1 files changed, 331 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
new file mode 100644
index 000000000..e157273fd
--- /dev/null
+++ b/drivers/pwm/pwm-berlin.c
@@ -0,0 +1,331 @@
+/*
+ * Marvell Berlin PWM driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Author: Antoine Tenart <antoine.tenart@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define BERLIN_PWM_EN			0x0
+#define  BERLIN_PWM_ENABLE		BIT(0)
+#define BERLIN_PWM_CONTROL		0x4
+/*
+ * The prescaler claims to support 8 different moduli, configured using the
+ * low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64,
+ * 256, 1024, and 4096.)  However, the moduli from 4 to 1024 appear to be
+ * implemented by internally shifting TCNT left without adding additional
+ * bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff;
+ * for 8, 0x1fff; and so on. This means that those moduli are entirely
+ * useless, as we could just do the shift ourselves. The 4096 modulus is
+ * implemented with a real prescaler, so we do use that, but we treat it
+ * as a flag instead of pretending the modulus is actually configurable.
+ */
+#define  BERLIN_PWM_PRESCALE_4096	0x7
+#define  BERLIN_PWM_INVERT_POLARITY	BIT(3)
+#define BERLIN_PWM_DUTY			0x8
+#define BERLIN_PWM_TCNT			0xc
+#define  BERLIN_PWM_MAX_TCNT		65535
+
+struct berlin_pwm_channel {
+	u32 enable;
+	u32 ctrl;
+	u32 duty;
+	u32 tcnt;
+};
+
+struct berlin_pwm_chip {
+	struct pwm_chip chip;
+	struct clk *clk;
+	void __iomem *base;
+};
+
+static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct berlin_pwm_chip, chip);
+}
+
+static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *bpc,
+				   unsigned int channel, unsigned long offset)
+{
+	return readl_relaxed(bpc->base + channel * 0x10 + offset);
+}
+
+static inline void berlin_pwm_writel(struct berlin_pwm_chip *bpc,
+				     unsigned int channel, u32 value,
+				     unsigned long offset)
+{
+	writel_relaxed(value, bpc->base + channel * 0x10 + offset);
+}
+
+static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct berlin_pwm_channel *channel;
+
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return -ENOMEM;
+
+	return pwm_set_chip_data(pwm, channel);
+}
+
+static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);
+
+	kfree(channel);
+}
+
+static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			     u64 duty_ns, u64 period_ns)
+{
+	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
+	bool prescale_4096 = false;
+	u32 value, duty, period;
+	u64 cycles;
+
+	cycles = clk_get_rate(bpc->clk);
+	cycles *= period_ns;
+	do_div(cycles, NSEC_PER_SEC);
+
+	if (cycles > BERLIN_PWM_MAX_TCNT) {
+		prescale_4096 = true;
+		cycles >>= 12; // Prescaled by 4096
+
+		if (cycles > BERLIN_PWM_MAX_TCNT)
+			return -ERANGE;
+	}
+
+	period = cycles;
+	cycles *= duty_ns;
+	do_div(cycles, period_ns);
+	duty = cycles;
+
+	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);
+	if (prescale_4096)
+		value |= BERLIN_PWM_PRESCALE_4096;
+	else
+		value &= ~BERLIN_PWM_PRESCALE_4096;
+	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);
+
+	berlin_pwm_writel(bpc, pwm->hwpwm, duty, BERLIN_PWM_DUTY);
+	berlin_pwm_writel(bpc, pwm->hwpwm, period, BERLIN_PWM_TCNT);
+
+	return 0;
+}
+
+static int berlin_pwm_set_polarity(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   enum pwm_polarity polarity)
+{
+	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_CONTROL);
+
+	if (polarity == PWM_POLARITY_NORMAL)
+		value &= ~BERLIN_PWM_INVERT_POLARITY;
+	else
+		value |= BERLIN_PWM_INVERT_POLARITY;
+
+	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_CONTROL);
+
+	return 0;
+}
+
+static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
+	value |= BERLIN_PWM_ENABLE;
+	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);
+
+	return 0;
+}
+
+static void berlin_pwm_disable(struct pwm_chip *chip,
+			       struct pwm_device *pwm)
+{
+	struct berlin_pwm_chip *bpc = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(bpc, pwm->hwpwm, BERLIN_PWM_EN);
+	value &= ~BERLIN_PWM_ENABLE;
+	berlin_pwm_writel(bpc, pwm->hwpwm, value, BERLIN_PWM_EN);
+}
+
+static int berlin_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	int err;
+	bool enabled = pwm->state.enabled;
+
+	if (state->polarity != pwm->state.polarity) {
+		if (enabled) {
+			berlin_pwm_disable(chip, pwm);
+			enabled = false;
+		}
+
+		err = berlin_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			berlin_pwm_disable(chip, pwm);
+		return 0;
+	}
+
+	err = berlin_pwm_config(chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!enabled)
+		return berlin_pwm_enable(chip, pwm);
+
+	return 0;
+}
+
+static const struct pwm_ops berlin_pwm_ops = {
+	.request = berlin_pwm_request,
+	.free = berlin_pwm_free,
+	.apply = berlin_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id berlin_pwm_match[] = {
+	{ .compatible = "marvell,berlin-pwm" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, berlin_pwm_match);
+
+static int berlin_pwm_probe(struct platform_device *pdev)
+{
+	struct berlin_pwm_chip *bpc;
+	int ret;
+
+	bpc = devm_kzalloc(&pdev->dev, sizeof(*bpc), GFP_KERNEL);
+	if (!bpc)
+		return -ENOMEM;
+
+	bpc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(bpc->base))
+		return PTR_ERR(bpc->base);
+
+	bpc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(bpc->clk))
+		return PTR_ERR(bpc->clk);
+
+	ret = clk_prepare_enable(bpc->clk);
+	if (ret)
+		return ret;
+
+	bpc->chip.dev = &pdev->dev;
+	bpc->chip.ops = &berlin_pwm_ops;
+	bpc->chip.npwm = 4;
+
+	ret = pwmchip_add(&bpc->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+		clk_disable_unprepare(bpc->clk);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, bpc);
+
+	return 0;
+}
+
+static int berlin_pwm_remove(struct platform_device *pdev)
+{
+	struct berlin_pwm_chip *bpc = platform_get_drvdata(pdev);
+
+	pwmchip_remove(&bpc->chip);
+
+	clk_disable_unprepare(bpc->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int berlin_pwm_suspend(struct device *dev)
+{
+	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
+	unsigned int i;
+
+	for (i = 0; i < bpc->chip.npwm; i++) {
+		struct berlin_pwm_channel *channel;
+
+		channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
+		if (!channel)
+			continue;
+
+		channel->enable = berlin_pwm_readl(bpc, i, BERLIN_PWM_ENABLE);
+		channel->ctrl = berlin_pwm_readl(bpc, i, BERLIN_PWM_CONTROL);
+		channel->duty = berlin_pwm_readl(bpc, i, BERLIN_PWM_DUTY);
+		channel->tcnt = berlin_pwm_readl(bpc, i, BERLIN_PWM_TCNT);
+	}
+
+	clk_disable_unprepare(bpc->clk);
+
+	return 0;
+}
+
+static int berlin_pwm_resume(struct device *dev)
+{
+	struct berlin_pwm_chip *bpc = dev_get_drvdata(dev);
+	unsigned int i;
+	int ret;
+
+	ret = clk_prepare_enable(bpc->clk);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < bpc->chip.npwm; i++) {
+		struct berlin_pwm_channel *channel;
+
+		channel = pwm_get_chip_data(&bpc->chip.pwms[i]);
+		if (!channel)
+			continue;
+
+		berlin_pwm_writel(bpc, i, channel->ctrl, BERLIN_PWM_CONTROL);
+		berlin_pwm_writel(bpc, i, channel->duty, BERLIN_PWM_DUTY);
+		berlin_pwm_writel(bpc, i, channel->tcnt, BERLIN_PWM_TCNT);
+		berlin_pwm_writel(bpc, i, channel->enable, BERLIN_PWM_ENABLE);
+	}
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
+			 berlin_pwm_resume);
+
+static struct platform_driver berlin_pwm_driver = {
+	.probe = berlin_pwm_probe,
+	.remove = berlin_pwm_remove,
+	.driver = {
+		.name = "berlin-pwm",
+		.of_match_table = berlin_pwm_match,
+		.pm = &berlin_pwm_pm_ops,
+	},
+};
+module_platform_driver(berlin_pwm_driver);
+
+MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell Berlin PWM driver");
+MODULE_LICENSE("GPL v2");