1 files changed, 335 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
new file mode 100644
index 000000000..4701f0c9b
--- /dev/null
+++ b/drivers/pwm/pwm-tiecap.c
@@ -0,0 +1,335 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ECAP PWM driver
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+
+/* ECAP registers and bits definitions */
+#define CAP1			0x08
+#define CAP2			0x0C
+#define CAP3			0x10
+#define CAP4			0x14
+#define ECCTL2			0x2A
+#define ECCTL2_APWM_POL_LOW	BIT(10)
+#define ECCTL2_APWM_MODE	BIT(9)
+#define ECCTL2_SYNC_SEL_DISA	(BIT(7) | BIT(6))
+#define ECCTL2_TSCTR_FREERUN	BIT(4)
+
+struct ecap_context {
+	u32 cap3;
+	u32 cap4;
+	u16 ecctl2;
+};
+
+struct ecap_pwm_chip {
+	struct pwm_chip chip;
+	unsigned int clk_rate;
+	void __iomem *mmio_base;
+	struct ecap_context ctx;
+};
+
+static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct ecap_pwm_chip, chip);
+}
+
+/*
+ * period_ns = 10^9 * period_cycles / PWM_CLK_RATE
+ * duty_ns   = 10^9 * duty_cycles / PWM_CLK_RATE
+ */
+static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			   int duty_ns, int period_ns, int enabled)
+{
+	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+	u32 period_cycles, duty_cycles;
+	unsigned long long c;
+	u16 value;
+
+	c = pc->clk_rate;
+	c = c * period_ns;
+	do_div(c, NSEC_PER_SEC);
+	period_cycles = (u32)c;
+
+	if (period_cycles < 1) {
+		period_cycles = 1;
+		duty_cycles = 1;
+	} else {
+		c = pc->clk_rate;
+		c = c * duty_ns;
+		do_div(c, NSEC_PER_SEC);
+		duty_cycles = (u32)c;
+	}
+
+	pm_runtime_get_sync(pc->chip.dev);
+
+	value = readw(pc->mmio_base + ECCTL2);
+
+	/* Configure APWM mode & disable sync option */
+	value |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
+
+	writew(value, pc->mmio_base + ECCTL2);
+
+	if (!enabled) {
+		/* Update active registers if not running */
+		writel(duty_cycles, pc->mmio_base + CAP2);
+		writel(period_cycles, pc->mmio_base + CAP1);
+	} else {
+		/*
+		 * Update shadow registers to configure period and
+		 * compare values. This helps current PWM period to
+		 * complete on reconfiguring
+		 */
+		writel(duty_cycles, pc->mmio_base + CAP4);
+		writel(period_cycles, pc->mmio_base + CAP3);
+	}
+
+	if (!enabled) {
+		value = readw(pc->mmio_base + ECCTL2);
+		/* Disable APWM mode to put APWM output Low */
+		value &= ~ECCTL2_APWM_MODE;
+		writew(value, pc->mmio_base + ECCTL2);
+	}
+
+	pm_runtime_put_sync(pc->chip.dev);
+
+	return 0;
+}
+
+static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+				 enum pwm_polarity polarity)
+{
+	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+	u16 value;
+
+	pm_runtime_get_sync(pc->chip.dev);
+
+	value = readw(pc->mmio_base + ECCTL2);
+
+	if (polarity == PWM_POLARITY_INVERSED)
+		/* Duty cycle defines LOW period of PWM */
+		value |= ECCTL2_APWM_POL_LOW;
+	else
+		/* Duty cycle defines HIGH period of PWM */
+		value &= ~ECCTL2_APWM_POL_LOW;
+
+	writew(value, pc->mmio_base + ECCTL2);
+
+	pm_runtime_put_sync(pc->chip.dev);
+
+	return 0;
+}
+
+static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+	u16 value;
+
+	/* Leave clock enabled on enabling PWM */
+	pm_runtime_get_sync(pc->chip.dev);
+
+	/*
+	 * Enable 'Free run Time stamp counter mode' to start counter
+	 * and  'APWM mode' to enable APWM output
+	 */
+	value = readw(pc->mmio_base + ECCTL2);
+	value |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
+	writew(value, pc->mmio_base + ECCTL2);
+
+	return 0;
+}
+
+static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+	u16 value;
+
+	/*
+	 * Disable 'Free run Time stamp counter mode' to stop counter
+	 * and 'APWM mode' to put APWM output to low
+	 */
+	value = readw(pc->mmio_base + ECCTL2);
+	value &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
+	writew(value, pc->mmio_base + ECCTL2);
+
+	/* Disable clock on PWM disable */
+	pm_runtime_put_sync(pc->chip.dev);
+}
+
+static int ecap_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			  const struct pwm_state *state)
+{
+	int err;
+	int enabled = pwm->state.enabled;
+
+	if (state->polarity != pwm->state.polarity) {
+
+		if (enabled) {
+			ecap_pwm_disable(chip, pwm);
+			enabled = false;
+		}
+
+		err = ecap_pwm_set_polarity(chip, pwm, state->polarity);
+		if (err)
+			return err;
+	}
+
+	if (!state->enabled) {
+		if (enabled)
+			ecap_pwm_disable(chip, pwm);
+		return 0;
+	}
+
+	if (state->period > NSEC_PER_SEC)
+		return -ERANGE;
+
+	err = ecap_pwm_config(chip, pwm, state->duty_cycle,
+			      state->period, enabled);
+	if (err)
+		return err;
+
+	if (!enabled)
+		return ecap_pwm_enable(chip, pwm);
+
+	return 0;
+}
+
+static const struct pwm_ops ecap_pwm_ops = {
+	.apply = ecap_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id ecap_of_match[] = {
+	{ .compatible	= "ti,am3352-ecap" },
+	{ .compatible	= "ti,am33xx-ecap" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ecap_of_match);
+
+static int ecap_pwm_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct ecap_pwm_chip *pc;
+	struct clk *clk;
+	int ret;
+
+	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
+	if (!pc)
+		return -ENOMEM;
+
+	clk = devm_clk_get(&pdev->dev, "fck");
+	if (IS_ERR(clk)) {
+		if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
+			dev_warn(&pdev->dev, "Binding is obsolete.\n");
+			clk = devm_clk_get(pdev->dev.parent, "fck");
+		}
+	}
+
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "failed to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	pc->clk_rate = clk_get_rate(clk);
+	if (!pc->clk_rate) {
+		dev_err(&pdev->dev, "failed to get clock rate\n");
+		return -EINVAL;
+	}
+
+	pc->chip.dev = &pdev->dev;
+	pc->chip.ops = &ecap_pwm_ops;
+	pc->chip.npwm = 1;
+
+	pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(pc->mmio_base))
+		return PTR_ERR(pc->mmio_base);
+
+	ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pc);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+}
+
+static int ecap_pwm_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
+{
+	pm_runtime_get_sync(pc->chip.dev);
+	pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
+	pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
+	pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
+	pm_runtime_put_sync(pc->chip.dev);
+}
+
+static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
+{
+	writel(pc->ctx.cap3, pc->mmio_base + CAP3);
+	writel(pc->ctx.cap4, pc->mmio_base + CAP4);
+	writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
+}
+
+static int ecap_pwm_suspend(struct device *dev)
+{
+	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
+	struct pwm_device *pwm = pc->chip.pwms;
+
+	ecap_pwm_save_context(pc);
+
+	/* Disable explicitly if PWM is running */
+	if (pwm_is_enabled(pwm))
+		pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int ecap_pwm_resume(struct device *dev)
+{
+	struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
+	struct pwm_device *pwm = pc->chip.pwms;
+
+	/* Enable explicitly if PWM was running */
+	if (pwm_is_enabled(pwm))
+		pm_runtime_get_sync(dev);
+
+	ecap_pwm_restore_context(pc);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);
+
+static struct platform_driver ecap_pwm_driver = {
+	.driver = {
+		.name = "ecap",
+		.of_match_table = ecap_of_match,
+		.pm = &ecap_pwm_pm_ops,
+	},
+	.probe = ecap_pwm_probe,
+	.remove = ecap_pwm_remove,
+};
+module_platform_driver(ecap_pwm_driver);
+
+MODULE_DESCRIPTION("ECAP PWM driver");
+MODULE_AUTHOR("Texas Instruments");
+MODULE_LICENSE("GPL");