Re: [PATCH] clk: mediatek: Export CPU mux clocks for CPU frequency control

[Pi-Cheng Chen <pi-cheng.chen@linaro.org>]

On Wed, Jul 15, 2015 at 02:38:46PM +0800, Pi-Cheng Chen wrote:
> From: "pi-cheng.chen" <pi-cheng.chen@linaro.org>
> 
> This patch adds CPU mux clocks which are used by Mediatek cpufreq driver
> for intermediate clock source switching.

Hi Mike and Stephen,

since the MT8173 cpufreq driver is likely going to be merged[1] and we still
need the CPU MUX clocks consumed by MT8173 cpufreq driver, may I have some
comments from you to get this patch moving forwards so that MT8173 cpufreq
driver could work completely?

Or the regmap supported basic clock type[2] is the prefered way?
Thanks.

Best Regards,
Pi-Cheng

[1] http://marc.info/?l=linux-pm&m=143850044118837&w=2
[2] http://marc.info/?l=linux-kernel&m=143835585905028&w=2

> 
> Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
> Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
> ---
> Changes in v4:
> - Address comments for v3
> - Rebase to the patch that adds 13mhz clock for MT8173[1]
> 
> Changes in v3:
> - Rebase to 4.2-rc1
> - Fix some issues of v2
> 
> Changes in v2:
> - Remove use of .determine_rate callback
> 
> [1] http://patchwork.kernerl.xyz/patch/6777041/
> ---
>  drivers/clk/mediatek/Makefile          |   2 +-
>  drivers/clk/mediatek/clk-cpumux.c      | 127 +++++++++++++++++++++++++++++++++
>  drivers/clk/mediatek/clk-cpumux.h      |  22 ++++++
>  drivers/clk/mediatek/clk-mt8173.c      |  23 ++++++
>  include/dt-bindings/clock/mt8173-clk.h |   4 +-
>  5 files changed, 176 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/clk/mediatek/clk-cpumux.c
>  create mode 100644 drivers/clk/mediatek/clk-cpumux.h
> 
> diff --git a/drivers/clk/mediatek/Makefile b/drivers/clk/mediatek/Makefile
> index 8e4b2a4..299917a 100644
> --- a/drivers/clk/mediatek/Makefile
> +++ b/drivers/clk/mediatek/Makefile
> @@ -1,4 +1,4 @@
> -obj-y += clk-mtk.o clk-pll.o clk-gate.o
> +obj-y += clk-mtk.o clk-pll.o clk-gate.o clk-cpumux.o
>  obj-$(CONFIG_RESET_CONTROLLER) += reset.o
>  obj-y += clk-mt8135.o
>  obj-y += clk-mt8173.o
> diff --git a/drivers/clk/mediatek/clk-cpumux.c b/drivers/clk/mediatek/clk-cpumux.c
> new file mode 100644
> index 0000000..fb04fe1
> --- /dev/null
> +++ b/drivers/clk/mediatek/clk-cpumux.c
> @@ -0,0 +1,127 @@
> +/*
> + * Copyright (c) 2015 Linaro Ltd.
> + * Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk-provider.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/slab.h>
> +
> +#include "clk-mtk.h"
> +#include "clk-cpumux.h"
> +
> +struct mtk_clk_cpumux {
> +	struct clk_hw	hw;
> +	struct regmap	*regmap;
> +	u32		reg;
> +	u32		mask;
> +	u8		shift;
> +};
> +
> +static inline struct mtk_clk_cpumux *to_clk_mux(struct clk_hw *_hw)
> +{
> +	return container_of(_hw, struct mtk_clk_cpumux, hw);
> +}
> +
> +static u8 clk_cpumux_get_parent(struct clk_hw *hw)
> +{
> +	struct mtk_clk_cpumux *mux = to_clk_mux(hw);
> +	int num_parents = __clk_get_num_parents(hw->clk);
> +	unsigned int val;
> +
> +	regmap_read(mux->regmap, mux->reg, &val);
> +
> +	val >>= mux->shift;
> +	val &= mux->mask;
> +
> +	if (val >= num_parents)
> +		return -EINVAL;
> +
> +	return val;
> +}
> +
> +static int clk_cpumux_set_parent(struct clk_hw *hw, u8 index)
> +{
> +	struct mtk_clk_cpumux *mux = to_clk_mux(hw);
> +	u32 mask, val;
> +
> +	val = index << mux->shift;
> +	mask = mux->mask << mux->shift;
> +
> +	return regmap_update_bits(mux->regmap, mux->reg, mask, val);
> +}
> +
> +static const struct clk_ops clk_cpumux_ops = {
> +	.get_parent = clk_cpumux_get_parent,
> +	.set_parent = clk_cpumux_set_parent,
> +};
> +
> +static struct clk __init *mtk_clk_register_cpumux(const struct mtk_composite *mux,
> +					   struct regmap *regmap)
> +{
> +	struct mtk_clk_cpumux *cpumux;
> +	struct clk *clk;
> +	struct clk_init_data init;
> +
> +	cpumux = kzalloc(sizeof(*cpumux), GFP_KERNEL);
> +	if (!cpumux)
> +		return ERR_PTR(-ENOMEM);
> +
> +	init.name = mux->name;
> +	init.ops = &clk_cpumux_ops;
> +	init.parent_names = mux->parent_names;
> +	init.num_parents = mux->num_parents;
> +	init.flags = mux->flags;
> +
> +	cpumux->reg = mux->mux_reg;
> +	cpumux->shift = mux->mux_shift;
> +	cpumux->mask = BIT(mux->mux_width) - 1;
> +	cpumux->regmap = regmap;
> +	cpumux->hw.init = &init;
> +
> +	clk = clk_register(NULL, &cpumux->hw);
> +	if (IS_ERR(clk))
> +		kfree(cpumux);
> +
> +	return clk;
> +}
> +
> +int __init mtk_clk_register_cpumuxes(struct device_node *node,
> +			      const struct mtk_composite *clks, int num,
> +			      struct clk_onecell_data *clk_data)
> +{
> +	int i;
> +	struct clk *clk;
> +	struct regmap *regmap;
> +
> +	regmap = syscon_node_to_regmap(node);
> +	if (IS_ERR(regmap)) {
> +		pr_err("Cannot find regmap for %s: %ld\n", node->full_name,
> +		       PTR_ERR(regmap));
> +		return PTR_ERR(regmap);
> +	}
> +
> +	for (i = 0; i < num; i++) {
> +		const struct mtk_composite *mux = &clks[i];
> +
> +		clk = mtk_clk_register_cpumux(mux, regmap);
> +		if (IS_ERR(clk)) {
> +			pr_err("Failed to register clk %s: %ld\n",
> +			       mux->name, PTR_ERR(clk));
> +			continue;
> +		}
> +
> +		clk_data->clks[mux->id] = clk;
> +	}
> +
> +	return 0;
> +}
> diff --git a/drivers/clk/mediatek/clk-cpumux.h b/drivers/clk/mediatek/clk-cpumux.h
> new file mode 100644
> index 0000000..52c769f
> --- /dev/null
> +++ b/drivers/clk/mediatek/clk-cpumux.h
> @@ -0,0 +1,22 @@
> +/*
> + * Copyright (c) 2015 Linaro Ltd.
> + * Author: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __DRV_CLK_CPUMUX_H
> +#define __DRV_CLK_CPUMUX_H
> +
> +int mtk_clk_register_cpumuxes(struct device_node *node,
> +			      const struct mtk_composite *clks, int num,
> +			      struct clk_onecell_data *clk_data);
> +
> +#endif /* __DRV_CLK_CPUMUX_H */
> diff --git a/drivers/clk/mediatek/clk-mt8173.c b/drivers/clk/mediatek/clk-mt8173.c
> index 540c5c3..053ca27 100644
> --- a/drivers/clk/mediatek/clk-mt8173.c
> +++ b/drivers/clk/mediatek/clk-mt8173.c
> @@ -19,6 +19,7 @@
>  
>  #include "clk-mtk.h"
>  #include "clk-gate.h"
> +#include "clk-cpumux.h"
>  
>  #include <dt-bindings/clock/mt8173-clk.h>
>  
> @@ -517,6 +518,25 @@ static const char * const i2s3_b_ck_parents[] __initconst = {
>  	"apll2_div5"
>  };
>  
> +static const char * const ca53_parents[] __initconst = {
> +	"clk26m",
> +	"armca7pll",
> +	"mainpll",
> +	"univpll"
> +};
> +
> +static const char * const ca57_parents[] __initconst = {
> +	"clk26m",
> +	"armca15pll",
> +	"mainpll",
> +	"univpll"
> +};
> +
> +static const struct mtk_composite cpu_muxes[] __initconst = {
> +	MUX(CLK_INFRA_CA53SEL, "infra_ca53_sel", ca53_parents, 0x0000, 0, 2),
> +	MUX(CLK_INFRA_CA57SEL, "infra_ca57_sel", ca57_parents, 0x0000, 2, 2),
> +};
> +
>  static const struct mtk_composite top_muxes[] __initconst = {
>  	/* CLK_CFG_0 */
>  	MUX(CLK_TOP_AXI_SEL, "axi_sel", axi_parents, 0x0040, 0, 3),
> @@ -743,6 +763,9 @@ static void __init mtk_infrasys_init(struct device_node *node)
>  						clk_data);
>  	mtk_clk_register_factors(infra_divs, ARRAY_SIZE(infra_divs), clk_data);
>  
> +	mtk_clk_register_cpumuxes(node, cpu_muxes, ARRAY_SIZE(cpu_muxes),
> +						clk_data);
> +
>  	r = of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
>  	if (r)
>  		pr_err("%s(): could not register clock provider: %d\n",
> diff --git a/include/dt-bindings/clock/mt8173-clk.h b/include/dt-bindings/clock/mt8173-clk.h
> index fa2a2bb..a17cbaa 100644
> --- a/include/dt-bindings/clock/mt8173-clk.h
> +++ b/include/dt-bindings/clock/mt8173-clk.h
> @@ -188,7 +188,9 @@
>  #define CLK_INFRA_PMICSPI		10
>  #define CLK_INFRA_PMICWRAP		11
>  #define CLK_INFRA_CLK_13M		12
> -#define CLK_INFRA_NR_CLK		13
> +#define CLK_INFRA_CA53SEL		13
> +#define CLK_INFRA_CA57SEL		14
> +#define CLK_INFRA_NR_CLK		15
>  
>  /* PERI_SYS */
>  
> -- 
> 1.9.1
>