/devres.txt
> +++ b/Documentation/driver-model/devres.txt
> @@ -236,6 +236,7 @@ certainly invest a bit more effort into libata core layer).
>  CLOCK
>    devm_clk_get()
>    devm_clk_put()
> +  devm_clk_hw_register()
>  
>  DMA
>    dmam_alloc_coherent()
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index b4db67a446c8..adaaead3639f 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -2613,6 +2613,22 @@ fail_out:
>  }
>  EXPORT_SYMBOL_GPL(clk_register);
>  
> +/**
> + * clk_hw_register - register a clk_hw and return an error code
> + * @dev: device that is registering this clock
> + * @hw: link to hardware-specific clock data
> + *
> + * clk_hw_register is the primary interface for populating the clock tree with
> + * new clock nodes. It returns an integer equal to zero indicating success or
> + * less than zero indicating failure. Drivers must test for an error code after
> + * calling clk_hw_register().
> + */
> +int clk_hw_register(struct device *dev, struct clk_hw *hw)
> +{
> +       return PTR_ERR_OR_ZERO(clk_register(dev, hw));
> +}
> +EXPORT_SYMBOL_GPL(clk_hw_register);
> +
>  /* Free memory allocated for a clock. */
>  static void __clk_release(struct kref *ref)
>  {
> @@ -2714,11 +2730,26 @@ void clk_unregister(struct clk *clk)
>  }
>  EXPORT_SYMBOL_GPL(clk_unregister);
>  
> +/**
> + * clk_hw_unregister - unregister a currently registered clk_hw
> + * @hw: hardware-specific clock data to unregister
> + */
> +void clk_hw_unregister(struct clk_hw *hw)
> +{
> +       clk_unregister(hw->clk);
> +}
> +EXPORT_SYMBOL_GPL(clk_hw_unregister);
> +
>  static void devm_clk_release(struct device *dev, void *res)
>  {
>         clk_unregister(*(struct clk **)res);
>  }
>  
> +static void devm_clk_hw_release(struct device *dev, void *res)
> +{
> +       clk_hw_unregister(*(struct clk_hw **)res);
> +}
> +
>  /**
>   * devm_clk_register - resource managed clk_register()
>   * @dev: device that is registering this clock
> @@ -2749,6 +2780,36 @@ struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
>  }
>  EXPORT_SYMBOL_GPL(devm_clk_register);
>  
> +/**
> + * devm_clk_hw_register - resource managed clk_hw_register()
> + * @dev: device that is registering this clock
> + * @hw: link to hardware-specific clock data
> + *
> + * Managed clk_hw_register(). Clocks returned from this function are
> + * automatically clk_hw_unregister()ed on driver detach. See clk_hw_register()
> + * for more information.
> + */
> +int devm_clk_hw_register(struct device *dev, struct clk_hw *hw)
> +{
> +       struct clk_hw **hwp;
> +       int ret;
> +
> +       hwp = devres_alloc(devm_clk_hw_release, sizeof(*hwp), GFP_KERNEL);
> +       if (!hwp)
> +               return -ENOMEM;
> +
> +       ret = clk_hw_register(dev, hw);
> +       if (!ret) {
> +               *hwp = hw;
> +               devres_add(dev, hwp);
> +       } else {
> +               devres_free(hwp);
> +       }
> +
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_clk_hw_register);
> +
>  static int devm_clk_match(struct device *dev, void *res, void *data)
>  {
>         struct clk *c = res;
> @@ -2757,6 +2818,15 @@ static int devm_clk_match(struct device *dev, void *res, void *data)
>         return c == data;
>  }
>  
> +static int devm_clk_hw_match(struct device *dev, void *res, void *data)
> +{
> +       struct clk_hw *hw = res;
> +
> +       if (WARN_ON(!hw))
> +               return 0;
> +       return hw == data;
> +}
> +
>  /**
>   * devm_clk_unregister - resource managed clk_unregister()
>   * @clk: clock to unregister
> @@ -2771,6 +2841,22 @@ void devm_clk_unregister(struct device *dev, struct clk *clk)
>  }
>  EXPORT_SYMBOL_GPL(devm_clk_unregister);
>  
> +/**
> + * devm_clk_hw_unregister - resource managed clk_hw_unregister()
> + * @dev: device that is unregistering the hardware-specific clock data
> + * @hw: link to hardware-specific clock data
> + *
> + * Unregister a clk_hw registered with devm_clk_hw_register(). Normally
> + * this function will not need to be called and the resource management
> + * code will ensure that the resource is freed.
> + */
> +void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw)
> +{
> +       WARN_ON(devres_release(dev, devm_clk_hw_release, devm_clk_hw_match,
> +                               hw));
> +}
> +EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);
> +
>  /*
>   * clkdev helpers
>   */
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 1143e38555a4..abc16d77fb62 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -639,9 +639,15 @@ void of_gpio_mux_clk_setup(struct device_node *node);
>  struct clk *clk_register(struct device *dev, struct clk_hw *hw);
>  struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw);
>  
> +int __must_check clk_hw_register(struct device *dev, struct clk_hw *hw);
> +int __must_check devm_clk_hw_register(struct device *dev, struct clk_hw *hw);
> +
>  void clk_unregister(struct clk *clk);
>  void devm_clk_unregister(struct device *dev, struct clk *clk);
>  
> +void clk_hw_unregister(struct clk_hw *hw);
> +void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw);
> +
>  /* helper functions */
>  const char *__clk_get_name(const struct clk *clk);
>  const char *clk_hw_get_name(const struct clk_hw *hw);
> -- 
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> a Linux Foundation Collaborative Project
>