Message-ID: <20170623153958.v4xatscf4v5oueoh@piout.net>
Date:   Fri, 23 Jun 2017 17:39:58 +0200
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Quentin Schulz <quentin.schulz@...e-electrons.com>
Cc:     mturquette@...libre.com, sboyd@...eaurora.org, robh+dt@...nel.org,
        mark.rutland@....com, nicolas.ferre@...rochip.com,
        linux@...linux.org.uk, boris.brezillon@...e-electrons.com,
        lgirdwood@...il.com, broonie@...nel.org, perex@...ex.cz,
        tiwai@...e.com, Nicolas Ferre <nicolas.ferre@...el.com>,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        alsa-devel@...a-project.org, thomas.petazzoni@...e-electrons.com
Subject: Re: [PATCH 2/6] clk: at91: add audio pll clock driver

Hi,

On 23/06/2017 at 11:00:55 +0200, Quentin Schulz wrote:
> From: Nicolas Ferre <nicolas.ferre@...el.com>
> 
> This new clock driver set allows to have a fractional divided clock that
> would generate a precise clock particularly suitable for audio
> applications.
> 
> The main audio pll clock has two children clocks: one that is connected
> to the PMC, the other that can directly drive a pad. As these two routes
> have different enable bits and different dividers and divider formula,
> they are handled by two different drivers. Each of them could modify the
> rate of the main audio pll parent.
> The main audio pll clock can output 620MHz to 700MHz.
> 
> Signed-off-by: Nicolas Ferre <nicolas.ferre@...el.com>
> Signed-off-by: Quentin Schulz <quentin.schulz@...e-electrons.com>
> ---
>  .../devicetree/bindings/clock/at91-clock.txt       |  10 +
>  arch/arm/mach-at91/Kconfig                         |   4 +
>  drivers/clk/at91/Makefile                          |   2 +
>  drivers/clk/at91/clk-audio-pll-pad.c               | 204 ++++++++++++++++++
>  drivers/clk/at91/clk-audio-pll-pmc.c               | 175 +++++++++++++++
>  drivers/clk/at91/clk-audio-pll.c                   | 237 +++++++++++++++++++++
>  include/linux/clk/at91_pmc.h                       |  25 +++
>  sound/soc/atmel/atmel-classd.c                     |  20 +-

This should definitively go in a separate patch.

>  8 files changed, 658 insertions(+), 19 deletions(-)
>  create mode 100644 drivers/clk/at91/clk-audio-pll-pad.c
>  create mode 100644 drivers/clk/at91/clk-audio-pll-pmc.c
>  create mode 100644 drivers/clk/at91/clk-audio-pll.c
> 
> diff --git a/Documentation/devicetree/bindings/clock/at91-clock.txt b/Documentation/devicetree/bindings/clock/at91-clock.txt
> index 5f3ad65daf69..51c259a92d02 100644
> --- a/Documentation/devicetree/bindings/clock/at91-clock.txt
> +++ b/Documentation/devicetree/bindings/clock/at91-clock.txt
> @@ -81,6 +81,16 @@ Required properties:
>  	"atmel,sama5d2-clk-generated":
>  		at91 generated clock
>  
> +	"atmel,sama5d2-clk-audio-pll-frac":
> +		at91 audio fractional pll
> +
> +	"atmel,sama5d2-clk-audio-pll-pad":
> +		at91 audio pll CLK_AUDIO output pin
> +
> +	"atmel,sama5d2-clk-audio-pll-pmc"
> +		at91 audio pll output on AUDIOPLLCLK that feeds the PMC
> +		and can be used by peripheral clock or generic clock
> +
>  Required properties for SCKC node:
>  - reg : defines the IO memory reserved for the SCKC.
>  - #size-cells : shall be 0 (reg is used to encode clk id).
> diff --git a/arch/arm/mach-at91/Kconfig b/arch/arm/mach-at91/Kconfig
> index d735e5fc4772..9ae14d59a9ce 100644
> --- a/arch/arm/mach-at91/Kconfig
> +++ b/arch/arm/mach-at91/Kconfig
> @@ -26,6 +26,7 @@ config SOC_SAMA5D2
>  	select HAVE_AT91_USB_CLK
>  	select HAVE_AT91_H32MX
>  	select HAVE_AT91_GENERATED_CLK
> +	select HAVE_AT91_AUDIO_PLL
>  	select PINCTRL_AT91PIO4
>  	help
>  	  Select this if ou are using one of Atmel's SAMA5D2 family SoC.
> @@ -125,6 +126,9 @@ config HAVE_AT91_H32MX
>  config HAVE_AT91_GENERATED_CLK
>  	bool
>  
> +config HAVE_AT91_AUDIO_PLL
> +	bool
> +
>  config SOC_SAM_V4_V5
>  	bool
>  
> diff --git a/drivers/clk/at91/Makefile b/drivers/clk/at91/Makefile
> index 13e67bd35cff..c9353d17763a 100644
> --- a/drivers/clk/at91/Makefile
> +++ b/drivers/clk/at91/Makefile
> @@ -6,6 +6,8 @@ obj-y += pmc.o sckc.o
>  obj-y += clk-slow.o clk-main.o clk-pll.o clk-plldiv.o clk-master.o
>  obj-y += clk-system.o clk-peripheral.o clk-programmable.o
>  
> +obj-$(CONFIG_HAVE_AT91_AUDIO_PLL)	+= clk-audio-pll.o
> +obj-$(CONFIG_HAVE_AT91_AUDIO_PLL)	+= clk-audio-pll-pmc.o clk-audio-pll-pad.o
>  obj-$(CONFIG_HAVE_AT91_UTMI)		+= clk-utmi.o
>  obj-$(CONFIG_HAVE_AT91_USB_CLK)		+= clk-usb.o
>  obj-$(CONFIG_HAVE_AT91_SMD)		+= clk-smd.o
> diff --git a/drivers/clk/at91/clk-audio-pll-pad.c b/drivers/clk/at91/clk-audio-pll-pad.c
> new file mode 100644
> index 000000000000..a60ce47b82c6
> --- /dev/null
> +++ b/drivers/clk/at91/clk-audio-pll-pad.c
> @@ -0,0 +1,204 @@
> +/*
> + *  Copyright (C) 2016 Atmel Corporation,
> + *                     Nicolas Ferre <nicolas.ferre@...el.com>
> + *
> + * 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.
> + *
> + */
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/at91_pmc.h>
> +#include <linux/of.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +
> +#include "pmc.h"
> +
> +/*
> + * DOC: PAD output for fractional PLL clock for audio
> + *
> + * Traits of this clock:
> + * enable - clk_enable writes divisors and enables PAD output
> + * rate - rate is adjustable.
> + *        clk->rate = parent->rate / (qdaudio * div))
> + * parent - fixed parent.  No clk_set_parent support
> + */
> +
> +#define AUDIO_PLL_QDPAD(qd, div)	((AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV(qd) & \
> +					  AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MASK) | \
> +					 (AT91_PMC_AUDIO_PLL_QDPAD_DIV(div) & \
> +					  AT91_PMC_AUDIO_PLL_QDPAD_DIV_MASK))
> +
> +struct clk_audio_pad {
> +	struct clk_hw hw;
> +	struct regmap *regmap;
> +	u8 qdaudio;
> +	u8 div;
> +};
> +
> +#define to_clk_audio_pad(hw) container_of(hw, struct clk_audio_pad, hw)
> +
> +static int clk_audio_pll_pad_enable(struct clk_hw *hw)
> +{
> +	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
> +
> +	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL1,
> +			   AT91_PMC_AUDIO_PLL_QDPAD_MASK,
> +			   AUDIO_PLL_QDPAD(apad_ck->qdaudio, apad_ck->div));
> +	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PADEN, AT91_PMC_AUDIO_PLL_PADEN);
> +
> +	return 0;
> +}
> +
> +static void clk_audio_pll_pad_disable(struct clk_hw *hw)
> +{
> +	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
> +
> +	regmap_update_bits(apad_ck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PADEN, 0);
> +}
> +
> +static unsigned long clk_audio_pll_pad_recalc_rate(struct clk_hw *hw,
> +						   unsigned long parent_rate)
> +{
> +	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
> +	unsigned long apad_rate = 0;
> +
> +	if (apad_ck->qdaudio && apad_ck->div)
> +		apad_rate = parent_rate / (apad_ck->qdaudio * apad_ck->div);
> +
> +	pr_debug("A PLL/PAD: %s, apad_rate = %lu (div = %u, qdaudio = %u)\n",
> +		 __func__, apad_rate, apad_ck->div, apad_ck->qdaudio);
> +
> +	return apad_rate;
> +}
> +
> +static long clk_audio_pll_pad_round_rate(struct clk_hw *hw, unsigned long rate,
> +					 unsigned long *parent_rate)
> +{
> +	struct clk_hw *pclk = clk_hw_get_parent(hw);
> +	long best_rate = -EINVAL;
> +	unsigned long best_parent_rate;
> +	unsigned long tmp_qd;
> +	u32 div;
> +	long tmp_rate;
> +	int tmp_diff;
> +	int best_diff = -1;
> +
> +	pr_debug("A PLL/PAD: %s, rate = %lu (parent_rate = %lu)\n", __func__,
> +		 rate, *parent_rate);
> +
> +	/*
> +	 * Rate divisor is actually made of two different divisors, multiplied
> +	 * between themselves before dividing the rate.
> +	 * tmp_qd goes from 1 to 31 and div is either 2 or 3.
> +	 * In order to avoid testing twice the rate divisor (e.g. divisor 12 can
> +	 * be found with (tmp_qd, div) = (2, 6) or (3, 4)), we remove any loop
> +	 * for a rate divisor when div is 2 and tmp_qd is a multiple of 3.
> +	 * We cannot inverse it (condition div is 3 and tmp_qd is even) or we
> +	 * would miss some rate divisor that aren't reachable with div being 2
> +	 * (e.g. rate divisor 90 is made with div = 3 and tmp_qd = 30, thus
> +	 * tmp_qd is even so we skip it because we think div 2 could make this
> +	 * rate divisor which isn't possible since tmp_qd has to be <= 31).
> +	 */
> +	for (tmp_qd = 1; tmp_qd < AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MAX; tmp_qd++)
> +		for (div = 2; div <= 3; div++) {
> +			if (div == 2 && tmp_qd % 3 == 0)
> +				continue;
> +
> +			best_parent_rate = clk_hw_round_rate(pclk,
> +							rate * tmp_qd * div);
> +			tmp_rate = best_parent_rate / (div * tmp_qd);
> +			tmp_diff = abs(rate - tmp_rate);
> +
> +			if (best_diff < 0 || best_diff > tmp_diff) {
> +				*parent_rate = best_parent_rate;
> +				best_rate = tmp_rate;
> +				best_diff = tmp_diff;
> +			}
> +		}
> +
> +	pr_debug("A PLL/PAD: %s, best_rate = %ld, best_parent_rate = %lu\n",
> +		 __func__, best_rate, best_parent_rate);
> +
> +	return best_rate;
> +}
> +
> +static int clk_audio_pll_pad_set_rate(struct clk_hw *hw, unsigned long rate,
> +				      unsigned long parent_rate)
> +{
> +	struct clk_audio_pad *apad_ck = to_clk_audio_pad(hw);
> +	u8 tmp_div;
> +
> +	pr_debug("A PLL/PAD: %s, rate = %lu (parent_rate = %lu)\n", __func__,
> +		 rate, parent_rate);
> +
> +	if (!rate)
> +		return -EINVAL;
> +
> +	tmp_div = parent_rate / rate;
> +	if (tmp_div % 3 == 0) {
> +		apad_ck->qdaudio = tmp_div / 3;
> +		apad_ck->div = 3;
> +	} else {
> +		apad_ck->qdaudio = tmp_div / 2;
> +		apad_ck->div = 2;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops audio_pll_pad_ops = {
> +	.enable = clk_audio_pll_pad_enable,
> +	.disable = clk_audio_pll_pad_disable,
> +	.recalc_rate = clk_audio_pll_pad_recalc_rate,
> +	.round_rate = clk_audio_pll_pad_round_rate,
> +	.set_rate = clk_audio_pll_pad_set_rate,
> +};
> +
> +static void __init of_sama5d2_clk_audio_pll_pad_setup(struct device_node *np)
> +{
> +	struct clk_audio_pad *apad_ck;
> +	struct clk_init_data init;
> +	struct regmap *regmap;
> +	const char *parent_name;
> +	const char *name = np->name;
> +	int ret;
> +
> +	parent_name = of_clk_get_parent_name(np, 0);
> +
> +	of_property_read_string(np, "clock-output-names", &name);
> +
> +	regmap = syscon_node_to_regmap(of_get_parent(np));
> +	if (IS_ERR(regmap))
> +		return;
> +
> +	apad_ck = kzalloc(sizeof(*apad_ck), GFP_KERNEL);
> +	if (!apad_ck)
> +		return;
> +
> +	init.name = name;
> +	init.ops = &audio_pll_pad_ops;
> +	init.parent_names = (parent_name ? &parent_name : NULL);
> +	init.num_parents = 1;
> +	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
> +		CLK_SET_RATE_PARENT;
> +
> +	apad_ck->hw.init = &init;
> +	apad_ck->regmap = regmap;
> +
> +	ret = clk_hw_register(NULL, &apad_ck->hw);
> +	if (ret)
> +		kfree(apad_ck);
> +	else
> +		of_clk_add_hw_provider(np, of_clk_hw_simple_get, &apad_ck->hw);
> +}
> +
> +CLK_OF_DECLARE(of_sama5d2_clk_audio_pll_pad_setup,
> +	       "atmel,sama5d2-clk-audio-pll-pad",
> +	       of_sama5d2_clk_audio_pll_pad_setup);
> diff --git a/drivers/clk/at91/clk-audio-pll-pmc.c b/drivers/clk/at91/clk-audio-pll-pmc.c
> new file mode 100644
> index 000000000000..208d0b59eb4e
> --- /dev/null
> +++ b/drivers/clk/at91/clk-audio-pll-pmc.c
> @@ -0,0 +1,175 @@
> +/*
> + *  Copyright (C) 2016 Atmel Corporation,
> + *                     Nicolas Ferre <nicolas.ferre@...el.com>
> + *
> + * 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.
> + *
> + */
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/at91_pmc.h>
> +#include <linux/of.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +
> +#include "pmc.h"
> +
> +/*
> + * DOC: PMC output for fractional PLL clock for audio
> + *
> + * Traits of this clock:
> + * enable - clk_enable writes qdpmc, and enables PMC output
> + * rate - rate is adjustable.
> + *        clk->rate = parent->rate / (qdpmc + 1)
> + * parent - fixed parent.  No clk_set_parent support
> + */
> +
> +#define AUDIO_PLL_FOUT_MIN		620000000
> +#define AUDIO_PLL_FOUT_MAX		700000000
> +#define AUDIO_PLL_REFERENCE_FOUT	660000000
> +#define AUDIO_PLL_QDPMC_MAX		(AT91_PMC_AUDIO_PLL_QDPMC_MASK >> \
> +						AT91_PMC_AUDIO_PLL_QDPMC_OFFSET)
> +struct clk_audio_pmc {
> +	struct clk_hw hw;
> +	struct regmap *regmap;
> +	u8 qdpmc;
> +};
> +
> +#define to_clk_audio_pmc(hw) container_of(hw, struct clk_audio_pmc, hw)
> +
> +static int clk_audio_pll_pmc_enable(struct clk_hw *hw)
> +{
> +	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);
> +
> +	regmap_update_bits(apmc_ck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PMCEN |
> +			   AT91_PMC_AUDIO_PLL_QDPMC_MASK,
> +			   AT91_PMC_AUDIO_PLL_PMCEN |
> +			   AT91_PMC_AUDIO_PLL_QDPMC(apmc_ck->qdpmc));
> +	return 0;
> +}
> +
> +static void clk_audio_pll_pmc_disable(struct clk_hw *hw)
> +{
> +	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);
> +
> +	regmap_update_bits(apmc_ck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PMCEN, 0);
> +}
> +
> +static unsigned long clk_audio_pll_pmc_recalc_rate(struct clk_hw *hw,
> +						   unsigned long parent_rate)
> +{
> +	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);
> +	unsigned long apmc_rate = 0;
> +
> +	apmc_rate = parent_rate / (apmc_ck->qdpmc + 1);
> +
> +	pr_debug("A PLL/PMC: %s, apmc_rate = %lu (qdpmc = %u)\n", __func__,
> +		 apmc_rate, apmc_ck->qdpmc);
> +
> +	return apmc_rate;
> +}
> +
> +static long clk_audio_pll_pmc_round_rate(struct clk_hw *hw, unsigned long rate,
> +					 unsigned long *parent_rate)
> +{
> +	struct clk_hw *pclk = clk_hw_get_parent(hw);
> +	long best_rate = -EINVAL;
> +	unsigned long best_parent_rate = 0;
> +	u32 tmp_qd = 0, div;
> +	long tmp_rate;
> +	int tmp_diff;
> +	int best_diff = -1;
> +
> +	pr_debug("A PLL/PMC: %s, rate = %lu (parent_rate = %lu)\n", __func__,
> +		 rate, *parent_rate);
> +
> +	for (div = 1; div <= AUDIO_PLL_QDPMC_MAX; div++) {
> +		best_parent_rate = clk_round_rate(pclk->clk, rate * div);
> +		tmp_rate = best_parent_rate / div;
> +		tmp_diff = abs(rate - tmp_rate);
> +
> +		if (best_diff < 0 || best_diff > tmp_diff) {
> +			*parent_rate = best_parent_rate;
> +			best_rate = tmp_rate;
> +			best_diff = tmp_diff;
> +			tmp_qd = div;
> +		}
> +	}
> +
> +	pr_debug("A PLL/PMC: %s, best_rate = %ld, best_parent_rate = %lu (qd = %d)\n",
> +		 __func__, best_rate, *parent_rate, tmp_qd - 1);
> +
> +	return best_rate;
> +}
> +
> +static int clk_audio_pll_pmc_set_rate(struct clk_hw *hw, unsigned long rate,
> +				      unsigned long parent_rate)
> +{
> +	struct clk_audio_pmc *apmc_ck = to_clk_audio_pmc(hw);
> +
> +	if (!rate)
> +		return -EINVAL;
> +
> +	pr_debug("A PLL/PMC: %s, rate = %lu (parent_rate = %lu)\n", __func__,
> +		 rate, parent_rate);
> +
> +	apmc_ck->qdpmc = parent_rate / rate - 1;
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops audio_pll_pmc_ops = {
> +	.enable = clk_audio_pll_pmc_enable,
> +	.disable = clk_audio_pll_pmc_disable,
> +	.recalc_rate = clk_audio_pll_pmc_recalc_rate,
> +	.round_rate = clk_audio_pll_pmc_round_rate,
> +	.set_rate = clk_audio_pll_pmc_set_rate,
> +};
> +
> +static void __init of_sama5d2_clk_audio_pll_pmc_setup(struct device_node *np)
> +{
> +	struct clk_audio_pmc *apmc_ck;
> +	struct clk_init_data init;
> +	struct regmap *regmap;
> +	const char *parent_name;
> +	const char *name = np->name;
> +	int ret;
> +
> +	parent_name = of_clk_get_parent_name(np, 0);
> +
> +	of_property_read_string(np, "clock-output-names", &name);
> +
> +	regmap = syscon_node_to_regmap(of_get_parent(np));
> +	if (IS_ERR(regmap))
> +		return;
> +
> +	apmc_ck = kzalloc(sizeof(*apmc_ck), GFP_KERNEL);
> +	if (!apmc_ck)
> +		return;
> +
> +	init.name = name;
> +	init.ops = &audio_pll_pmc_ops;
> +	init.parent_names = (parent_name ? &parent_name : NULL);
> +	init.num_parents = 1;
> +	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
> +		CLK_SET_RATE_PARENT;
> +
> +	apmc_ck->hw.init = &init;
> +	apmc_ck->regmap = regmap;
> +
> +	ret = clk_hw_register(NULL, &apmc_ck->hw);
> +	if (ret)
> +		kfree(apmc_ck);
> +	else
> +		of_clk_add_hw_provider(np, of_clk_hw_simple_get, &apmc_ck->hw);
> +}
> +
> +CLK_OF_DECLARE(of_sama5d2_clk_audio_pll_pmc_setup,
> +	       "atmel,sama5d2-clk-audio-pll-pmc",
> +	       of_sama5d2_clk_audio_pll_pmc_setup);
> diff --git a/drivers/clk/at91/clk-audio-pll.c b/drivers/clk/at91/clk-audio-pll.c
> new file mode 100644
> index 000000000000..ad8c8827681e
> --- /dev/null
> +++ b/drivers/clk/at91/clk-audio-pll.c
> @@ -0,0 +1,237 @@
> +/*
> + *  Copyright (C) 2016 Atmel Corporation,
> + *		       Songjun Wu <songjun.wu@...el.com>,
> + *                     Nicolas Ferre <nicolas.ferre@...el.com>
> + *
> + * 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.
> + *
> + */
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk/at91_pmc.h>
> +#include <linux/of.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +
> +#include "pmc.h"
> +
> +/*
> + * DOC: Fractional PLL clock for audio
> + *
> + * Traits of this clock:
> + * prepare - clk_prepare puts audio PLL in reset state
> + * enable - clk_enable writes nd, fracr parameters and enables PLL
> + * rate - rate is adjustable.
> + *        clk->rate = parent->rate * ((nd + 1) + (fracr / 2^22))
> + * parent - fixed parent.  No clk_set_parent support
> + */
> +
> +#define AUDIO_PLL_DIV_FRAC	BIT(22)
> +#define AUDIO_PLL_ND_MAX	(AT91_PMC_AUDIO_PLL_ND_MASK >> \
> +					AT91_PMC_AUDIO_PLL_ND_OFFSET)
> +
> +#define AUDIO_PLL_FOUT_MIN	620000000
> +#define AUDIO_PLL_FOUT_MAX	700000000
> +
> +struct clk_audio_frac {
> +	struct clk_hw hw;
> +	struct regmap *regmap;
> +	u32 fracr;
> +	u8 nd;
> +};
> +
> +#define to_clk_audio_frac(hw) container_of(hw, struct clk_audio_frac, hw)
> +
> +static int clk_audio_pll_enable(struct clk_hw *hw)
> +{
> +	struct clk_audio_frac *fck = to_clk_audio_frac(hw);
> +
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_RESETN, 0);
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_RESETN,
> +			   AT91_PMC_AUDIO_PLL_RESETN);
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL1,
> +			   AT91_PMC_AUDIO_PLL_FRACR_MASK, fck->fracr);
> +
> +	/*
> +	 * reset and enable have to be done in 2 separated writes
> +	 * for AT91_PMC_AUDIO_PLL0
> +	 */
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PLLEN |
> +			   AT91_PMC_AUDIO_PLL_ND_MASK,
> +			   AT91_PMC_AUDIO_PLL_PLLEN |
> +			   AT91_PMC_AUDIO_PLL_ND(fck->nd));
> +
> +	return 0;
> +}
> +
> +static void clk_audio_pll_disable(struct clk_hw *hw)
> +{
> +	struct clk_audio_frac *fck = to_clk_audio_frac(hw);
> +
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_PLLEN, 0);
> +	/* do it in 2 separated writes */
> +	regmap_update_bits(fck->regmap, AT91_PMC_AUDIO_PLL0,
> +			   AT91_PMC_AUDIO_PLL_RESETN, 0);
> +}
> +
> +static unsigned long clk_audio_pll_fout(unsigned long parent_rate,
> +					unsigned long nd, unsigned long fracr)
> +{
> +	unsigned long long fr = (unsigned long long)parent_rate *
> +						(unsigned long long)fracr;
> +
> +	pr_debug("A PLL: %s, fr = %llu\n", __func__, fr);
> +
> +	fr = DIV_ROUND_CLOSEST_ULL(fr, AUDIO_PLL_DIV_FRAC);
> +
> +	pr_debug("A PLL: %s, fr = %llu\n", __func__, fr);
> +
> +	return parent_rate * (nd + 1) + fr;
> +}
> +
> +static unsigned long clk_audio_pll_recalc_rate(struct clk_hw *hw,
> +					       unsigned long parent_rate)
> +{
> +	struct clk_audio_frac *fck = to_clk_audio_frac(hw);
> +	unsigned long fout;
> +
> +	fout = clk_audio_pll_fout(parent_rate, fck->nd, fck->fracr);
> +
> +	pr_debug("A PLL: %s, fout = %lu (nd = %u, fracr = %lu)\n", __func__,
> +		 fout, fck->nd, (unsigned long)fck->fracr);
> +
> +	return fout;
> +}
> +
> +static int clk_audio_pll_compute_frac(unsigned long rate,
> +				      unsigned long parent_rate,
> +				      unsigned long *nd, unsigned long *fracr)
> +{
> +	unsigned long long tmp, rem;
> +
> +	if (!rate)
> +		return -EINVAL;
> +
> +	tmp = rate;
> +	rem = do_div(tmp, parent_rate);
> +	if (!tmp || tmp >= AUDIO_PLL_ND_MAX)
> +		return -EINVAL;
> +
> +	*nd = tmp - 1;
> +
> +	tmp = rem * AUDIO_PLL_DIV_FRAC;
> +	tmp = DIV_ROUND_CLOSEST_ULL(tmp, parent_rate);
> +	if (tmp > AT91_PMC_AUDIO_PLL_FRACR_MASK)
> +		return -EINVAL;
> +
> +	/* we can cast here as we verified the bounds just above */
> +	*fracr = (unsigned long)tmp;
> +
> +	return 0;
> +}
> +
> +static long clk_audio_pll_round_rate(struct clk_hw *hw, unsigned long rate,
> +				     unsigned long *parent_rate)
> +{
> +	long best_rate = -EINVAL;
> +	unsigned long fracr, nd;
> +	int ret;
> +
> +	pr_debug("A PLL: %s, rate = %lu (parent_rate = %lu)\n", __func__, rate,
> +		 *parent_rate);
> +
> +	if (rate < AUDIO_PLL_FOUT_MIN)
> +		rate = AUDIO_PLL_FOUT_MIN;
> +	else if (rate > AUDIO_PLL_FOUT_MAX)
> +		rate = AUDIO_PLL_FOUT_MAX;
> +
> +	ret = clk_audio_pll_compute_frac(rate, *parent_rate, &nd, &fracr);
> +	if (ret)
> +		return ret;
> +
> +	best_rate = clk_audio_pll_fout(*parent_rate, nd, fracr);
> +
> +	pr_debug("A PLL: %s, best_rate = %lu (nd = %lu, fracr = %lu)\n",
> +		 __func__, best_rate, nd, fracr);
> +
> +	return best_rate;
> +}
> +
> +static int clk_audio_pll_set_rate(struct clk_hw *hw, unsigned long rate,
> +				  unsigned long parent_rate)
> +{
> +	struct clk_audio_frac *fck = to_clk_audio_frac(hw);
> +	unsigned long fracr, nd;
> +	int ret;
> +
> +	pr_debug("A PLL: %s, rate = %lu (parent_rate = %lu)\n", __func__, rate,
> +		 parent_rate);
> +
> +	if (rate < AUDIO_PLL_FOUT_MIN || rate > AUDIO_PLL_FOUT_MAX)
> +		return -EINVAL;
> +
> +	ret = clk_audio_pll_compute_frac(rate, parent_rate, &nd, &fracr);
> +	if (ret)
> +		return ret;
> +
> +	fck->nd = nd;
> +	fck->fracr = fracr;
> +
> +	return 0;
> +}
> +
> +static const struct clk_ops audio_pll_ops = {
> +	.enable = clk_audio_pll_enable,
> +	.disable = clk_audio_pll_disable,
> +	.recalc_rate = clk_audio_pll_recalc_rate,
> +	.round_rate = clk_audio_pll_round_rate,
> +	.set_rate = clk_audio_pll_set_rate,
> +};
> +
> +static void __init of_sama5d2_clk_audio_pll_setup(struct device_node *np)
> +{
> +	struct clk_audio_frac *fck;
> +	struct clk_init_data init;
> +	struct regmap *regmap;
> +	const char *parent_name;
> +	const char *name = np->name;
> +	int ret;
> +
> +	parent_name = of_clk_get_parent_name(np, 0);
> +
> +	of_property_read_string(np, "clock-output-names", &name);
> +
> +	regmap = syscon_node_to_regmap(of_get_parent(np));
> +	if (IS_ERR(regmap))
> +		return;
> +
> +	fck = kzalloc(sizeof(*fck), GFP_KERNEL);
> +	if (!fck)
> +		return;
> +
> +	init.name = name;
> +	init.ops = &audio_pll_ops;
> +	init.parent_names = (parent_name ? &parent_name : NULL);
> +	init.num_parents = 1;
> +	init.flags = CLK_SET_RATE_GATE;
> +
> +	fck->hw.init = &init;
> +	fck->regmap = regmap;
> +
> +	ret = clk_hw_register(NULL, &fck->hw);
> +	if (ret)
> +		kfree(fck);
> +	else
> +		of_clk_add_hw_provider(np, of_clk_hw_simple_get, &fck->hw);
> +}
> +
> +CLK_OF_DECLARE(of_sama5d2_clk_audio_pll_setup,
> +	       "atmel,sama5d2-clk-audio-pll-frac",
> +	       of_sama5d2_clk_audio_pll_setup);
> diff --git a/include/linux/clk/at91_pmc.h b/include/linux/clk/at91_pmc.h
> index 17f413bbbedf..6aca5ce8a99a 100644
> --- a/include/linux/clk/at91_pmc.h
> +++ b/include/linux/clk/at91_pmc.h
> @@ -185,4 +185,29 @@
>  #define		AT91_PMC_PCR_EN			(0x1  <<  28)				/* Enable */
>  #define		AT91_PMC_PCR_GCKEN		(0x1  <<  29)				/* GCK Enable */
>  
> +#define AT91_PMC_AUDIO_PLL0	0x14c
> +#define		AT91_PMC_AUDIO_PLL_PLLEN	(1  <<  0)
> +#define		AT91_PMC_AUDIO_PLL_PADEN	(1  <<  1)
> +#define		AT91_PMC_AUDIO_PLL_PMCEN	(1  <<  2)
> +#define		AT91_PMC_AUDIO_PLL_RESETN	(1  <<  3)
> +#define		AT91_PMC_AUDIO_PLL_ND_OFFSET	8
> +#define		AT91_PMC_AUDIO_PLL_ND_MASK	(0x7f << AT91_PMC_AUDIO_PLL_ND_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_ND(n)	((n)  << AT91_PMC_AUDIO_PLL_ND_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPMC_OFFSET	16
> +#define		AT91_PMC_AUDIO_PLL_QDPMC_MASK	(0x7f << AT91_PMC_AUDIO_PLL_QDPMC_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPMC(n)	((n)  << AT91_PMC_AUDIO_PLL_QDPMC_OFFSET)
> +
> +#define AT91_PMC_AUDIO_PLL1	0x150
> +#define		AT91_PMC_AUDIO_PLL_FRACR_MASK		0x3fffff
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_OFFSET		24
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_MASK		(0x7f << AT91_PMC_AUDIO_PLL_QDPAD_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPAD(n)		((n)  << AT91_PMC_AUDIO_PLL_QDPAD_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_DIV_OFFSET	AT91_PMC_AUDIO_PLL_QDPAD_OFFSET
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_DIV_MASK	(0x3  << AT91_PMC_AUDIO_PLL_QDPAD_DIV_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_DIV(n)		((n)  << AT91_PMC_AUDIO_PLL_QDPAD_DIV_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_OFFSET	26
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MAX	0x1f
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MASK	(AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_MAX << AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_OFFSET)
> +#define		AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV(n)	((n)  << AT91_PMC_AUDIO_PLL_QDPAD_EXTDIV_OFFSET)
> +
>  #endif
> diff --git a/sound/soc/atmel/atmel-classd.c b/sound/soc/atmel/atmel-classd.c
> index b7ef8c59b49a..05bf5004fecc 100644
> --- a/sound/soc/atmel/atmel-classd.c
> +++ b/sound/soc/atmel/atmel-classd.c
> @@ -32,7 +32,6 @@ struct atmel_classd {
>  	struct regmap *regmap;
>  	struct clk *pclk;
>  	struct clk *gclk;
> -	struct clk *aclk;
>  	int irq;
>  	const struct atmel_classd_pdata *pdata;
>  };
> @@ -332,10 +331,6 @@ static int atmel_classd_codec_dai_startup(struct snd_pcm_substream *substream,
>  	struct atmel_classd *dd = snd_soc_card_get_drvdata(rtd->card);
>  	int ret;
>  
> -	ret = clk_prepare_enable(dd->aclk);
> -	if (ret)
> -		return ret;
> -
>  	return clk_prepare_enable(dd->gclk);
>  }
>  
> @@ -414,9 +409,8 @@ atmel_classd_codec_dai_hw_params(struct snd_pcm_substream *substream,
>  		sample_rates[best].rate, sample_rates[best].aclk_rate);
>  
>  	clk_disable_unprepare(dd->gclk);
> -	clk_disable_unprepare(dd->aclk);
>  
> -	ret = clk_set_rate(dd->aclk, sample_rates[best].aclk_rate);
> +	ret = clk_set_rate(dd->gclk, sample_rates[best].aclk_rate);
>  	if (ret)
>  		return ret;
>  
> @@ -426,10 +420,6 @@ atmel_classd_codec_dai_hw_params(struct snd_pcm_substream *substream,
>  
>  	snd_soc_update_bits(codec, CLASSD_INTPMR, mask, val);
>  
> -	ret = clk_prepare_enable(dd->aclk);
> -	if (ret)
> -		return ret;
> -
>  	return clk_prepare_enable(dd->gclk);
>  }
>  
> @@ -441,7 +431,6 @@ atmel_classd_codec_dai_shutdown(struct snd_pcm_substream *substream,
>  	struct atmel_classd *dd = snd_soc_card_get_drvdata(rtd->card);
>  
>  	clk_disable_unprepare(dd->gclk);
> -	clk_disable_unprepare(dd->aclk);
>  }
>  
>  static int atmel_classd_codec_dai_prepare(struct snd_pcm_substream *substream,
> @@ -596,13 +585,6 @@ static int atmel_classd_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	dd->aclk = devm_clk_get(dev, "aclk");
> -	if (IS_ERR(dd->aclk)) {
> -		ret = PTR_ERR(dd->aclk);
> -		dev_err(dev, "failed to get audio clock: %d\n", ret);
> -		return ret;
> -	}
> -
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	io_base = devm_ioremap_resource(dev, res);
>  	if (IS_ERR(io_base)) {
> -- 
> 2.11.0
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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