On Mon, Dec 07, 2015 at 09:46:24PM +0800, Chen-Yu Tsai wrote: > On Mon, Dec 7, 2015 at 5:36 PM, Maxime Ripard > <maxime.rip...@free-electrons.com> wrote: > > Hi, > > > > On Thu, Dec 03, 2015 at 03:05:30PM +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 <w...@csie.org> > >> --- > >> > >> Changes since v4: > >> > >> - Keep building clk-sun8i-apb0 for SUN6I_MFD_PRCM. > >> > >> - Add an error message and comment for when of_io_request_and_map() > >> fails. of_io_request_and_map() merges a bunch of errors into -EINVAL, > >> so this might not be the best approach. But I think having an error > >> message when we know something is wrong (-EBUSY, -ENOMEM) is better. > >> > >> --- > >> drivers/clk/sunxi/Makefile | 1 + > >> drivers/clk/sunxi/clk-sun8i-apb0.c | 80 > >> ++++++++++++++++++++++++++++++++------ > >> 2 files changed, 69 insertions(+), 12 deletions(-) > >> > >> diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile > >> index 103efab05ca8..ccf21ba3b6b0 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-$(CONFIG_MACH_SUN9I) += clk-sun8i-apb0.o > >> obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-cpus.o > >> > >> obj-$(CONFIG_MFD_SUN6I_PRCM) += \ > >> diff --git a/drivers/clk/sunxi/clk-sun8i-apb0.c > >> b/drivers/clk/sunxi/clk-sun8i-apb0.c > >> index 7ae5d2c2cde1..7ba61103a6f5 100644 > >> --- a/drivers/clk/sunxi/clk-sun8i-apb0.c > >> +++ b/drivers/clk/sunxi/clk-sun8i-apb0.c > >> @@ -17,13 +17,77 @@ > >> #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)) { > >> + /* > >> + * This happens with clk nodes instantiated through mfd, > >> + * as those do not have their resources assigned in the > >> + * device tree. Do not print an error in this case. > >> + */ > >> + if (PTR_ERR(reg) != -EINVAL) > >> + pr_err("Could not get registers for a23-apb0-clk\n"); > > > > This is not the only case you have to take into account. > > > > There's also the case when you have a regular clock (and by regular I > > mean that is not in the PRCM) that will be probed by the > > CLK_OF_DECLARE mechanism and then later by the device model. > > > > In such a case, the second of_io_request_and_map will fail, and you > > will have an error returned that you do not ignore at the moment. > > Right. It will return -EBUSY. But ignoring it and returning 0 is telling > the driver core that the device successfully binded. I think this is > wrong.
Well, technically, it is already bound. > Normal clocks should be in the "clocks" node, and wouldn't be probed a > second time through the device model, would it? Am I missing something? Hmmm, that's true. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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