1 files changed, 433 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
new file mode 100644
index 000000000..0fccf061a
--- /dev/null
+++ b/drivers/pwm/pwm-img.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Imagination Technologies Pulse Width Modulator driver
+ *
+ * Copyright (c) 2014-2015, Imagination Technologies
+ *
+ * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* PWM registers */
+#define PWM_CTRL_CFG				0x0000
+#define PWM_CTRL_CFG_NO_SUB_DIV			0
+#define PWM_CTRL_CFG_SUB_DIV0			1
+#define PWM_CTRL_CFG_SUB_DIV1			2
+#define PWM_CTRL_CFG_SUB_DIV0_DIV1		3
+#define PWM_CTRL_CFG_DIV_SHIFT(ch)		((ch) * 2 + 4)
+#define PWM_CTRL_CFG_DIV_MASK			0x3
+
+#define PWM_CH_CFG(ch)				(0x4 + (ch) * 4)
+#define PWM_CH_CFG_TMBASE_SHIFT			0
+#define PWM_CH_CFG_DUTY_SHIFT			16
+
+#define PERIP_PWM_PDM_CONTROL			0x0140
+#define PERIP_PWM_PDM_CONTROL_CH_MASK		0x1
+#define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch)	((ch) * 4)
+
+#define IMG_PWM_PM_TIMEOUT			1000 /* ms */
+
+/*
+ * PWM period is specified with a timebase register,
+ * in number of step periods. The PWM duty cycle is also
+ * specified in step periods, in the [0, $timebase] range.
+ * In other words, the timebase imposes the duty cycle
+ * resolution. Therefore, let's constraint the timebase to
+ * a minimum value to allow a sane range of duty cycle values.
+ * Imposing a minimum timebase, will impose a maximum PWM frequency.
+ *
+ * The value chosen is completely arbitrary.
+ */
+#define MIN_TMBASE_STEPS			16
+
+#define IMG_PWM_NPWM				4
+
+struct img_pwm_soc_data {
+	u32 max_timebase;
+};
+
+struct img_pwm_chip {
+	struct device	*dev;
+	struct pwm_chip	chip;
+	struct clk	*pwm_clk;
+	struct clk	*sys_clk;
+	void __iomem	*base;
+	struct regmap	*periph_regs;
+	int		max_period_ns;
+	int		min_period_ns;
+	const struct img_pwm_soc_data   *data;
+	u32		suspend_ctrl_cfg;
+	u32		suspend_ch_cfg[IMG_PWM_NPWM];
+};
+
+static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct img_pwm_chip, chip);
+}
+
+static inline void img_pwm_writel(struct img_pwm_chip *imgchip,
+				  u32 reg, u32 val)
+{
+	writel(val, imgchip->base + reg);
+}
+
+static inline u32 img_pwm_readl(struct img_pwm_chip *imgchip, u32 reg)
+{
+	return readl(imgchip->base + reg);
+}
+
+static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  int duty_ns, int period_ns)
+{
+	u32 val, div, duty, timebase;
+	unsigned long mul, output_clk_hz, input_clk_hz;
+	struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
+	unsigned int max_timebase = imgchip->data->max_timebase;
+	int ret;
+
+	if (period_ns < imgchip->min_period_ns ||
+	    period_ns > imgchip->max_period_ns) {
+		dev_err(chip->dev, "configured period not in range\n");
+		return -ERANGE;
+	}
+
+	input_clk_hz = clk_get_rate(imgchip->pwm_clk);
+	output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
+
+	mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
+	if (mul <= max_timebase) {
+		div = PWM_CTRL_CFG_NO_SUB_DIV;
+		timebase = DIV_ROUND_UP(mul, 1);
+	} else if (mul <= max_timebase * 8) {
+		div = PWM_CTRL_CFG_SUB_DIV0;
+		timebase = DIV_ROUND_UP(mul, 8);
+	} else if (mul <= max_timebase * 64) {
+		div = PWM_CTRL_CFG_SUB_DIV1;
+		timebase = DIV_ROUND_UP(mul, 64);
+	} else if (mul <= max_timebase * 512) {
+		div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
+		timebase = DIV_ROUND_UP(mul, 512);
+	} else {
+		dev_err(chip->dev,
+			"failed to configure timebase steps/divider value\n");
+		return -EINVAL;
+	}
+
+	duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
+
+	ret = pm_runtime_resume_and_get(chip->dev);
+	if (ret < 0)
+		return ret;
+
+	val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
+	val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
+	val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
+		PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
+	img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
+
+	val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
+	      (timebase << PWM_CH_CFG_TMBASE_SHIFT);
+	img_pwm_writel(imgchip, PWM_CH_CFG(pwm->hwpwm), val);
+
+	pm_runtime_mark_last_busy(chip->dev);
+	pm_runtime_put_autosuspend(chip->dev);
+
+	return 0;
+}
+
+static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 val;
+	struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
+	int ret;
+
+	ret = pm_runtime_resume_and_get(chip->dev);
+	if (ret < 0)
+		return ret;
+
+	val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
+	val |= BIT(pwm->hwpwm);
+	img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
+
+	regmap_update_bits(imgchip->periph_regs, PERIP_PWM_PDM_CONTROL,
+			   PERIP_PWM_PDM_CONTROL_CH_MASK <<
+			   PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm), 0);
+
+	return 0;
+}
+
+static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 val;
+	struct img_pwm_chip *imgchip = to_img_pwm_chip(chip);
+
+	val = img_pwm_readl(imgchip, PWM_CTRL_CFG);
+	val &= ~BIT(pwm->hwpwm);
+	img_pwm_writel(imgchip, PWM_CTRL_CFG, val);
+
+	pm_runtime_mark_last_busy(chip->dev);
+	pm_runtime_put_autosuspend(chip->dev);
+}
+
+static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			 const struct pwm_state *state)
+{
+	int err;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (!state->enabled) {
+		if (pwm->state.enabled)
+			img_pwm_disable(chip, pwm);
+
+		return 0;
+	}
+
+	err = img_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
+	if (err)
+		return err;
+
+	if (!pwm->state.enabled)
+		err = img_pwm_enable(chip, pwm);
+
+	return err;
+}
+
+static const struct pwm_ops img_pwm_ops = {
+	.apply = img_pwm_apply,
+	.owner = THIS_MODULE,
+};
+
+static const struct img_pwm_soc_data pistachio_pwm = {
+	.max_timebase = 255,
+};
+
+static const struct of_device_id img_pwm_of_match[] = {
+	{
+		.compatible = "img,pistachio-pwm",
+		.data = &pistachio_pwm,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, img_pwm_of_match);
+
+static int img_pwm_runtime_suspend(struct device *dev)
+{
+	struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(imgchip->pwm_clk);
+	clk_disable_unprepare(imgchip->sys_clk);
+
+	return 0;
+}
+
+static int img_pwm_runtime_resume(struct device *dev)
+{
+	struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(imgchip->sys_clk);
+	if (ret < 0) {
+		dev_err(dev, "could not prepare or enable sys clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(imgchip->pwm_clk);
+	if (ret < 0) {
+		dev_err(dev, "could not prepare or enable pwm clock\n");
+		clk_disable_unprepare(imgchip->sys_clk);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int img_pwm_probe(struct platform_device *pdev)
+{
+	int ret;
+	u64 val;
+	unsigned long clk_rate;
+	struct img_pwm_chip *imgchip;
+	const struct of_device_id *of_dev_id;
+
+	imgchip = devm_kzalloc(&pdev->dev, sizeof(*imgchip), GFP_KERNEL);
+	if (!imgchip)
+		return -ENOMEM;
+
+	imgchip->dev = &pdev->dev;
+
+	imgchip->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(imgchip->base))
+		return PTR_ERR(imgchip->base);
+
+	of_dev_id = of_match_device(img_pwm_of_match, &pdev->dev);
+	if (!of_dev_id)
+		return -ENODEV;
+	imgchip->data = of_dev_id->data;
+
+	imgchip->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+							       "img,cr-periph");
+	if (IS_ERR(imgchip->periph_regs))
+		return PTR_ERR(imgchip->periph_regs);
+
+	imgchip->sys_clk = devm_clk_get(&pdev->dev, "sys");
+	if (IS_ERR(imgchip->sys_clk)) {
+		dev_err(&pdev->dev, "failed to get system clock\n");
+		return PTR_ERR(imgchip->sys_clk);
+	}
+
+	imgchip->pwm_clk = devm_clk_get(&pdev->dev, "imgchip");
+	if (IS_ERR(imgchip->pwm_clk)) {
+		dev_err(&pdev->dev, "failed to get imgchip clock\n");
+		return PTR_ERR(imgchip->pwm_clk);
+	}
+
+	platform_set_drvdata(pdev, imgchip);
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	if (!pm_runtime_enabled(&pdev->dev)) {
+		ret = img_pwm_runtime_resume(&pdev->dev);
+		if (ret)
+			goto err_pm_disable;
+	}
+
+	clk_rate = clk_get_rate(imgchip->pwm_clk);
+	if (!clk_rate) {
+		dev_err(&pdev->dev, "imgchip clock has no frequency\n");
+		ret = -EINVAL;
+		goto err_suspend;
+	}
+
+	/* The maximum input clock divider is 512 */
+	val = (u64)NSEC_PER_SEC * 512 * imgchip->data->max_timebase;
+	do_div(val, clk_rate);
+	imgchip->max_period_ns = val;
+
+	val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS;
+	do_div(val, clk_rate);
+	imgchip->min_period_ns = val;
+
+	imgchip->chip.dev = &pdev->dev;
+	imgchip->chip.ops = &img_pwm_ops;
+	imgchip->chip.npwm = IMG_PWM_NPWM;
+
+	ret = pwmchip_add(&imgchip->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
+		goto err_suspend;
+	}
+
+	return 0;
+
+err_suspend:
+	if (!pm_runtime_enabled(&pdev->dev))
+		img_pwm_runtime_suspend(&pdev->dev);
+err_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	return ret;
+}
+
+static int img_pwm_remove(struct platform_device *pdev)
+{
+	struct img_pwm_chip *imgchip = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		img_pwm_runtime_suspend(&pdev->dev);
+
+	pwmchip_remove(&imgchip->chip);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int img_pwm_suspend(struct device *dev)
+{
+	struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
+	int i, ret;
+
+	if (pm_runtime_status_suspended(dev)) {
+		ret = img_pwm_runtime_resume(dev);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < imgchip->chip.npwm; i++)
+		imgchip->suspend_ch_cfg[i] = img_pwm_readl(imgchip,
+							   PWM_CH_CFG(i));
+
+	imgchip->suspend_ctrl_cfg = img_pwm_readl(imgchip, PWM_CTRL_CFG);
+
+	img_pwm_runtime_suspend(dev);
+
+	return 0;
+}
+
+static int img_pwm_resume(struct device *dev)
+{
+	struct img_pwm_chip *imgchip = dev_get_drvdata(dev);
+	int ret;
+	int i;
+
+	ret = img_pwm_runtime_resume(dev);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < imgchip->chip.npwm; i++)
+		img_pwm_writel(imgchip, PWM_CH_CFG(i),
+			       imgchip->suspend_ch_cfg[i]);
+
+	img_pwm_writel(imgchip, PWM_CTRL_CFG, imgchip->suspend_ctrl_cfg);
+
+	for (i = 0; i < imgchip->chip.npwm; i++)
+		if (imgchip->suspend_ctrl_cfg & BIT(i))
+			regmap_update_bits(imgchip->periph_regs,
+					   PERIP_PWM_PDM_CONTROL,
+					   PERIP_PWM_PDM_CONTROL_CH_MASK <<
+					   PERIP_PWM_PDM_CONTROL_CH_SHIFT(i),
+					   0);
+
+	if (pm_runtime_status_suspended(dev))
+		img_pwm_runtime_suspend(dev);
+
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops img_pwm_pm_ops = {
+	SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend,
+			   img_pwm_runtime_resume,
+			   NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume)
+};
+
+static struct platform_driver img_pwm_driver = {
+	.driver = {
+		.name = "img-pwm",
+		.pm = &img_pwm_pm_ops,
+		.of_match_table = img_pwm_of_match,
+	},
+	.probe = img_pwm_probe,
+	.remove = img_pwm_remove,
+};
+module_platform_driver(img_pwm_driver);
+
+MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
+MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
+MODULE_LICENSE("GPL v2");