Re: [PATCH v2 04/15] ARM: shmobile: r8a7778: common clock framework CPG driver

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Ulrich,

Thank you for the patch.

On Monday 09 February 2015 17:02:32 Ulrich Hecht wrote:
> Driver for the r8a7778's clocks that depend on the mode bits.
> 
> Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
> ---
>  .../bindings/clock/renesas,r8a7778-cpg-clocks.txt  |  24 ++++
>  drivers/clk/shmobile/Makefile                      |   1 +
>  drivers/clk/shmobile/clk-r8a7778.c                 | 142 ++++++++++++++++++
>  include/linux/clk/shmobile.h                       |   1 +
>  4 files changed, 168 insertions(+)
>  create mode 100644
> Documentation/devicetree/bindings/clock/renesas,r8a7778-cpg-clocks.txt
> create mode 100644 drivers/clk/shmobile/clk-r8a7778.c
> 
> diff --git
> a/Documentation/devicetree/bindings/clock/renesas,r8a7778-cpg-clocks.txt
> b/Documentation/devicetree/bindings/clock/renesas,r8a7778-cpg-clocks.txt
> new file mode 100644
> index 0000000..c9a9544
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/renesas,r8a7778-cpg-clocks.txt
> @@ -0,0 +1,24 @@
> +* Renesas R8A7778 Clock Pulse Generator (CPG)
> +
> +The CPG generates core clocks for the R8A7778. It includes two PLLs and
> +several fixed ratio dividers
> +
> +Required Properties:
> +
> +  - compatible: Must be "renesas,r8a7778-cpg-clocks"
> +  - reg: Base address and length of the memory resource used by the CPG
> +  - #clock-cells: Must be 1
> +  - clock-output-names: The names of the clocks. Supported clocks are
> +    "extal", "plla", "pllb", "b", "out", "p", "s", and "s1".

You should remove "extal" here and in the example below now that is has been 
removed from the driver, and add a clocks property that references the 
external clock.

> +
> +
> +Example
> +-------
> +
> +	cpg_clocks: cpg_clocks@ffc80000 {
> +		compatible = "renesas,r8a7778-cpg-clocks";
> +		reg = <0xffc80000 0x80>;
> +		#clock-cells = <1>;
> +		clock-output-names = "extal", "plla", "pllb", "b",
> +				     "out", "p", "s", "s1";
> +	};
> diff --git a/drivers/clk/shmobile/Makefile b/drivers/clk/shmobile/Makefile
> index 0689d7f..97c71c8 100644
> --- a/drivers/clk/shmobile/Makefile
> +++ b/drivers/clk/shmobile/Makefile
> @@ -2,6 +2,7 @@ obj-$(CONFIG_ARCH_EMEV2)		+= clk-emev2.o
>  obj-$(CONFIG_ARCH_R7S72100)		+= clk-rz.o
>  obj-$(CONFIG_ARCH_R8A73A4)		+= clk-r8a73a4.o
>  obj-$(CONFIG_ARCH_R8A7740)		+= clk-r8a7740.o
> +obj-$(CONFIG_ARCH_R8A7778)		+= clk-r8a7778.o
>  obj-$(CONFIG_ARCH_R8A7779)		+= clk-r8a7779.o
>  obj-$(CONFIG_ARCH_R8A7790)		+= clk-rcar-gen2.o
>  obj-$(CONFIG_ARCH_R8A7791)		+= clk-rcar-gen2.o
> diff --git a/drivers/clk/shmobile/clk-r8a7778.c
> b/drivers/clk/shmobile/clk-r8a7778.c new file mode 100644
> index 0000000..19ce008
> --- /dev/null
> +++ b/drivers/clk/shmobile/clk-r8a7778.c
> @@ -0,0 +1,142 @@
> +/*
> + * r8a7778 Core CPG Clocks
> + *
> + * Copyright (C) 2014  Ulrich Hecht
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; version 2 of the License.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/shmobile.h>
> +#include <linux/of_address.h>
> +
> +struct r8a7778_cpg {
> +	struct clk_onecell_data data;
> +	spinlock_t lock;
> +	void __iomem *reg;
> +};
> +
> +/* PLL multipliers per bits 11, 12, and 18 of MODEMR */
> +struct {
> +	unsigned long plla_mult;
> +	unsigned long pllb_mult;
> +} r8a7778_rates[] __initdata = {
> +	[0] = { 21, 21},
> +	[1] = { 24, 24},
> +	[2] = { 28, 28},
> +	[3] = { 32, 32},
> +	[5] = { 24, 21},
> +	[6] = { 28, 21},
> +	[7] = { 32, 24},

How about s/}/ }/ ?

> +};
> +
> +/* Clock dividers per bits 1 and 2 of MODEMR */
> +struct {
> +	const char *name;
> +	unsigned int div[4];
> +} r8a7778_divs[6] __initdata = {
> +	{ "b",   { 12, 12, 16, 18 } },
> +	{ "out", { 12, 12, 16, 18 } },
> +	{ "p",   { 16, 12, 16, 12 } },
> +	{ "s",   { 4,  3,  4,  3  } },
> +	{ "s1",  { 8,  6,  8,  6  } },
> +	{ NULL },
> +};
> +
> +static u32 cpg_mode_rates __initdata;
> +static u32 cpg_mode_divs __initdata;
> +
> +static struct clk * __init
> +r8a7778_cpg_register_clock(struct device_node *np, struct r8a7778_cpg *cpg,
> +			     const char *name)
> +{
> +	if (!strcmp(name, "plla")) {
> +		return clk_register_fixed_factor(NULL, "plla", "extal", 0,

You should now use of_clk_get_parent_name(np, 0) instead of the hardcoded 
"extal" name.

> +			r8a7778_rates[cpg_mode_rates].plla_mult, 1);
> +	} else if (!strcmp(name, "pllb")) {
> +		return clk_register_fixed_factor(NULL, "pllb", "extal", 0,
> +			r8a7778_rates[cpg_mode_rates].pllb_mult, 1);

Same here.

> +	} else {
> +		unsigned int i;
> +
> +		for (i = 0; r8a7778_divs[i].name; i++) {

As mentioned as a comment to v1, you could use i < ARRAY_SIZE(r8a7778_divs) 
here and avoid the NULL entry at the end of the array. If you don't think 
that's a good idea, no problem, but please state so in a reply otherwise I 
can't know whether you've decided to ignore my comment or just forgot to 
address it.

> +			if (!strcmp(name, r8a7778_divs[i].name)) {
> +				return clk_register_fixed_factor(NULL,
> +					r8a7778_divs[i].name,
> +					"plla", 0, 1,
> +					r8a7778_divs[i].div[cpg_mode_divs]);
> +			}
> +		}
> +	}
> +
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +
> +static void __init r8a7778_cpg_clocks_init(struct device_node *np)
> +{
> +	struct r8a7778_cpg *cpg;
> +	struct clk **clks;
> +	unsigned int i;
> +	int num_clks;
> +
> +	num_clks = of_property_count_strings(np, "clock-output-names");
> +	if (num_clks < 0) {
> +		pr_err("%s: failed to count clocks\n", __func__);
> +		return;
> +	}
> +
> +	cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
> +	clks = kcalloc(num_clks, sizeof(*clks), GFP_KERNEL);
> +	if (cpg = NULL || clks = NULL) {
> +		/* We're leaking memory on purpose, there's no point in cleaning
> +		 * up as the system won't boot anyway.
> +		 */
> +		return;
> +	}
> +
> +	spin_lock_init(&cpg->lock);
> +
> +	cpg->data.clks = clks;
> +	cpg->data.clk_num = num_clks;
> +
> +	cpg->reg = of_iomap(np, 0);
> +	if (WARN_ON(cpg->reg = NULL))
> +		return;
> +
> +	for (i = 0; i < num_clks; ++i) {
> +		const char *name;
> +		struct clk *clk;
> +
> +		of_property_read_string_index(np, "clock-output-names", i,
> +					      &name);
> +
> +		clk = r8a7778_cpg_register_clock(np, cpg, name);
> +		if (IS_ERR(clk))
> +			pr_err("%s: failed to register %s %s clock (%ld)\n",
> +			       __func__, np->name, name, PTR_ERR(clk));
> +		else
> +			cpg->data.clks[i] = clk;
> +	}
> +
> +	of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
> +}
> +
> +CLK_OF_DECLARE(r8a7778_cpg_clks, "renesas,r8a7778-cpg-clocks",
> +	       r8a7778_cpg_clocks_init);
> +
> +void __init r8a7778_clocks_init(u32 mode)
> +{
> +	if (!(mode & BIT(19)))
> +		BUG();

Same for BUG_ON() here.

> +	cpg_mode_rates = (!!(mode & BIT(18)) << 2) |
> +			 (!!(mode & BIT(12)) << 1) |
> +			 (!!(mode & BIT(11)));
> +	cpg_mode_divs = (!!(mode & BIT(2)) << 1) |
> +			(!!(mode & BIT(1)));
> +
> +	of_clk_init(NULL);
> +}
> diff --git a/include/linux/clk/shmobile.h b/include/linux/clk/shmobile.h
> index 9f8a140..63a8159 100644
> --- a/include/linux/clk/shmobile.h
> +++ b/include/linux/clk/shmobile.h
> @@ -16,6 +16,7 @@
> 
>  #include <linux/types.h>
> 
> +void r8a7778_clocks_init(u32 mode);
>  void r8a7779_clocks_init(u32 mode);
>  void rcar_gen2_clocks_init(u32 mode);

-- 
Regards,

Laurent Pinchart