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

[Chen-Yu Tsai]

On Tue, Dec 1, 2015 at 6:04 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> 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?

Shit... I messed up. clk-sun8i-apb0.o should also be under
CONFIG_MFD_SUN6I_PRCM.

I'll send a new version of this patch. No need to keep spamming
people with the whole series.

>>  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.

AFAIK it will.

> 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 :)

Indeed. clk-mod0.c actually has a comment block explaining this.
I didn't want to repeat the whole thing though.

Regards
ChenYu
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