drivers/pwm/pwm-meson.c - kernel/msm-4.9 - Gitiles

 /*
  * This file is provided under a dual BSD/GPLv2 license.  When using or
  * redistributing this file, you may do so under either license.
  *
  * GPL LICENSE SUMMARY
  *
  * Copyright (c) 2016 BayLibre, SAS.
  * Author: Neil Armstrong <narmstrong@baylibre.com>
  * Copyright (C) 2014 Amlogic, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  * The full GNU General Public License is included in this distribution
  * in the file called COPYING.
  *
  * BSD LICENSE
  *
  * Copyright (c) 2016 BayLibre, SAS.
  * Author: Neil Armstrong <narmstrong@baylibre.com>
  * Copyright (C) 2014 Amlogic, Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  *   * Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *   * Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in
  *     the documentation and/or other materials provided with the
  *     distribution.
  *   * Neither the name of Intel Corporation nor the names of its
  *     contributors may be used to endorse or promote products derived
  *     from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>

 #define REG_PWM_A		0x0
 #define REG_PWM_B		0x4
 #define PWM_HIGH_SHIFT		16

 #define REG_MISC_AB		0x8
 #define MISC_B_CLK_EN		BIT(23)
 #define MISC_A_CLK_EN		BIT(15)
 #define MISC_CLK_DIV_MASK	0x7f
 #define MISC_B_CLK_DIV_SHIFT	16
 #define MISC_A_CLK_DIV_SHIFT	8
 #define MISC_B_CLK_SEL_SHIFT	6
 #define MISC_A_CLK_SEL_SHIFT	4
 #define MISC_CLK_SEL_WIDTH	2
 #define MISC_B_EN		BIT(1)
 #define MISC_A_EN		BIT(0)

 static const unsigned int mux_reg_shifts[] = {
 	MISC_A_CLK_SEL_SHIFT,
 	MISC_B_CLK_SEL_SHIFT
 };

 struct meson_pwm_channel {
 	unsigned int hi;
 	unsigned int lo;
 	u8 pre_div;

 	struct pwm_state state;

 	struct clk *clk_parent;
 	struct clk_mux mux;
 	struct clk *clk;
 };

 struct meson_pwm_data {
 	const char * const *parent_names;
 };

 struct meson_pwm {
 	struct pwm_chip chip;
 	const struct meson_pwm_data *data;
 	void __iomem *base;
 	u8 inverter_mask;
 	/*
 	 * Protects register (write) access to the REG_MISC_AB register
 	 * that is shared between the two PWMs.
 	 */
 	spinlock_t lock;
 };

 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct meson_pwm, chip);
 }

 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 	struct device *dev = chip->dev;
 	int err;

 	if (!channel)
 		return -ENODEV;

 	if (channel->clk_parent) {
 		err = clk_set_parent(channel->clk, channel->clk_parent);
 		if (err < 0) {
 			dev_err(dev, "failed to set parent %s for %s: %d\n",
 				__clk_get_name(channel->clk_parent),
 				__clk_get_name(channel->clk), err);
 				return err;
 		}
 	}

 	err = clk_prepare_enable(channel->clk);
 	if (err < 0) {
 		dev_err(dev, "failed to enable clock %s: %d\n",
 			__clk_get_name(channel->clk), err);
 		return err;
 	}

 	chip->ops->get_state(chip, pwm, &channel->state);

 	return 0;
 }

 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);

 	if (channel)
 		clk_disable_unprepare(channel->clk);
 }

 static int meson_pwm_calc(struct meson_pwm *meson,
 			  struct meson_pwm_channel *channel, unsigned int id,
 			  unsigned int duty, unsigned int period)
 {
 	unsigned int pre_div, cnt, duty_cnt;
 	unsigned long fin_freq = -1, fin_ns;

 	if (~(meson->inverter_mask >> id) & 0x1)
 		duty = period - duty;

 	if (period == channel->state.period &&
 	    duty == channel->state.duty_cycle)
 		return 0;

 	fin_freq = clk_get_rate(channel->clk);
 	if (fin_freq == 0) {
 		dev_err(meson->chip.dev, "invalid source clock frequency\n");
 		return -EINVAL;
 	}

 	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
 	fin_ns = NSEC_PER_SEC / fin_freq;

 	/* Calc pre_div with the period */
 	for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
 		cnt = DIV_ROUND_CLOSEST(period, fin_ns * (pre_div + 1));
 		dev_dbg(meson->chip.dev, "fin_ns=%lu pre_div=%u cnt=%u\n",
 			fin_ns, pre_div, cnt);
 		if (cnt <= 0xffff)
 			break;
 	}

 	if (pre_div == MISC_CLK_DIV_MASK) {
 		dev_err(meson->chip.dev, "unable to get period pre_div\n");
 		return -EINVAL;
 	}

 	dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
 		pre_div, cnt);

 	if (duty == period) {
 		channel->pre_div = pre_div;
 		channel->hi = cnt;
 		channel->lo = 0;
 	} else if (duty == 0) {
 		channel->pre_div = pre_div;
 		channel->hi = 0;
 		channel->lo = cnt;
 	} else {
 		/* Then check is we can have the duty with the same pre_div */
 		duty_cnt = DIV_ROUND_CLOSEST(duty, fin_ns * (pre_div + 1));
 		if (duty_cnt > 0xffff) {
 			dev_err(meson->chip.dev, "unable to get duty cycle\n");
 			return -EINVAL;
 		}

 		dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
 			duty, pre_div, duty_cnt);

 		channel->pre_div = pre_div;
 		channel->hi = duty_cnt;
 		channel->lo = cnt - duty_cnt;
 	}

 	return 0;
 }

 static void meson_pwm_enable(struct meson_pwm *meson,
 			     struct meson_pwm_channel *channel,
 			     unsigned int id)
 {
 	u32 value, clk_shift, clk_enable, enable;
 	unsigned int offset;
 	unsigned long flags;

 	switch (id) {
 	case 0:
 		clk_shift = MISC_A_CLK_DIV_SHIFT;
 		clk_enable = MISC_A_CLK_EN;
 		enable = MISC_A_EN;
 		offset = REG_PWM_A;
 		break;

 	case 1:
 		clk_shift = MISC_B_CLK_DIV_SHIFT;
 		clk_enable = MISC_B_CLK_EN;
 		enable = MISC_B_EN;
 		offset = REG_PWM_B;
 		break;

 	default:
 		return;
 	}

 	spin_lock_irqsave(&meson->lock, flags);

 	value = readl(meson->base + REG_MISC_AB);
 	value &= ~(MISC_CLK_DIV_MASK << clk_shift);
 	value |= channel->pre_div << clk_shift;
 	value |= clk_enable;
 	writel(value, meson->base + REG_MISC_AB);

 	value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
 	writel(value, meson->base + offset);

 	value = readl(meson->base + REG_MISC_AB);
 	value |= enable;
 	writel(value, meson->base + REG_MISC_AB);

 	spin_unlock_irqrestore(&meson->lock, flags);
 }

 static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
 {
 	u32 value, enable;
 	unsigned long flags;

 	switch (id) {
 	case 0:
 		enable = MISC_A_EN;
 		break;

 	case 1:
 		enable = MISC_B_EN;
 		break;

 	default:
 		return;
 	}

 	spin_lock_irqsave(&meson->lock, flags);

 	value = readl(meson->base + REG_MISC_AB);
 	value &= ~enable;
 	writel(value, meson->base + REG_MISC_AB);

 	spin_unlock_irqrestore(&meson->lock, flags);
 }

 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			   struct pwm_state *state)
 {
 	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 	struct meson_pwm *meson = to_meson_pwm(chip);
 	int err = 0;

 	if (!state)
 		return -EINVAL;

 	if (!state->enabled) {
 		meson_pwm_disable(meson, pwm->hwpwm);
 		channel->state.enabled = false;

 		return 0;
 	}

 	if (state->period != channel->state.period ||
 	    state->duty_cycle != channel->state.duty_cycle ||
 	    state->polarity != channel->state.polarity) {
 		if (state->polarity != channel->state.polarity) {
 			if (state->polarity == PWM_POLARITY_NORMAL)
 				meson->inverter_mask |= BIT(pwm->hwpwm);
 			else
 				meson->inverter_mask &= ~BIT(pwm->hwpwm);
 		}

 		err = meson_pwm_calc(meson, channel, pwm->hwpwm,
 				     state->duty_cycle, state->period);
 		if (err < 0)
 			return err;

 		channel->state.polarity = state->polarity;
 		channel->state.period = state->period;
 		channel->state.duty_cycle = state->duty_cycle;
 	}

 	if (state->enabled && !channel->state.enabled) {
 		meson_pwm_enable(meson, channel, pwm->hwpwm);
 		channel->state.enabled = true;
 	}

 	return 0;
 }

 static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 				struct pwm_state *state)
 {
 	struct meson_pwm *meson = to_meson_pwm(chip);
 	u32 value, mask;

 	if (!state)
 		return;

 	switch (pwm->hwpwm) {
 	case 0:
 		mask = MISC_A_EN;
 		break;

 	case 1:
 		mask = MISC_B_EN;
 		break;

 	default:
 		return;
 	}

 	value = readl(meson->base + REG_MISC_AB);
 	state->enabled = (value & mask) != 0;
 }

 static const struct pwm_ops meson_pwm_ops = {
 	.request = meson_pwm_request,
 	.free = meson_pwm_free,
 	.apply = meson_pwm_apply,
 	.get_state = meson_pwm_get_state,
 	.owner = THIS_MODULE,
 };

 static const char * const pwm_meson8b_parent_names[] = {
 	"xtal", "vid_pll", "fclk_div4", "fclk_div3"
 };

 static const struct meson_pwm_data pwm_meson8b_data = {
 	.parent_names = pwm_meson8b_parent_names,
 };

 static const char * const pwm_gxbb_parent_names[] = {
 	"xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
 };

 static const struct meson_pwm_data pwm_gxbb_data = {
 	.parent_names = pwm_gxbb_parent_names,
 };

 static const struct of_device_id meson_pwm_matches[] = {
 	{ .compatible = "amlogic,meson8b-pwm", .data = &pwm_meson8b_data },
 	{ .compatible = "amlogic,meson-gxbb-pwm", .data = &pwm_gxbb_data },
 	{},
 };
 MODULE_DEVICE_TABLE(of, meson_pwm_matches);

 static int meson_pwm_init_channels(struct meson_pwm *meson,
 				   struct meson_pwm_channel *channels)
 {
 	struct device *dev = meson->chip.dev;
 	struct device_node *np = dev->of_node;
 	struct clk_init_data init;
 	unsigned int i;
 	char name[255];
 	int err;

 	for (i = 0; i < meson->chip.npwm; i++) {
 		struct meson_pwm_channel *channel = &channels[i];

 		snprintf(name, sizeof(name), "%s#mux%u", np->full_name, i);

 		init.name = name;
 		init.ops = &clk_mux_ops;
 		init.flags = CLK_IS_BASIC;
 		init.parent_names = meson->data->parent_names;
 		init.num_parents = 1 << MISC_CLK_SEL_WIDTH;

 		channel->mux.reg = meson->base + REG_MISC_AB;
 		channel->mux.shift = mux_reg_shifts[i];
 		channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
 		channel->mux.flags = 0;
 		channel->mux.lock = &meson->lock;
 		channel->mux.table = NULL;
 		channel->mux.hw.init = &init;

 		channel->clk = devm_clk_register(dev, &channel->mux.hw);
 		if (IS_ERR(channel->clk)) {
 			err = PTR_ERR(channel->clk);
 			dev_err(dev, "failed to register %s: %d\n", name, err);
 			return err;
 		}

 		snprintf(name, sizeof(name), "clkin%u", i);

 		channel->clk_parent = devm_clk_get(dev, name);
 		if (IS_ERR(channel->clk_parent)) {
 			err = PTR_ERR(channel->clk_parent);
 			if (err == -EPROBE_DEFER)
 				return err;

 			channel->clk_parent = NULL;
 		}
 	}

 	return 0;
 }

 static void meson_pwm_add_channels(struct meson_pwm *meson,
 				   struct meson_pwm_channel *channels)
 {
 	unsigned int i;

 	for (i = 0; i < meson->chip.npwm; i++)
 		pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
 }

 static int meson_pwm_probe(struct platform_device *pdev)
 {
 	struct meson_pwm_channel *channels;
 	struct meson_pwm *meson;
 	struct resource *regs;
 	int err;

 	meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
 	if (!meson)
 		return -ENOMEM;

 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	meson->base = devm_ioremap_resource(&pdev->dev, regs);
 	if (IS_ERR(meson->base))
 		return PTR_ERR(meson->base);

 	spin_lock_init(&meson->lock);
 	meson->chip.dev = &pdev->dev;
 	meson->chip.ops = &meson_pwm_ops;
 	meson->chip.base = -1;
 	meson->chip.npwm = 2;
 	meson->chip.of_xlate = of_pwm_xlate_with_flags;
 	meson->chip.of_pwm_n_cells = 3;

 	meson->data = of_device_get_match_data(&pdev->dev);
 	meson->inverter_mask = BIT(meson->chip.npwm) - 1;

 	channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
 				GFP_KERNEL);
 	if (!channels)
 		return -ENOMEM;

 	err = meson_pwm_init_channels(meson, channels);
 	if (err < 0)
 		return err;

 	err = pwmchip_add(&meson->chip);
 	if (err < 0) {
 		dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
 		return err;
 	}

 	meson_pwm_add_channels(meson, channels);

 	platform_set_drvdata(pdev, meson);

 	return 0;
 }

 static int meson_pwm_remove(struct platform_device *pdev)
 {
 	struct meson_pwm *meson = platform_get_drvdata(pdev);

 	return pwmchip_remove(&meson->chip);
 }

 static struct platform_driver meson_pwm_driver = {
 	.driver = {
 		.name = "meson-pwm",
 		.of_match_table = meson_pwm_matches,
 	},
 	.probe = meson_pwm_probe,
 	.remove = meson_pwm_remove,
 };
 module_platform_driver(meson_pwm_driver);

 MODULE_ALIAS("platform:meson-pwm");
 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 MODULE_LICENSE("Dual BSD/GPL");
	/*
	* This file is provided under a dual BSD/GPLv2 license. When using or
	* redistributing this file, you may do so under either license.
	*
	* GPL LICENSE SUMMARY
	*
	* Copyright (c) 2016 BayLibre, SAS.
	* Author: Neil Armstrong <narmstrong@baylibre.com>
	* Copyright (C) 2014 Amlogic, Inc.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of version 2 of the GNU General Public License 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, see <http://www.gnu.org/licenses/>.
	* The full GNU General Public License is included in this distribution
	* in the file called COPYING.
	*
	* BSD LICENSE
	*
	* Copyright (c) 2016 BayLibre, SAS.
	* Author: Neil Armstrong <narmstrong@baylibre.com>
	* Copyright (C) 2014 Amlogic, Inc.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Intel Corporation nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <linux/clk.h>
	#include <linux/clk-provider.h>
	#include <linux/err.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>

	#define REG_PWM_A 0x0
	#define REG_PWM_B 0x4
	#define PWM_HIGH_SHIFT 16

	#define REG_MISC_AB 0x8
	#define MISC_B_CLK_EN BIT(23)
	#define MISC_A_CLK_EN BIT(15)
	#define MISC_CLK_DIV_MASK 0x7f
	#define MISC_B_CLK_DIV_SHIFT 16
	#define MISC_A_CLK_DIV_SHIFT 8
	#define MISC_B_CLK_SEL_SHIFT 6
	#define MISC_A_CLK_SEL_SHIFT 4
	#define MISC_CLK_SEL_WIDTH 2
	#define MISC_B_EN BIT(1)
	#define MISC_A_EN BIT(0)

	static const unsigned int mux_reg_shifts[] = {
	MISC_A_CLK_SEL_SHIFT,
	MISC_B_CLK_SEL_SHIFT
	};

	struct meson_pwm_channel {
	unsigned int hi;
	unsigned int lo;
	u8 pre_div;

	struct pwm_state state;

	struct clk *clk_parent;
	struct clk_mux mux;
	struct clk *clk;
	};

	struct meson_pwm_data {
	const char * const *parent_names;
	};

	struct meson_pwm {
	struct pwm_chip chip;
	const struct meson_pwm_data *data;
	void __iomem *base;
	u8 inverter_mask;
	/*
	* Protects register (write) access to the REG_MISC_AB register
	* that is shared between the two PWMs.
	*/
	spinlock_t lock;
	};

	static inline struct meson_pwm to_meson_pwm(struct pwm_chip chip)
	{
	return container_of(chip, struct meson_pwm, chip);
	}

	static int meson_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
	struct device *dev = chip->dev;
	int err;

	if (!channel)
	return -ENODEV;

	if (channel->clk_parent) {
	err = clk_set_parent(channel->clk, channel->clk_parent);
	if (err < 0) {
	dev_err(dev, "failed to set parent %s for %s: %d\n",
	__clk_get_name(channel->clk_parent),
	__clk_get_name(channel->clk), err);
	return err;
	}
	}

	err = clk_prepare_enable(channel->clk);
	if (err < 0) {
	dev_err(dev, "failed to enable clock %s: %d\n",
	__clk_get_name(channel->clk), err);
	return err;
	}

	chip->ops->get_state(chip, pwm, &channel->state);

	return 0;
	}

	static void meson_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
	{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);

	if (channel)
	clk_disable_unprepare(channel->clk);
	}

	static int meson_pwm_calc(struct meson_pwm *meson,
	struct meson_pwm_channel *channel, unsigned int id,
	unsigned int duty, unsigned int period)
	{
	unsigned int pre_div, cnt, duty_cnt;
	unsigned long fin_freq = -1, fin_ns;

	if (~(meson->inverter_mask >> id) & 0x1)
	duty = period - duty;

	if (period == channel->state.period &&
	duty == channel->state.duty_cycle)
	return 0;

	fin_freq = clk_get_rate(channel->clk);
	if (fin_freq == 0) {
	dev_err(meson->chip.dev, "invalid source clock frequency\n");
	return -EINVAL;
	}

	dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
	fin_ns = NSEC_PER_SEC / fin_freq;

	/* Calc pre_div with the period */
	for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
	cnt = DIV_ROUND_CLOSEST(period, fin_ns * (pre_div + 1));
	dev_dbg(meson->chip.dev, "fin_ns=%lu pre_div=%u cnt=%u\n",
	fin_ns, pre_div, cnt);
	if (cnt <= 0xffff)
	break;
	}

	if (pre_div == MISC_CLK_DIV_MASK) {
	dev_err(meson->chip.dev, "unable to get period pre_div\n");
	return -EINVAL;
	}

	dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
	pre_div, cnt);

	if (duty == period) {
	channel->pre_div = pre_div;
	channel->hi = cnt;
	channel->lo = 0;
	} else if (duty == 0) {
	channel->pre_div = pre_div;
	channel->hi = 0;
	channel->lo = cnt;
	} else {
	/* Then check is we can have the duty with the same pre_div */
	duty_cnt = DIV_ROUND_CLOSEST(duty, fin_ns * (pre_div + 1));
	if (duty_cnt > 0xffff) {
	dev_err(meson->chip.dev, "unable to get duty cycle\n");
	return -EINVAL;
	}

	dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
	duty, pre_div, duty_cnt);

	channel->pre_div = pre_div;
	channel->hi = duty_cnt;
	channel->lo = cnt - duty_cnt;
	}

	return 0;
	}

	static void meson_pwm_enable(struct meson_pwm *meson,
	struct meson_pwm_channel *channel,
	unsigned int id)
	{
	u32 value, clk_shift, clk_enable, enable;
	unsigned int offset;
	unsigned long flags;

	switch (id) {
	case 0:
	clk_shift = MISC_A_CLK_DIV_SHIFT;
	clk_enable = MISC_A_CLK_EN;
	enable = MISC_A_EN;
	offset = REG_PWM_A;
	break;

	case 1:
	clk_shift = MISC_B_CLK_DIV_SHIFT;
	clk_enable = MISC_B_CLK_EN;
	enable = MISC_B_EN;
	offset = REG_PWM_B;
	break;

	default:
	return;
	}

	spin_lock_irqsave(&meson->lock, flags);

	value = readl(meson->base + REG_MISC_AB);
	value &= ~(MISC_CLK_DIV_MASK << clk_shift);
	value \|= channel->pre_div << clk_shift;
	value \|= clk_enable;
	writel(value, meson->base + REG_MISC_AB);

	value = (channel->hi << PWM_HIGH_SHIFT) \| channel->lo;
	writel(value, meson->base + offset);

	value = readl(meson->base + REG_MISC_AB);
	value \|= enable;
	writel(value, meson->base + REG_MISC_AB);

	spin_unlock_irqrestore(&meson->lock, flags);
	}

	static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
	{
	u32 value, enable;
	unsigned long flags;

	switch (id) {
	case 0:
	enable = MISC_A_EN;
	break;

	case 1:
	enable = MISC_B_EN;
	break;

	default:
	return;
	}

	spin_lock_irqsave(&meson->lock, flags);

	value = readl(meson->base + REG_MISC_AB);
	value &= ~enable;
	writel(value, meson->base + REG_MISC_AB);

	spin_unlock_irqrestore(&meson->lock, flags);
	}

	static int meson_pwm_apply(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
	struct meson_pwm *meson = to_meson_pwm(chip);
	int err = 0;

	if (!state)
	return -EINVAL;

	if (!state->enabled) {
	meson_pwm_disable(meson, pwm->hwpwm);
	channel->state.enabled = false;

	return 0;
	}

	if (state->period != channel->state.period \|\|
	state->duty_cycle != channel->state.duty_cycle \|\|
	state->polarity != channel->state.polarity) {
	if (state->polarity != channel->state.polarity) {
	if (state->polarity == PWM_POLARITY_NORMAL)
	meson->inverter_mask \|= BIT(pwm->hwpwm);
	else
	meson->inverter_mask &= ~BIT(pwm->hwpwm);
	}

	err = meson_pwm_calc(meson, channel, pwm->hwpwm,
	state->duty_cycle, state->period);
	if (err < 0)
	return err;

	channel->state.polarity = state->polarity;
	channel->state.period = state->period;
	channel->state.duty_cycle = state->duty_cycle;
	}

	if (state->enabled && !channel->state.enabled) {
	meson_pwm_enable(meson, channel, pwm->hwpwm);
	channel->state.enabled = true;
	}

	return 0;
	}

	static void meson_pwm_get_state(struct pwm_chip chip, struct pwm_device pwm,
	struct pwm_state *state)
	{
	struct meson_pwm *meson = to_meson_pwm(chip);
	u32 value, mask;

	if (!state)
	return;

	switch (pwm->hwpwm) {
	case 0:
	mask = MISC_A_EN;
	break;

	case 1:
	mask = MISC_B_EN;
	break;

	default:
	return;
	}

	value = readl(meson->base + REG_MISC_AB);
	state->enabled = (value & mask) != 0;
	}

	static const struct pwm_ops meson_pwm_ops = {
	.request = meson_pwm_request,
	.free = meson_pwm_free,
	.apply = meson_pwm_apply,
	.get_state = meson_pwm_get_state,
	.owner = THIS_MODULE,
	};

	static const char * const pwm_meson8b_parent_names[] = {
	"xtal", "vid_pll", "fclk_div4", "fclk_div3"
	};

	static const struct meson_pwm_data pwm_meson8b_data = {
	.parent_names = pwm_meson8b_parent_names,
	};

	static const char * const pwm_gxbb_parent_names[] = {
	"xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
	};

	static const struct meson_pwm_data pwm_gxbb_data = {
	.parent_names = pwm_gxbb_parent_names,
	};

	static const struct of_device_id meson_pwm_matches[] = {
	{ .compatible = "amlogic,meson8b-pwm", .data = &pwm_meson8b_data },
	{ .compatible = "amlogic,meson-gxbb-pwm", .data = &pwm_gxbb_data },
	{},
	};
	MODULE_DEVICE_TABLE(of, meson_pwm_matches);

	static int meson_pwm_init_channels(struct meson_pwm *meson,
	struct meson_pwm_channel *channels)
	{
	struct device *dev = meson->chip.dev;
	struct device_node *np = dev->of_node;
	struct clk_init_data init;
	unsigned int i;
	char name[255];
	int err;

	for (i = 0; i < meson->chip.npwm; i++) {
	struct meson_pwm_channel *channel = &channels[i];

	snprintf(name, sizeof(name), "%s#mux%u", np->full_name, i);

	init.name = name;
	init.ops = &clk_mux_ops;
	init.flags = CLK_IS_BASIC;
	init.parent_names = meson->data->parent_names;
	init.num_parents = 1 << MISC_CLK_SEL_WIDTH;

	channel->mux.reg = meson->base + REG_MISC_AB;
	channel->mux.shift = mux_reg_shifts[i];
	channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
	channel->mux.flags = 0;
	channel->mux.lock = &meson->lock;
	channel->mux.table = NULL;
	channel->mux.hw.init = &init;

	channel->clk = devm_clk_register(dev, &channel->mux.hw);
	if (IS_ERR(channel->clk)) {
	err = PTR_ERR(channel->clk);
	dev_err(dev, "failed to register %s: %d\n", name, err);
	return err;
	}

	snprintf(name, sizeof(name), "clkin%u", i);

	channel->clk_parent = devm_clk_get(dev, name);
	if (IS_ERR(channel->clk_parent)) {
	err = PTR_ERR(channel->clk_parent);
	if (err == -EPROBE_DEFER)
	return err;

	channel->clk_parent = NULL;
	}
	}

	return 0;
	}

	static void meson_pwm_add_channels(struct meson_pwm *meson,
	struct meson_pwm_channel *channels)
	{
	unsigned int i;

	for (i = 0; i < meson->chip.npwm; i++)
	pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
	}

	static int meson_pwm_probe(struct platform_device *pdev)
	{
	struct meson_pwm_channel *channels;
	struct meson_pwm *meson;
	struct resource *regs;
	int err;

	meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
	if (!meson)
	return -ENOMEM;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	meson->base = devm_ioremap_resource(&pdev->dev, regs);
	if (IS_ERR(meson->base))
	return PTR_ERR(meson->base);

	spin_lock_init(&meson->lock);
	meson->chip.dev = &pdev->dev;
	meson->chip.ops = &meson_pwm_ops;
	meson->chip.base = -1;
	meson->chip.npwm = 2;
	meson->chip.of_xlate = of_pwm_xlate_with_flags;
	meson->chip.of_pwm_n_cells = 3;

	meson->data = of_device_get_match_data(&pdev->dev);
	meson->inverter_mask = BIT(meson->chip.npwm) - 1;

	channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
	GFP_KERNEL);
	if (!channels)
	return -ENOMEM;

	err = meson_pwm_init_channels(meson, channels);
	if (err < 0)
	return err;

	err = pwmchip_add(&meson->chip);
	if (err < 0) {
	dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
	return err;
	}

	meson_pwm_add_channels(meson, channels);

	platform_set_drvdata(pdev, meson);

	return 0;
	}

	static int meson_pwm_remove(struct platform_device *pdev)
	{
	struct meson_pwm *meson = platform_get_drvdata(pdev);

	return pwmchip_remove(&meson->chip);
	}

	static struct platform_driver meson_pwm_driver = {
	.driver = {
	.name = "meson-pwm",
	.of_match_table = meson_pwm_matches,
	},
	.probe = meson_pwm_probe,
	.remove = meson_pwm_remove,
	};
	module_platform_driver(meson_pwm_driver);

	MODULE_ALIAS("platform:meson-pwm");
	MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
	MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
	MODULE_LICENSE("Dual BSD/GPL");