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

Maxime Ripard
2015-12-01T10:04:16Z

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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@csie.org>
> ---
> 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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