Re: [PATCH 1/7] clk: rockchip: add support for phase inverters

[Stephen Boyd <sboyd@codeaurora.org>]

On 07/05, Heiko Stuebner wrote:
> Most Rockchip socs have optional phase inverters connected to some
> clocks that move the clock-phase by 180 degrees.
> While not having any actual influence on the rate, the inverter
> provides its own simple recalc_rate callback as relying on the
> fallback in the framework is for "lazy developers" according
> to the documentation in the code.
> 
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> ---
>  drivers/clk/rockchip/Makefile       |   1 +
>  drivers/clk/rockchip/clk-inverter.c | 116 ++++++++++++++++++++++++++++++++++++
>  drivers/clk/rockchip/clk.c          |   7 +++
>  drivers/clk/rockchip/clk.h          |  20 +++++++
>  4 files changed, 144 insertions(+)
>  create mode 100644 drivers/clk/rockchip/clk-inverter.c
> 
> diff --git a/drivers/clk/rockchip/Makefile b/drivers/clk/rockchip/Makefile
> index 2714097..fd71c7d 100644
> --- a/drivers/clk/rockchip/Makefile
> +++ b/drivers/clk/rockchip/Makefile
> @@ -6,6 +6,7 @@ obj-y	+= clk-rockchip.o
>  obj-y	+= clk.o
>  obj-y	+= clk-pll.o
>  obj-y	+= clk-cpu.o
> +obj-y	+= clk-inverter.o
>  obj-y	+= clk-mmc-phase.o
>  obj-$(CONFIG_RESET_CONTROLLER)	+= softrst.o
>  
> diff --git a/drivers/clk/rockchip/clk-inverter.c b/drivers/clk/rockchip/clk-inverter.c
> new file mode 100644
> index 0000000..8054fdb
> --- /dev/null
> +++ b/drivers/clk/rockchip/clk-inverter.c
> @@ -0,0 +1,116 @@
> +/*
> + * Copyright 2015 Heiko Stuebner <heiko@sntech.de>
> + *
> + * 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; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * 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/slab.h>
> +#include <linux/clk-provider.h>
> +#include <linux/io.h>
> +#include <linux/spinlock.h>
> +#include <linux/kernel.h>
> +#include "clk.h"
> +
> +struct rockchip_inv_clock {
> +	struct clk_hw	hw;
> +	void __iomem	*reg;
> +	int		shift;
> +	int		flags;
> +	spinlock_t	*lock;
> +};
> +
> +#define to_inv_clock(_hw) container_of(_hw, struct rockchip_inv_clock, hw)
> +
> +#define INVERTER_MASK 0x1
> +
> +static int rockchip_inv_get_phase(struct clk_hw *hw)
> +{
> +	struct rockchip_inv_clock *inv_clock = to_inv_clock(hw);
> +	u32 val;
> +
> +	val = readl(inv_clock->reg) >> inv_clock->shift;
> +	val &= INVERTER_MASK;
> +	return val ? 180 : 0;
> +}
> +
> +static int rockchip_inv_set_phase(struct clk_hw *hw, int degrees)
> +{
> +	struct rockchip_inv_clock *inv_clock = to_inv_clock(hw);
> +	u32 val;
> +
> +	if (degrees % 180 == 0) {
> +		val = !!degrees;
> +	} else {
> +		pr_err("%s: unsupported phase %d for %s\n",
> +		       __func__, degrees, __clk_get_name(hw->clk));
> +		return -EINVAL;
> +	}
> +
> +	if (inv_clock->flags & ROCKCHIP_INVERTER_HIWORD_MASK) {
> +		writel(HIWORD_UPDATE(val, INVERTER_MASK, inv_clock->shift),
> +		       inv_clock->reg);
> +	} else {
> +		unsigned long flags;
> +		u32 reg;
> +
> +		spin_lock_irqsave(inv_clock->lock, flags);
> +
> +		reg = readl(inv_clock->reg);
> +		reg &= ~BIT(inv_clock->shift);
> +		reg |= val;
> +		writel(reg, inv_clock->reg);
> +
> +		spin_unlock_irqrestore(inv_clock->lock, flags);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops rockchip_inv_clk_ops = {
> +	.get_phase	= rockchip_inv_get_phase,
> +	.set_phase	= rockchip_inv_set_phase,
> +};
> +
> +struct clk *rockchip_clk_register_inverter(const char *name,
> +				const char *const *parent_names, u8 num_parents,
> +				void __iomem *reg, int shift, int flags,
> +				spinlock_t *lock)
> +{
> +	struct clk_init_data init;
> +	struct rockchip_inv_clock *inv_clock;
> +	struct clk *clk;
> +
> +	inv_clock = kmalloc(sizeof(*inv_clock), GFP_KERNEL);
> +	if (!inv_clock)
> +		return NULL;
> +
> +	init.name = name;
> +	init.num_parents = num_parents;
> +	init.flags = CLK_SET_RATE_PARENT;
> +	init.parent_names = parent_names;
> +	init.ops = &rockchip_inv_clk_ops;
> +
> +	inv_clock->hw.init = &init;
> +	inv_clock->reg = reg;
> +	inv_clock->shift = shift;
> +	inv_clock->flags = flags;
> +	inv_clock->lock = lock;
> +
> +	clk = clk_register(NULL, &inv_clock->hw);
> +	if (IS_ERR(clk))
> +		goto err_free;
> +
> +	return clk;
> +
> +err_free:
> +	kfree(inv_clock);
> +	return NULL;
> +}
> diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
> index 052b94d..2493881 100644
> --- a/drivers/clk/rockchip/clk.c
> +++ b/drivers/clk/rockchip/clk.c
> @@ -277,6 +277,13 @@ void __init rockchip_clk_register_branches(
>  				list->div_shift
>  			);
>  			break;
> +		case branch_inverter:
> +			clk = rockchip_clk_register_inverter(
> +				list->name, list->parent_names,
> +				list->num_parents,
> +				reg_base + list->muxdiv_offset,
> +				list->div_shift, list->div_flags, &clk_lock);
> +			break;
>  		}
>  
>  		/* none of the cases above matched */
> diff --git a/drivers/clk/rockchip/clk.h b/drivers/clk/rockchip/clk.h
> index 501f02e..b72dad0 100644
> --- a/drivers/clk/rockchip/clk.h
> +++ b/drivers/clk/rockchip/clk.h
> @@ -182,6 +182,13 @@ struct clk *rockchip_clk_register_mmc(const char *name,
>  				const char *const *parent_names, u8 num_parents,
>  				void __iomem *reg, int shift);
>  
> +#define ROCKCHIP_INVERTER_HIWORD_MASK	BIT(0)
> +
> +struct clk *rockchip_clk_register_inverter(const char *name,
> +				const char *const *parent_names, u8 num_parents,
> +				void __iomem *reg, int shift, int flags,
> +				spinlock_t *lock);
> +
>  #define PNAME(x) static const char *const x[] __initconst

Also this seems to be based on clk-next/v4.2-rc1, so I've moved
the clk-rk3368 branch forward to v4.2-rc1.

>  
>  enum rockchip_clk_branch_type {
> @@ -191,6 +198,7 @@ enum rockchip_clk_branch_type {
>  	branch_fraction_divider,
>  	branch_gate,
>  	branch_mmc,
> +	branch_inverter,
>  };
>  
>  struct rockchip_clk_branch {
> @@ -414,6 +422,18 @@ struct rockchip_clk_branch {
>  		.div_shift	= shift,			\
>  	}
>  
> +#define INVERTER(_id, cname, pname, io, is, if)			\
> +	{							\
> +		.id		= _id,				\
> +		.branch_type	= branch_inverter,		\
> +		.name		= cname,			\
> +		.parent_names	= (const char *[]){ pname },	\
> +		.num_parents	= 1,				\
> +		.muxdiv_offset	= io,				\
> +		.div_shift	= is,				\
> +		.div_flags	= if,				\
> +	}
> +
>  void rockchip_clk_init(struct device_node *np, void __iomem *base,
>  		       unsigned long nr_clks);
>  struct regmap *rockchip_clk_get_grf(void);
> -- 
> 2.1.4
> 

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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