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

Maxime Ripard
2015-12-01T12:50:32Z

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On Tue, Dec 01, 2015 at 07:54:06PM +0800, Chen-Yu Tsai wrote:
> On Tue, Dec 1, 2015 at 6:04 PM, Maxime Ripard
> <maxime.ripard@free-electrons.com> 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@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?
>
> 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.

Ok.

> >> 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.

I guess, we can simply return 0 if of_io_request_and_map returns
EBUSY, since it would simply mean that we already probed.

Maxime

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

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