Subject: [PATCH 4/9] clk: sunxi: PLL2 support for sun4i, sun5i and sun7i

From: [email-masked] (Maxime Ripard)
Date: Sun, 3 Aug 2014 14:44:58 +0200

On Thu, Jul 31, 2014 at 06:28:07PM -0300, Emilio L?pez wrote:
> This patch adds support for PLL2 and derivates on sun4i, sun5i and
> sun7i SoCs. As this PLL is only used for audio and requires good
> accuracy, we only support two known good rates.
> 
> Signed-off-by: Emilio L?pez <[email-masked]>
> ---
> 
> Changes from RFC:
>  * Add support for A10 rev. A
>  * Document compatibles
>  * Use fixed factors
> 
>  Documentation/devicetree/bindings/clock/sunxi.txt |   2 +
>  drivers/clk/sunxi/Makefile                        |   1 +
>  drivers/clk/sunxi/clk-a10-pll2.c                  | 243 ++++++++++++++++++++++
>  3 files changed, 246 insertions(+)
>  create mode 100644 drivers/clk/sunxi/clk-a10-pll2.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
> index d3a5c3c..41ada31 100644
> --- a/Documentation/devicetree/bindings/clock/sunxi.txt
> +++ b/Documentation/devicetree/bindings/clock/sunxi.txt
> @@ -10,6 +10,8 @@ Required properties:
>  	"allwinner,sun4i-a10-pll1-clk" - for the main PLL clock and PLL4
>  	"allwinner,sun6i-a31-pll1-clk" - for the main PLL clock on A31
>  	"allwinner,sun8i-a23-pll1-clk" - for the main PLL clock on A23
> +	"allwinner,sun4i-a10-a-pll2-clk" - for the PLL2 clock on A10 rev. A
> +	"allwinner,sun4i-a10-b-pll2-clk" - for the PLL2 clock on A10 rev. B
>  	"allwinner,sun4i-a10-pll5-clk" - for the PLL5 clock
>  	"allwinner,sun4i-a10-pll6-clk" - for the PLL6 clock
>  	"allwinner,sun6i-a31-pll6-clk" - for the PLL6 clock on A31
> diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
> index 6850cba..dcd5709 100644
> --- a/drivers/clk/sunxi/Makefile
> +++ b/drivers/clk/sunxi/Makefile
> @@ -4,6 +4,7 @@
>  
>  obj-y += clk-sunxi.o clk-factors.o
>  obj-y += clk-a10-hosc.o
> +obj-y += clk-a10-pll2.o
>  obj-y += clk-a20-gmac.o
>  
>  obj-$(CONFIG_MFD_SUN6I_PRCM) += \
> diff --git a/drivers/clk/sunxi/clk-a10-pll2.c b/drivers/clk/sunxi/clk-a10-pll2.c
> new file mode 100644
> index 0000000..bcf7d0b
> --- /dev/null
> +++ b/drivers/clk/sunxi/clk-a10-pll2.c
> @@ -0,0 +1,243 @@
> +/*
> + * Copyright 2014 Emilio L?pez
> + *
> + * Emilio L?pez <[email-masked]>
> + *
> + * 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/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/slab.h>
> +
> +#define SUN4I_PLL2_ENABLE		31
> +#define SUN4I_PLL2_A_VCOBIAS		0
> +#define SUN4I_PLL2_A_VCOBIAS_MASK	0x1F
> +#define SUN4I_PLL2_A_N			7
> +#define SUN4I_PLL2_A_N_MASK		0x7F
> +#define SUN4I_PLL2_B_POST_DIV		26
> +#define SUN4I_PLL2_B_POST_DIV_MASK	0xF
> +#define SUN4I_PLL2_B_N			8
> +#define SUN4I_PLL2_B_N_MASK		0x7F
> +#define SUN4I_PLL2_B_PRE_DIV		0
> +#define SUN4I_PLL2_B_PRE_DIV_MASK	0x1F
> +
> +#define SUN4I_PLL2_OUTPUTS		4
> +
> +struct sun4i_pll2_clk {
> +	struct clk_hw hw;
> +	void __iomem *reg;
> +};
> +
> +static inline struct sun4i_pll2_clk *to_sun4i_pll2_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct sun4i_pll2_clk, hw);
> +}
> +
> +static unsigned long sun4i_pll2_recalc_rate_a(struct clk_hw *hw,
> +					      unsigned long parent_rate)
> +{
> +	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
> +	int vcobias, n;
> +	u32 val;
> +
> +	val = readl(clk->reg);
> +	vcobias = (val >> SUN4I_PLL2_A_VCOBIAS) & SUN4I_PLL2_A_VCOBIAS_MASK;
> +	n = (val >> SUN4I_PLL2_A_N) & SUN4I_PLL2_A_N_MASK;
> +
> +	if (vcobias == 10 && n == 94)
> +		return 22579200;
> +	else if (vcobias == 9 && n == 83)
> +		return 24576000;
> +
> +	/*
> +	 * Unfortunately we don't really have much documentation on how
> +	 * these factors relate mathematically
> +	 */
> +	return 0;
> +}
> +
> +static unsigned long sun4i_pll2_recalc_rate_b(struct clk_hw *hw,
> +					      unsigned long parent_rate)
> +{
> +	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
> +	int n, prediv, postdiv;
> +	u32 val;
> +
> +	val = readl(clk->reg);
> +	n = (val >> SUN4I_PLL2_B_N) & SUN4I_PLL2_B_N_MASK;
> +	prediv = (val >> SUN4I_PLL2_B_PRE_DIV) & SUN4I_PLL2_B_PRE_DIV_MASK;
> +	postdiv = (val >> SUN4I_PLL2_B_POST_DIV) & SUN4I_PLL2_B_POST_DIV_MASK;
> +
> +	/* 0 is a special case and means 1 */
> +	if (n == 0)
> +		n = 1;
> +	if (prediv == 0)
> +		prediv = 1;
> +	if (postdiv == 0)
> +		postdiv = 1;
> +
> +	return ((parent_rate * n) / prediv) / postdiv;
> +}
> +
> +static long sun4i_pll2_round_rate(struct clk_hw *hw, unsigned long rate,
> +				  unsigned long *parent_rate)
> +{
> +	/*
> +	 * There is only two interesting rates for the audio PLL, the
> +	 * rest isn't really usable due to accuracy concerns. Therefore,
> +	 * we specifically round to those rates here
> +	 */
> +	if (rate < 22579200)
> +		return -EINVAL;
> +
> +	if (rate >= 22579200 && rate < 24576000)
> +		return 22579200;
> +
> +	return 24576000;
> +}
> +
> +static int sun4i_pll2_set_rate_a(struct clk_hw *hw, unsigned long rate,
> +				 unsigned long parent_rate)
> +{
> +	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
> +	u32 val = readl(clk->reg);
> +
> +	val &= ~(SUN4I_PLL2_A_VCOBIAS_MASK << SUN4I_PLL2_A_VCOBIAS);
> +	val &= ~(SUN4I_PLL2_A_N_MASK << SUN4I_PLL2_A_N);
> +
> +	if (rate == 22579200)
> +		val |= (10 << SUN4I_PLL2_A_VCOBIAS) | (94 << SUN4I_PLL2_A_N);
> +	else if (rate == 24576000)
> +		val |= (9 << SUN4I_PLL2_A_VCOBIAS) | (83 << SUN4I_PLL2_A_N);
> +	else
> +		return -EINVAL;
> +
> +	writel(val, clk->reg);
> +
> +	return 0;
> +}
> +
> +static int sun4i_pll2_set_rate_b(struct clk_hw *hw, unsigned long rate,
> +				 unsigned long parent_rate)
> +{
> +	struct sun4i_pll2_clk *clk = to_sun4i_pll2_clk(hw);
> +	u32 val = readl(clk->reg);
> +
> +	val &= ~(SUN4I_PLL2_B_N_MASK << SUN4I_PLL2_B_N);
> +	val &= ~(SUN4I_PLL2_B_PRE_DIV_MASK << SUN4I_PLL2_B_PRE_DIV);
> +	val &= ~(SUN4I_PLL2_B_POST_DIV_MASK << SUN4I_PLL2_B_POST_DIV);
> +
> +	val |= (21 << SUN4I_PLL2_B_PRE_DIV) | (4 << SUN4I_PLL2_B_POST_DIV);
> +
> +	if (rate == 22579200)
> +		val |= (79 << SUN4I_PLL2_B_N);
> +	else if (rate == 24576000)
> +		val |= (86 << SUN4I_PLL2_B_N);
> +	else
> +		return -EINVAL;
> +
> +	writel(val, clk->reg);
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops sun4i_pll2_ops_a = {
> +	.recalc_rate = sun4i_pll2_recalc_rate_a,
> +	.round_rate = sun4i_pll2_round_rate,
> +	.set_rate = sun4i_pll2_set_rate_a,
> +};
> +
> +
> +static const struct clk_ops sun4i_pll2_ops_b = {
> +	.recalc_rate = sun4i_pll2_recalc_rate_b,
> +	.round_rate = sun4i_pll2_round_rate,
> +	.set_rate = sun4i_pll2_set_rate_b,
> +};
> +
> +static const struct of_device_id pll2_matches[] __initconst = {
> +	{ .compatible = "allwinner,sun4i-a10-a-pll2-clk", .data = &sun4i_pll2_ops_a },
> +	{ .compatible = "allwinner,sun4i-a10-b-pll2-clk", .data = &sun4i_pll2_ops_b },
> +	{ /* sentinel */ },
> +};
> +
> +static void __init sun4i_pll2_setup(struct device_node *np)
> +{
> +	const char *clk_name = np->name, *parent;
> +	const struct of_device_id *match;
> +	struct clk_onecell_data *clk_data;
> +	const struct clk_ops *pll2_ops;
> +	struct sun4i_pll2_clk *pll2;
> +	struct clk_gate *gate;
> +	struct clk **clks;
> +	void __iomem *reg;
> +
> +	/* Choose the correct ops for pll2 */
> +	match = of_match_node(pll2_matches, np);
> +	pll2_ops = match->data;
> +
> +	pll2 = kzalloc(sizeof(*pll2), GFP_KERNEL);
> +	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> +	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
> +	clks = kcalloc(SUN4I_PLL2_OUTPUTS, sizeof(*clks), GFP_KERNEL);
> +	if (!pll2 || !gate || !clk_data || !clks)
> +		goto free_mem;
> +
> +	reg = of_iomap(np, 0);
> +	parent = of_clk_get_parent_name(np, 0);
> +	of_property_read_string_index(np, "clock-output-names", 0, &clk_name);
> +
> +	pll2->reg = reg;
> +	gate->reg = reg;
> +	gate->bit_idx = SUN4I_PLL2_ENABLE;
> +
> +	/* PLL2, also known as PLL2x1 */
> +	of_property_read_string_index(np, "clock-output-names", 0, &clk_name);
> +	clks[0] = clk_register_composite(NULL, clk_name, &parent, 1, NULL, NULL,
> +					 &pll2->hw, pll2_ops,
> +					 &gate->hw, &clk_gate_ops, 0);
> +	WARN_ON(IS_ERR(clks[0]));
> +	clk_set_rate(clks[0], 22579200);
> +	parent = clk_name;
> +
> +	/* PLL2x2, 1/4 the rate of PLL2x8 */
> +	of_property_read_string_index(np, "clock-output-names", 1, &clk_name);
> +	clks[1] = clk_register_fixed_factor(NULL, clk_name, parent,
> +					    CLK_SET_RATE_PARENT, 2, 1);
> +	WARN_ON(IS_ERR(clks[1]));
> +
> +	/* PLL2x4, 1/2 the rate of PLL2x8 */
> +	of_property_read_string_index(np, "clock-output-names", 2, &clk_name);
> +	clks[2] = clk_register_fixed_factor(NULL, clk_name, parent,
> +					    CLK_SET_RATE_PARENT, 4, 1);
> +	WARN_ON(IS_ERR(clks[2]));
> +
> +	/* PLL2x8, double of PLL2 without the post divisor */
> +	of_property_read_string_index(np, "clock-output-names", 3, &clk_name);
> +	clks[3] = clk_register_fixed_factor(NULL, clk_name, parent,
> +					    CLK_SET_RATE_PARENT, 2 * 4, 1);

Why have you declared them here, instead of using fixed factors in the
DT directly, like we have done in the past?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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