1 files changed, 505 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-renesas-tpu.c b/drivers/pwm/pwm-renesas-tpu.c
new file mode 100644
index 000000000..d7311614c
--- /dev/null
+++ b/drivers/pwm/pwm-renesas-tpu.c
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * R-Mobile TPU PWM driver
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define TPU_CHANNEL_MAX		4
+
+#define TPU_TSTR		0x00	/* Timer start register (shared) */
+
+#define TPU_TCRn		0x00	/* Timer control register */
+#define TPU_TCR_CCLR_NONE	(0 << 5)
+#define TPU_TCR_CCLR_TGRA	(1 << 5)
+#define TPU_TCR_CCLR_TGRB	(2 << 5)
+#define TPU_TCR_CCLR_TGRC	(5 << 5)
+#define TPU_TCR_CCLR_TGRD	(6 << 5)
+#define TPU_TCR_CKEG_RISING	(0 << 3)
+#define TPU_TCR_CKEG_FALLING	(1 << 3)
+#define TPU_TCR_CKEG_BOTH	(2 << 3)
+#define TPU_TMDRn		0x04	/* Timer mode register */
+#define TPU_TMDR_BFWT		(1 << 6)
+#define TPU_TMDR_BFB		(1 << 5)
+#define TPU_TMDR_BFA		(1 << 4)
+#define TPU_TMDR_MD_NORMAL	(0 << 0)
+#define TPU_TMDR_MD_PWM		(2 << 0)
+#define TPU_TIORn		0x08	/* Timer I/O control register */
+#define TPU_TIOR_IOA_0		(0 << 0)
+#define TPU_TIOR_IOA_0_CLR	(1 << 0)
+#define TPU_TIOR_IOA_0_SET	(2 << 0)
+#define TPU_TIOR_IOA_0_TOGGLE	(3 << 0)
+#define TPU_TIOR_IOA_1		(4 << 0)
+#define TPU_TIOR_IOA_1_CLR	(5 << 0)
+#define TPU_TIOR_IOA_1_SET	(6 << 0)
+#define TPU_TIOR_IOA_1_TOGGLE	(7 << 0)
+#define TPU_TIERn		0x0c	/* Timer interrupt enable register */
+#define TPU_TSRn		0x10	/* Timer status register */
+#define TPU_TCNTn		0x14	/* Timer counter */
+#define TPU_TGRAn		0x18	/* Timer general register A */
+#define TPU_TGRBn		0x1c	/* Timer general register B */
+#define TPU_TGRCn		0x20	/* Timer general register C */
+#define TPU_TGRDn		0x24	/* Timer general register D */
+
+#define TPU_CHANNEL_OFFSET	0x10
+#define TPU_CHANNEL_SIZE	0x40
+
+enum tpu_pin_state {
+	TPU_PIN_INACTIVE,		/* Pin is driven inactive */
+	TPU_PIN_PWM,			/* Pin is driven by PWM */
+	TPU_PIN_ACTIVE,			/* Pin is driven active */
+};
+
+struct tpu_device;
+
+struct tpu_pwm_device {
+	bool timer_on;			/* Whether the timer is running */
+
+	struct tpu_device *tpu;
+	unsigned int channel;		/* Channel number in the TPU */
+
+	enum pwm_polarity polarity;
+	unsigned int prescaler;
+	u16 period;
+	u16 duty;
+};
+
+struct tpu_device {
+	struct platform_device *pdev;
+	struct pwm_chip chip;
+	spinlock_t lock;
+
+	void __iomem *base;
+	struct clk *clk;
+};
+
+#define to_tpu_device(c)	container_of(c, struct tpu_device, chip)
+
+static void tpu_pwm_write(struct tpu_pwm_device *tpd, int reg_nr, u16 value)
+{
+	void __iomem *base = tpd->tpu->base + TPU_CHANNEL_OFFSET
+			   + tpd->channel * TPU_CHANNEL_SIZE;
+
+	iowrite16(value, base + reg_nr);
+}
+
+static void tpu_pwm_set_pin(struct tpu_pwm_device *tpd,
+			    enum tpu_pin_state state)
+{
+	static const char * const states[] = { "inactive", "PWM", "active" };
+
+	dev_dbg(&tpd->tpu->pdev->dev, "%u: configuring pin as %s\n",
+		tpd->channel, states[state]);
+
+	switch (state) {
+	case TPU_PIN_INACTIVE:
+		tpu_pwm_write(tpd, TPU_TIORn,
+			      tpd->polarity == PWM_POLARITY_INVERSED ?
+			      TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0);
+		break;
+	case TPU_PIN_PWM:
+		tpu_pwm_write(tpd, TPU_TIORn,
+			      tpd->polarity == PWM_POLARITY_INVERSED ?
+			      TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR);
+		break;
+	case TPU_PIN_ACTIVE:
+		tpu_pwm_write(tpd, TPU_TIORn,
+			      tpd->polarity == PWM_POLARITY_INVERSED ?
+			      TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1);
+		break;
+	}
+}
+
+static void tpu_pwm_start_stop(struct tpu_pwm_device *tpd, int start)
+{
+	unsigned long flags;
+	u16 value;
+
+	spin_lock_irqsave(&tpd->tpu->lock, flags);
+	value = ioread16(tpd->tpu->base + TPU_TSTR);
+
+	if (start)
+		value |= 1 << tpd->channel;
+	else
+		value &= ~(1 << tpd->channel);
+
+	iowrite16(value, tpd->tpu->base + TPU_TSTR);
+	spin_unlock_irqrestore(&tpd->tpu->lock, flags);
+}
+
+static int tpu_pwm_timer_start(struct tpu_pwm_device *tpd)
+{
+	int ret;
+
+	if (!tpd->timer_on) {
+		/* Wake up device and enable clock. */
+		pm_runtime_get_sync(&tpd->tpu->pdev->dev);
+		ret = clk_prepare_enable(tpd->tpu->clk);
+		if (ret) {
+			dev_err(&tpd->tpu->pdev->dev, "cannot enable clock\n");
+			return ret;
+		}
+		tpd->timer_on = true;
+	}
+
+	/*
+	 * Make sure the channel is stopped, as we need to reconfigure it
+	 * completely. First drive the pin to the inactive state to avoid
+	 * glitches.
+	 */
+	tpu_pwm_set_pin(tpd, TPU_PIN_INACTIVE);
+	tpu_pwm_start_stop(tpd, false);
+
+	/*
+	 * - Clear TCNT on TGRB match
+	 * - Count on rising edge
+	 * - Set prescaler
+	 * - Output 0 until TGRA, output 1 until TGRB (active low polarity)
+	 * - Output 1 until TGRA, output 0 until TGRB (active high polarity
+	 * - PWM mode
+	 */
+	tpu_pwm_write(tpd, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING |
+		      tpd->prescaler);
+	tpu_pwm_write(tpd, TPU_TMDRn, TPU_TMDR_MD_PWM);
+	tpu_pwm_set_pin(tpd, TPU_PIN_PWM);
+	tpu_pwm_write(tpd, TPU_TGRAn, tpd->duty);
+	tpu_pwm_write(tpd, TPU_TGRBn, tpd->period);
+
+	dev_dbg(&tpd->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n",
+		tpd->channel, tpd->duty, tpd->period);
+
+	/* Start the channel. */
+	tpu_pwm_start_stop(tpd, true);
+
+	return 0;
+}
+
+static void tpu_pwm_timer_stop(struct tpu_pwm_device *tpd)
+{
+	if (!tpd->timer_on)
+		return;
+
+	/* Disable channel. */
+	tpu_pwm_start_stop(tpd, false);
+
+	/* Stop clock and mark device as idle. */
+	clk_disable_unprepare(tpd->tpu->clk);
+	pm_runtime_put(&tpd->tpu->pdev->dev);
+
+	tpd->timer_on = false;
+}
+
+/* -----------------------------------------------------------------------------
+ * PWM API
+ */
+
+static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct tpu_device *tpu = to_tpu_device(chip);
+	struct tpu_pwm_device *tpd;
+
+	if (pwm->hwpwm >= TPU_CHANNEL_MAX)
+		return -EINVAL;
+
+	tpd = kzalloc(sizeof(*tpd), GFP_KERNEL);
+	if (tpd == NULL)
+		return -ENOMEM;
+
+	tpd->tpu = tpu;
+	tpd->channel = pwm->hwpwm;
+	tpd->polarity = PWM_POLARITY_NORMAL;
+	tpd->prescaler = 0;
+	tpd->period = 0;
+	tpd->duty = 0;
+
+	tpd->timer_on = false;
+
+	pwm_set_chip_data(pwm, tpd);
+
+	return 0;
+}
+
+static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct tpu_pwm_device *tpd = pwm_get_chip_data(pwm);
+
+	tpu_pwm_timer_stop(tpd);
+	kfree(tpd);
+}
+
+static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  u64 duty_ns, u64 period_ns, bool enabled)
+{
+	struct tpu_pwm_device *tpd = pwm_get_chip_data(pwm);
+	struct tpu_device *tpu = to_tpu_device(chip);
+	unsigned int prescaler;
+	bool duty_only = false;
+	u32 clk_rate;
+	u64 period;
+	u32 duty;
+	int ret;
+
+	clk_rate = clk_get_rate(tpu->clk);
+	if (unlikely(clk_rate > NSEC_PER_SEC)) {
+		/*
+		 * This won't happen in the nearer future, so this is only a
+		 * safeguard to prevent the following calculation from
+		 * overflowing. With this clk_rate * period_ns / NSEC_PER_SEC is
+		 * not greater than period_ns and so fits into an u64.
+		 */
+		return -EINVAL;
+	}
+
+	period = mul_u64_u64_div_u64(clk_rate, period_ns, NSEC_PER_SEC);
+
+	/*
+	 * Find the minimal prescaler in [0..3] such that
+	 *
+	 *     period >> (2 * prescaler) < 0x10000
+	 *
+	 * This could be calculated using something like:
+	 *
+	 *     prescaler = max(ilog2(period) / 2, 7) - 7;
+	 *
+	 * but given there are only four allowed results and that ilog2 isn't
+	 * cheap on all platforms using a switch statement is more effective.
+	 */
+	switch (period) {
+	case 1 ... 0xffff:
+		prescaler = 0;
+		break;
+
+	case 0x10000 ... 0x3ffff:
+		prescaler = 1;
+		break;
+
+	case 0x40000 ... 0xfffff:
+		prescaler = 2;
+		break;
+
+	case 0x100000 ... 0x3fffff:
+		prescaler = 3;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	period >>= 2 * prescaler;
+
+	if (duty_ns)
+		duty = mul_u64_u64_div_u64(clk_rate, duty_ns,
+					   (u64)NSEC_PER_SEC << (2 * prescaler));
+	else
+		duty = 0;
+
+	dev_dbg(&tpu->pdev->dev,
+		"rate %u, prescaler %u, period %u, duty %u\n",
+		clk_rate, 1 << (2 * prescaler), (u32)period, duty);
+
+	if (tpd->prescaler == prescaler && tpd->period == period)
+		duty_only = true;
+
+	tpd->prescaler = prescaler;
+	tpd->period = period;
+	tpd->duty = duty;
+
+	/* If the channel is disabled we're done. */
+	if (!enabled)
+		return 0;
+
+	if (duty_only && tpd->timer_on) {
+		/*
+		 * If only the duty cycle changed and the timer is already
+		 * running, there's no need to reconfigure it completely, Just
+		 * modify the duty cycle.
+		 */
+		tpu_pwm_write(tpd, TPU_TGRAn, tpd->duty);
+		dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", tpd->channel,
+			tpd->duty);
+	} else {
+		/* Otherwise perform a full reconfiguration. */
+		ret = tpu_pwm_timer_start(tpd);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (duty == 0 || duty == period) {
+		/*
+		 * To avoid running the timer when not strictly required, handle
+		 * 0% and 100% duty cycles as fixed levels and stop the timer.
+		 */
+		tpu_pwm_set_pin(tpd, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
+		tpu_pwm_timer_stop(tpd);
+	}
+
+	return 0;
+}
+
+static int tpu_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+				enum pwm_polarity polarity)
+{
+	struct tpu_pwm_device *tpd = pwm_get_chip_data(pwm);
+
+	tpd->polarity = polarity;
+
+	return 0;
+}
+
+static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct tpu_pwm_device *tpd = pwm_get_chip_data(pwm);
+	int ret;
+
+	ret = tpu_pwm_timer_start(tpd);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * To avoid running the timer when not strictly required, handle 0% and
+	 * 100% duty cycles as fixed levels and stop the timer.
+	 */
+	if (tpd->duty == 0 || tpd->duty == tpd->period) {
+		tpu_pwm_set_pin(tpd, tpd->duty ?
+				TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
+		tpu_pwm_timer_stop(tpd);
+	}
+
+	return 0;
+}
+
+static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct tpu_pwm_device *tpd = pwm_get_chip_data(pwm);
+
+	/* The timer must be running to modify the pin output configuration. */
+	tpu_pwm_timer_start(tpd);
+	tpu_pwm_set_pin(tpd, TPU_PIN_INACTIVE);
+	tpu_pwm_timer_stop(tpd);
+}
+
+static int tpu_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) {
+			tpu_pwm_disable(chip, pwm);
+			enabled = false;
+		}
+
+		err = tpu_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			tpu_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = tpu_pwm_config(pwm->chip, pwm,
+			     state->duty_cycle, state->period, enabled);
+	if (err)
+		return err;
+
+	if (!enabled)
+		err = tpu_pwm_enable(chip, pwm);
+
+	return err;
+}
+
+static const struct pwm_ops tpu_pwm_ops = {
+	.request = tpu_pwm_request,
+	.free = tpu_pwm_free,
+	.apply = tpu_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe and remove
+ */
+
+static int tpu_probe(struct platform_device *pdev)
+{
+	struct tpu_device *tpu;
+	int ret;
+
+	tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
+	if (tpu == NULL)
+		return -ENOMEM;
+
+	spin_lock_init(&tpu->lock);
+	tpu->pdev = pdev;
+
+	/* Map memory, get clock and pin control. */
+	tpu->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tpu->base))
+		return PTR_ERR(tpu->base);
+
+	tpu->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(tpu->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(tpu->clk), "Failed to get clock\n");
+
+	/* Initialize and register the device. */
+	platform_set_drvdata(pdev, tpu);
+
+	tpu->chip.dev = &pdev->dev;
+	tpu->chip.ops = &tpu_pwm_ops;
+	tpu->chip.npwm = TPU_CHANNEL_MAX;
+
+	ret = devm_pm_runtime_enable(&pdev->dev);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "Failed to enable runtime PM\n");
+
+	ret = devm_pwmchip_add(&pdev->dev, &tpu->chip);
+	if (ret < 0)
+		return dev_err_probe(&pdev->dev, ret, "Failed to register PWM chip\n");
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id tpu_of_table[] = {
+	{ .compatible = "renesas,tpu-r8a73a4", },
+	{ .compatible = "renesas,tpu-r8a7740", },
+	{ .compatible = "renesas,tpu-r8a7790", },
+	{ .compatible = "renesas,tpu", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, tpu_of_table);
+#endif
+
+static struct platform_driver tpu_driver = {
+	.probe		= tpu_probe,
+	.driver		= {
+		.name	= "renesas-tpu-pwm",
+		.of_match_table = of_match_ptr(tpu_of_table),
+	}
+};
+
+module_platform_driver(tpu_driver);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
+MODULE_DESCRIPTION("Renesas TPU PWM Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:renesas-tpu-pwm");