1 files changed, 282 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
new file mode 100644
index 0000000000..7758d274a2
--- /dev/null
+++ b/drivers/pwm/pwm-jz4740.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 platform PWM support
+ *
+ * Limitations:
+ * - The .apply callback doesn't complete the currently running period before
+ *   reconfiguring the hardware.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/mfd/ingenic-tcu.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+
+struct soc_info {
+	unsigned int num_pwms;
+};
+
+struct jz4740_pwm_chip {
+	struct pwm_chip chip;
+	struct regmap *map;
+};
+
+static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
+{
+	return container_of(chip, struct jz4740_pwm_chip, chip);
+}
+
+static bool jz4740_pwm_can_use_chn(struct jz4740_pwm_chip *jz,
+				   unsigned int channel)
+{
+	/* Enable all TCU channels for PWM use by default except channels 0/1 */
+	u32 pwm_channels_mask = GENMASK(jz->chip.npwm - 1, 2);
+
+	device_property_read_u32(jz->chip.dev->parent,
+				 "ingenic,pwm-channels-mask",
+				 &pwm_channels_mask);
+
+	return !!(pwm_channels_mask & BIT(channel));
+}
+
+static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct jz4740_pwm_chip *jz = to_jz4740(chip);
+	struct clk *clk;
+	char name[16];
+	int err;
+
+	if (!jz4740_pwm_can_use_chn(jz, pwm->hwpwm))
+		return -EBUSY;
+
+	snprintf(name, sizeof(name), "timer%u", pwm->hwpwm);
+
+	clk = clk_get(chip->dev, name);
+	if (IS_ERR(clk)) {
+		dev_err(chip->dev, "error %pe: Failed to get clock\n", clk);
+		return PTR_ERR(clk);
+	}
+
+	err = clk_prepare_enable(clk);
+	if (err < 0) {
+		clk_put(clk);
+		return err;
+	}
+
+	pwm_set_chip_data(pwm, clk);
+
+	return 0;
+}
+
+static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct clk *clk = pwm_get_chip_data(pwm);
+
+	clk_disable_unprepare(clk);
+	clk_put(clk);
+}
+
+static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct jz4740_pwm_chip *jz = to_jz4740(chip);
+
+	/* Enable PWM output */
+	regmap_set_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
+
+	/* Start counter */
+	regmap_write(jz->map, TCU_REG_TESR, BIT(pwm->hwpwm));
+
+	return 0;
+}
+
+static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct jz4740_pwm_chip *jz = to_jz4740(chip);
+
+	/*
+	 * Set duty > period. This trick allows the TCU channels in TCU2 mode to
+	 * properly return to their init level.
+	 */
+	regmap_write(jz->map, TCU_REG_TDHRc(pwm->hwpwm), 0xffff);
+	regmap_write(jz->map, TCU_REG_TDFRc(pwm->hwpwm), 0x0);
+
+	/*
+	 * Disable PWM output.
+	 * In TCU2 mode (channel 1/2 on JZ4750+), this must be done before the
+	 * counter is stopped, while in TCU1 mode the order does not matter.
+	 */
+	regmap_clear_bits(jz->map, TCU_REG_TCSRc(pwm->hwpwm), TCU_TCSR_PWM_EN);
+
+	/* Stop counter */
+	regmap_write(jz->map, TCU_REG_TECR, BIT(pwm->hwpwm));
+}
+
+static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
+	unsigned long long tmp = 0xffffull * NSEC_PER_SEC;
+	struct clk *clk = pwm_get_chip_data(pwm);
+	unsigned long period, duty;
+	long rate;
+	int err;
+
+	/*
+	 * Limit the clock to a maximum rate that still gives us a period value
+	 * which fits in 16 bits.
+	 */
+	do_div(tmp, state->period);
+
+	/*
+	 * /!\ IMPORTANT NOTE:
+	 * -------------------
+	 * This code relies on the fact that clk_round_rate() will always round
+	 * down, which is not a valid assumption given by the clk API, but only
+	 * happens to be true with the clk drivers used for Ingenic SoCs.
+	 *
+	 * Right now, there is no alternative as the clk API does not have a
+	 * round-down function (and won't have one for a while), but if it ever
+	 * comes to light, a round-down function should be used instead.
+	 */
+	rate = clk_round_rate(clk, tmp);
+	if (rate < 0) {
+		dev_err(chip->dev, "Unable to round rate: %ld", rate);
+		return rate;
+	}
+
+	/* Calculate period value */
+	tmp = (unsigned long long)rate * state->period;
+	do_div(tmp, NSEC_PER_SEC);
+	period = tmp;
+
+	/* Calculate duty value */
+	tmp = (unsigned long long)rate * state->duty_cycle;
+	do_div(tmp, NSEC_PER_SEC);
+	duty = tmp;
+
+	if (duty >= period)
+		duty = period - 1;
+
+	jz4740_pwm_disable(chip, pwm);
+
+	err = clk_set_rate(clk, rate);
+	if (err) {
+		dev_err(chip->dev, "Unable to set rate: %d", err);
+		return err;
+	}
+
+	/* Reset counter to 0 */
+	regmap_write(jz4740->map, TCU_REG_TCNTc(pwm->hwpwm), 0);
+
+	/* Set duty */
+	regmap_write(jz4740->map, TCU_REG_TDHRc(pwm->hwpwm), duty);
+
+	/* Set period */
+	regmap_write(jz4740->map, TCU_REG_TDFRc(pwm->hwpwm), period);
+
+	/* Set abrupt shutdown */
+	regmap_set_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
+			TCU_TCSR_PWM_SD);
+
+	/*
+	 * Set polarity.
+	 *
+	 * The PWM starts in inactive state until the internal timer reaches the
+	 * duty value, then becomes active until the timer reaches the period
+	 * value. In theory, we should then use (period - duty) as the real duty
+	 * value, as a high duty value would otherwise result in the PWM pin
+	 * being inactive most of the time.
+	 *
+	 * Here, we don't do that, and instead invert the polarity of the PWM
+	 * when it is active. This trick makes the PWM start with its active
+	 * state instead of its inactive state.
+	 */
+	if ((state->polarity == PWM_POLARITY_NORMAL) ^ state->enabled)
+		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
+				   TCU_TCSR_PWM_INITL_HIGH, 0);
+	else
+		regmap_update_bits(jz4740->map, TCU_REG_TCSRc(pwm->hwpwm),
+				   TCU_TCSR_PWM_INITL_HIGH,
+				   TCU_TCSR_PWM_INITL_HIGH);
+
+	if (state->enabled)
+		jz4740_pwm_enable(chip, pwm);
+
+	return 0;
+}
+
+static const struct pwm_ops jz4740_pwm_ops = {
+	.request = jz4740_pwm_request,
+	.free = jz4740_pwm_free,
+	.apply = jz4740_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+static int jz4740_pwm_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct jz4740_pwm_chip *jz4740;
+	const struct soc_info *info;
+
+	info = device_get_match_data(dev);
+	if (!info)
+		return -EINVAL;
+
+	jz4740 = devm_kzalloc(dev, sizeof(*jz4740), GFP_KERNEL);
+	if (!jz4740)
+		return -ENOMEM;
+
+	jz4740->map = device_node_to_regmap(dev->parent->of_node);
+	if (IS_ERR(jz4740->map)) {
+		dev_err(dev, "regmap not found: %ld\n", PTR_ERR(jz4740->map));
+		return PTR_ERR(jz4740->map);
+	}
+
+	jz4740->chip.dev = dev;
+	jz4740->chip.ops = &jz4740_pwm_ops;
+	jz4740->chip.npwm = info->num_pwms;
+
+	return devm_pwmchip_add(dev, &jz4740->chip);
+}
+
+static const struct soc_info jz4740_soc_info = {
+	.num_pwms = 8,
+};
+
+static const struct soc_info jz4725b_soc_info = {
+	.num_pwms = 6,
+};
+
+static const struct soc_info x1000_soc_info = {
+	.num_pwms = 5,
+};
+
+static const struct of_device_id jz4740_pwm_dt_ids[] = {
+	{ .compatible = "ingenic,jz4740-pwm", .data = &jz4740_soc_info },
+	{ .compatible = "ingenic,jz4725b-pwm", .data = &jz4725b_soc_info },
+	{ .compatible = "ingenic,x1000-pwm", .data = &x1000_soc_info },
+	{},
+};
+MODULE_DEVICE_TABLE(of, jz4740_pwm_dt_ids);
+
+static struct platform_driver jz4740_pwm_driver = {
+	.driver = {
+		.name = "jz4740-pwm",
+		.of_match_table = jz4740_pwm_dt_ids,
+	},
+	.probe = jz4740_pwm_probe,
+};
+module_platform_driver(jz4740_pwm_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver");
+MODULE_ALIAS("platform:jz4740-pwm");
+MODULE_LICENSE("GPL");