Re: [PATCH v4 1/5] clk: sunxi: Add CLK_OF_DECLARE support for sun8i-a23-apb0-clk driver

[Maxime Ripard]

Hi,

On Sun, Nov 29, 2015 at 11:03:06AM +0800, Chen-Yu Tsai wrote:
> The APBS clock on sun9i is the same as the APB0 clock on sun8i. With
> sun9i we are supporting the PRCM clocks by using CLK_OF_DECLARE,
> instead of through a PRCM mfd device and subdevices for each clock
> and reset control. As such we need a CLK_OF_DECLARE version of
> the sun8i-a23-apb0-clk driver.
> 
> Also, build it for sun9i/A80, and not just for configurations with
> MFD_SUN6I_PRCM enabled.
> 
> Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx>
> ---
>  drivers/clk/sunxi/Makefile         |  5 +--
>  drivers/clk/sunxi/clk-sun8i-apb0.c | 71 +++++++++++++++++++++++++++++++-------
>  2 files changed, 62 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
> index cb4c299214ce..c55d5cd1c0e5 100644
> --- a/drivers/clk/sunxi/Makefile
> +++ b/drivers/clk/sunxi/Makefile
> @@ -15,6 +15,7 @@ obj-y += clk-sun9i-core.o
>  obj-y += clk-sun9i-mmc.o
>  obj-y += clk-usb.o
>  
> +obj-$(CONFIG_MACH_SUN9I) += clk-sun8i-apb0.o
> +

So sun8i doesn't use it?

>  obj-$(CONFIG_MFD_SUN6I_PRCM) += \
> -	clk-sun6i-ar100.o clk-sun6i-apb0.o clk-sun6i-apb0-gates.o \
> -	clk-sun8i-apb0.o
> +	clk-sun6i-ar100.o clk-sun6i-apb0.o clk-sun6i-apb0-gates.o
> diff --git a/drivers/clk/sunxi/clk-sun8i-apb0.c b/drivers/clk/sunxi/clk-sun8i-apb0.c
> index 7ae5d2c2cde1..c1e2ac8f4b0d 100644
> --- a/drivers/clk/sunxi/clk-sun8i-apb0.c
> +++ b/drivers/clk/sunxi/clk-sun8i-apb0.c
> @@ -17,13 +17,68 @@
>  #include <linux/clk-provider.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/of_address.h>
>  #include <linux/platform_device.h>
>  
> +static struct clk *sun8i_a23_apb0_register(struct device_node *node,
> +					   void __iomem *reg)
> +{
> +	const char *clk_name = node->name;
> +	const char *clk_parent;
> +	struct clk *clk;
> +	int ret;
> +
> +	clk_parent = of_clk_get_parent_name(node, 0);
> +	if (!clk_parent)
> +		return ERR_PTR(-EINVAL);
> +
> +	of_property_read_string(node, "clock-output-names", &clk_name);
> +
> +	/* The A23 APB0 clock is a standard 2 bit wide divider clock */
> +	clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
> +				   0, 2, CLK_DIVIDER_POWER_OF_TWO, NULL);
> +	if (IS_ERR(clk))
> +		return clk;
> +
> +	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
> +	if (ret)
> +		goto err_unregister;
> +
> +	return clk;
> +
> +err_unregister:
> +	clk_unregister_divider(clk);
> +
> +	return ERR_PTR(ret);
> +}
> +
> +static void sun8i_a23_apb0_setup(struct device_node *node)
> +{
> +	void __iomem *reg;
> +	struct resource res;
> +	struct clk *clk;
> +
> +	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
> +	if (IS_ERR(reg))
> +		return;
> +
> +	clk = sun8i_a23_apb0_register(node, reg);
> +	if (IS_ERR(clk))
> +		goto err_unmap;
> +
> +	return;
> +
> +err_unmap:
> +	iounmap(reg);
> +	of_address_to_resource(node, 0, &res);
> +	release_mem_region(res.start, resource_size(&res));
> +}
> +CLK_OF_DECLARE(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
> +	       sun8i_a23_apb0_setup);
> +
>  static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> -	const char *clk_name = np->name;
> -	const char *clk_parent;
>  	struct resource *r;
>  	void __iomem *reg;
>  	struct clk *clk;
> @@ -33,19 +88,11 @@ static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
>  	if (IS_ERR(reg))
>  		return PTR_ERR(reg);
>  
> -	clk_parent = of_clk_get_parent_name(np, 0);
> -	if (!clk_parent)
> -		return -EINVAL;
> -
> -	of_property_read_string(np, "clock-output-names", &clk_name);
> -
> -	/* The A23 APB0 clock is a standard 2 bit wide divider clock */
> -	clk = clk_register_divider(&pdev->dev, clk_name, clk_parent, 0, reg,
> -				   0, 2, CLK_DIVIDER_POWER_OF_TWO, NULL);
> +	clk = sun8i_a23_apb0_register(np, reg);
>  	if (IS_ERR(clk))
>  		return PTR_ERR(clk);
>  
> -	return of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +	return 0;
>  }

Won't this probe twice now? First the CLK_OF_DECLARE will register a
clock, and then the device model will call probe a second time.

I guess then request_mem_region will catch it, but then you return an
error code, which is probably an error success, since the clock is
registered :)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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