[U-Boot] [PATCH v2 1/2] clk: clk-uclass: Add post binding for CLK uclass

[Yang, Wenyou]

> -----Original Message-----
> From: sjg at google.com [mailto:sjg at google.com] On Behalf Of Simon Glass
> Sent: 2016年6月10日 8:34
> To: Yang, Wenyou <Wenyou.Yang at atmel.com>
> Cc: U-Boot Mailing List <u-boot at lists.denx.de>; Andreas Bießmann
> <andreas at biessmann.org>
> Subject: Re: [PATCH v2 1/2] clk: clk-uclass: Add post binding for CLK uclass
> 
> Hi Wenyou,
> 
> On 7 June 2016 at 01:11, Wenyou Yang <wenyou.yang at atmel.com> wrote:
> > Add post binding support for CLK uclass to recursively bind its
> > children as clk devices.
> >
> > Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
> > ---
> >
> > Changes in v2: None
> >
> >  drivers/clk/clk-uclass.c | 51
> > ++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 51 insertions(+)
> 
> 
> Can you please explain what this is for? We would normally call
> dm_scan_fdt_node() for this, but it seems that you are specifically to create
> drivers for things with no compatible strings.

Yes, for pheriph32ck node have a lot of child nodes with no compatible strings.
This patch purpose is to bind these children nodes. Otherwise these nodes will not be bound.

For example,

---8<----
	ahb {
		apb {
			pmc: pmc at f0014000 {
				
				[snip]				

				periph32ck {
					compatible = "atmel,at91sam9x5-clk-peripheral";
					#address-cells = <1>;
					#size-cells = <0>;
					clocks = <&h32ck>;

					macb0_clk: macb0_clk {
						#clock-cells = <0>;
						reg = <5>;
						atmel,clk-output-range = <0 83000000>;
					};

					[snip]

					pioA_clk: pioA_clk {
						#clock-cells = <0>;
						reg = <18>;
						atmel,clk-output-range = <0 83000000>;
					};

					[snip]

					spi0_clk: spi0_clk {
						#clock-cells = <0>;
						reg = <33>;
						atmel,clk-output-range = <0 83000000>;
					};

					[snip]
				};
			};

			spi0: spi at f8000000 {
				compatible = "atmel,at91rm9200-spi";
				reg = <0xf8000000 0x100>;
				clocks = <&spi0_clk>;
				clock-names = "spi_clk";
				#address-cells = <1>;
				#size-cells = <0>;
				status = "disabled";
			};

			macb0: ethernet at f8008000 {
				compatible = "cdns,macb";
				reg = <0xf8008000 0x1000>;
				#address-cells = <1>;
				#size-cells = <0>;
				clocks = <&macb0_clk>, <&macb0_clk>;
				clock-names = "hclk", "pclk";
				status = "disabled";
			};

			[snip]			

			pioA: gpio at fc038000 {
				compatible = "atmel,sama5d2-gpio";
				reg = <0xfc038000 0x600>;
				clocks = <&pioA_clk>;
				gpio-controller;
				#gpio-cells = <2>;

				pinctrl {
					compatible = "atmel,sama5d2-pinctrl";
				};
			};
		};
	};

---->8-----

> 
> >
> > diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c index
> > b483c1e..ee568e4 100644
> > --- a/drivers/clk/clk-uclass.c
> > +++ b/drivers/clk/clk-uclass.c
> > @@ -106,7 +106,58 @@ int clk_get_by_index(struct udevice *dev, int
> > index, struct udevice **clk_devp)  }  #endif
> >
> > +/**
> > + * clk_post-bind() - post binding for CLK uclass
> > + * Recursively bind its children as clk devices.
> > + *
> > + * @dev: clk device
> > + * @return: 0 on success, or negative error code on failure  */
> > +static int clk_post_bind(struct udevice *dev) {
> > +       const void *fdt = gd->fdt_blob;
> > +       int offset = dev->of_offset;
> > +       bool pre_reloc_only = !(gd->flags & GD_FLG_RELOC);
> > +       const char *name;
> > +       int ret;
> > +
> > +       for (offset = fdt_first_subnode(fdt, offset);
> > +            offset > 0;
> > +            offset = fdt_next_subnode(fdt, offset)) {
> > +               if (pre_reloc_only &&
> > +                   !fdt_getprop(fdt, offset, "u-boot,dm-pre-reloc", NULL))
> > +                       continue;
> > +               /*
> > +                * If this node has "compatible" property, this is not a clk
> > +                * node, but a normal device. skip.
> > +                */
> > +               fdt_get_property(fdt, offset, "compatible", &ret);
> > +               if (ret >= 0)
> > +                       continue;
> > +
> > +               if (ret != -FDT_ERR_NOTFOUND)
> > +                       return ret;
> > +
> > +               name = fdt_get_name(fdt, offset, NULL);
> > +               if (!name)
> > +                       return -EINVAL;
> > +
> > +               ret = device_bind_driver_to_node(dev, "clk", name,
> > +                                                offset, NULL);
> > +               if (ret)
> > +                       return ret;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> >  UCLASS_DRIVER(clk) = {
> >         .id             = UCLASS_CLK,
> > +       .post_bind      = clk_post_bind,
> >         .name           = "clk",
> >  };
> > +
> > +U_BOOT_DRIVER(clk_generic) = {
> > +       .id     = UCLASS_CLK,
> > +       .name   = "clk",
> > +};
> > --
> > 2.7.4
> >
> 
> Regards,
> Simon