1 files changed, 87 insertions, 113 deletions

diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index c5dbf16d810b..532903da521f 100644
--- a/drivers/pwm/pwm-bcm2835.c
+++ b/drivers/pwm/pwm-bcm2835.c
@@ -1,9 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright 2014 Bart Tanghe <bart.tanghe@thomasmore.be>
- *
- * 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; version 2.
  */
 
 #include <linux/clk.h>
@@ -24,172 +21,149 @@
 #define PERIOD(x)		(((x) * 0x10) + 0x10)
 #define DUTY(x)			(((x) * 0x10) + 0x14)
 
-#define MIN_PERIOD		108		/* 9.2 MHz max. PWM clock */
+#define PERIOD_MIN		0x2
 
 struct bcm2835_pwm {
-	struct pwm_chip chip;
-	struct device *dev;
 	void __iomem *base;
 	struct clk *clk;
+	unsigned long rate;
 };
 
 static inline struct bcm2835_pwm *to_bcm2835_pwm(struct pwm_chip *chip)
 {
-	return container_of(chip, struct bcm2835_pwm, chip);
+	return pwmchip_get_drvdata(chip);
 }
 
-static int bcm2835_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			     const struct pwm_state *state)
 {
-	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	u32 value;
-
-	value = readl(pc->base + PWM_CONTROL);
-	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
-	value |= (PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm));
-	writel(value, pc->base + PWM_CONTROL);
-
-	return 0;
-}
 
-static void bcm2835_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
-{
 	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	u32 value;
-
-	value = readl(pc->base + PWM_CONTROL);
-	value &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
-	writel(value, pc->base + PWM_CONTROL);
-}
-
-static int bcm2835_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
-			      int duty_ns, int period_ns)
-{
-	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	unsigned long rate = clk_get_rate(pc->clk);
-	unsigned long scaler;
-
-	if (!rate) {
-		dev_err(pc->dev, "failed to get clock rate\n");
+	unsigned long long period_cycles;
+	u64 max_period;
+
+	u32 val;
+
+	/*
+	 * period_cycles must be a 32 bit value, so period * rate / NSEC_PER_SEC
+	 * must be <= U32_MAX. As U32_MAX * NSEC_PER_SEC < U64_MAX the
+	 * multiplication period * rate doesn't overflow.
+	 * To calculate the maximal possible period that guarantees the
+	 * above inequality:
+	 *
+	 *     round(period * rate / NSEC_PER_SEC) <= U32_MAX
+	 * <=> period * rate / NSEC_PER_SEC < U32_MAX + 0.5
+	 * <=> period * rate < (U32_MAX + 0.5) * NSEC_PER_SEC
+	 * <=> period < ((U32_MAX + 0.5) * NSEC_PER_SEC) / rate
+	 * <=> period < ((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate
+	 * <=> period <= ceil((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate) - 1
+	 */
+	max_period = DIV_ROUND_UP_ULL((u64)U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC / 2, pc->rate) - 1;
+
+	if (state->period > max_period)
 		return -EINVAL;
-	}
 
-	scaler = NSEC_PER_SEC / rate;
+	/* set period */
+	period_cycles = DIV_ROUND_CLOSEST_ULL(state->period * pc->rate, NSEC_PER_SEC);
 
-	if (period_ns <= MIN_PERIOD) {
-		dev_err(pc->dev, "period %d not supported, minimum %d\n",
-			period_ns, MIN_PERIOD);
+	/* don't accept a period that is too small */
+	if (period_cycles < PERIOD_MIN)
 		return -EINVAL;
-	}
-
-	writel(duty_ns / scaler, pc->base + DUTY(pwm->hwpwm));
-	writel(period_ns / scaler, pc->base + PERIOD(pwm->hwpwm));
-
-	return 0;
-}
-
-static int bcm2835_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	u32 value;
 
-	value = readl(pc->base + PWM_CONTROL);
-	value |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm);
-	writel(value, pc->base + PWM_CONTROL);
+	writel(period_cycles, pc->base + PERIOD(pwm->hwpwm));
 
-	return 0;
-}
-
-static void bcm2835_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
-{
-	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	u32 value;
+	/* set duty cycle */
+	val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * pc->rate, NSEC_PER_SEC);
+	writel(val, pc->base + DUTY(pwm->hwpwm));
 
-	value = readl(pc->base + PWM_CONTROL);
-	value &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm));
-	writel(value, pc->base + PWM_CONTROL);
-}
+	/* set polarity */
+	val = readl(pc->base + PWM_CONTROL);
 
-static int bcm2835_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
-				enum pwm_polarity polarity)
-{
-	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	u32 value;
+	val &= ~(PWM_CONTROL_MASK << PWM_CONTROL_SHIFT(pwm->hwpwm));
+	val |= PWM_MODE << PWM_CONTROL_SHIFT(pwm->hwpwm);
 
-	value = readl(pc->base + PWM_CONTROL);
+	if (state->polarity == PWM_POLARITY_NORMAL)
+		val &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm));
+	else
+		val |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm);
 
-	if (polarity == PWM_POLARITY_NORMAL)
-		value &= ~(PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm));
+	/* enable/disable */
+	if (state->enabled)
+		val |= PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm);
 	else
-		value |= PWM_POLARITY << PWM_CONTROL_SHIFT(pwm->hwpwm);
+		val &= ~(PWM_ENABLE << PWM_CONTROL_SHIFT(pwm->hwpwm));
 
-	writel(value, pc->base + PWM_CONTROL);
+	writel(val, pc->base + PWM_CONTROL);
 
 	return 0;
 }
 
 static const struct pwm_ops bcm2835_pwm_ops = {
-	.request = bcm2835_pwm_request,
-	.free = bcm2835_pwm_free,
-	.config = bcm2835_pwm_config,
-	.enable = bcm2835_pwm_enable,
-	.disable = bcm2835_pwm_disable,
-	.set_polarity = bcm2835_set_polarity,
-	.owner = THIS_MODULE,
+	.apply = bcm2835_pwm_apply,
 };
 
 static int bcm2835_pwm_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
+	struct pwm_chip *chip;
 	struct bcm2835_pwm *pc;
-	struct resource *res;
 	int ret;
 
-	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
-	if (!pc)
-		return -ENOMEM;
-
-	pc->dev = &pdev->dev;
+	chip = devm_pwmchip_alloc(dev, 2, sizeof(*pc));
+	if (IS_ERR(chip))
+		return PTR_ERR(chip);
+	pc = to_bcm2835_pwm(chip);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	pc->base = devm_ioremap_resource(&pdev->dev, res);
+	pc->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pc->base))
 		return PTR_ERR(pc->base);
 
-	pc->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(pc->clk)) {
-		dev_err(&pdev->dev, "clock not found: %ld\n", PTR_ERR(pc->clk));
-		return PTR_ERR(pc->clk);
-	}
+	pc->clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(pc->clk))
+		return dev_err_probe(dev, PTR_ERR(pc->clk),
+				     "clock not found\n");
 
-	ret = clk_prepare_enable(pc->clk);
+	ret = devm_clk_rate_exclusive_get(dev, pc->clk);
 	if (ret)
-		return ret;
+		return dev_err_probe(dev, ret,
+				     "fail to get exclusive rate\n");
 
-	pc->chip.dev = &pdev->dev;
-	pc->chip.ops = &bcm2835_pwm_ops;
-	pc->chip.npwm = 2;
+	pc->rate = clk_get_rate(pc->clk);
+	if (!pc->rate)
+		return dev_err_probe(dev, -EINVAL,
+				     "failed to get clock rate\n");
+
+	chip->ops = &bcm2835_pwm_ops;
+	chip->atomic = true;
 
 	platform_set_drvdata(pdev, pc);
 
-	ret = pwmchip_add(&pc->chip);
+	ret = devm_pwmchip_add(dev, chip);
 	if (ret < 0)
-		goto add_fail;
+		return dev_err_probe(dev, ret, "failed to add pwmchip\n");
 
 	return 0;
-
-add_fail:
-	clk_disable_unprepare(pc->clk);
-	return ret;
 }
 
-static int bcm2835_pwm_remove(struct platform_device *pdev)
+static int bcm2835_pwm_suspend(struct device *dev)
 {
-	struct bcm2835_pwm *pc = platform_get_drvdata(pdev);
+	struct bcm2835_pwm *pc = dev_get_drvdata(dev);
 
 	clk_disable_unprepare(pc->clk);
 
-	return pwmchip_remove(&pc->chip);
+	return 0;
 }
 
+static int bcm2835_pwm_resume(struct device *dev)
+{
+	struct bcm2835_pwm *pc = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(pc->clk);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(bcm2835_pwm_pm_ops, bcm2835_pwm_suspend,
+				bcm2835_pwm_resume);
+
 static const struct of_device_id bcm2835_pwm_of_match[] = {
 	{ .compatible = "brcm,bcm2835-pwm", },
 	{ /* sentinel */ }
@@ -200,9 +174,9 @@ static struct platform_driver bcm2835_pwm_driver = {
 	.driver = {
 		.name = "bcm2835-pwm",
 		.of_match_table = bcm2835_pwm_of_match,
+		.pm = pm_ptr(&bcm2835_pwm_pm_ops),
 	},
 	.probe = bcm2835_pwm_probe,
-	.remove = bcm2835_pwm_remove,
 };
 module_platform_driver(bcm2835_pwm_driver);