1 // SPDX-License-Identifier: GPL-2.0-only
3  * Copyright (C) 2017-2025 Loongson Technology Corporation Limited.
5  * Loongson PWM driver
7  * For Loongson's PWM IP block documentation please refer Chapter 11 of
8 …* Reference Manual: https://loongson.github.io/LoongArch-Documentation/Loongson-7A1000-usermanual-…
15  * - If both DUTY and PERIOD are set to 0, the output is a constant low signal.
16  * - When disabled the output is driven to 0 independent of the configured
18  * - If the register is reconfigured while PWM is running, it does not complete
20  * - Disabling the PWM stops the output immediately (without waiting for current
25 #include <linux/clk.h>
32 #include <linux/pwm.h>
35 /* Loongson PWM registers */
48 #define LOONGSON_PWM_CTRL_REG_INVERT	BIT(9)  /* Output flip-flop Enable Bit */
49 #define LOONGSON_PWM_CTRL_REG_DZONE	BIT(10) /* Anti-dead Zone Enable Bit */
51 /* default input clk frequency for the ACPI case */
55 	struct clk *clk;  member
67 	return readl(ddata->base + offset);  in pwm_loongson_readl()
73 	writel(val, ddata->base + offset);  in pwm_loongson_writel()
76 static int pwm_loongson_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,  in pwm_loongson_set_polarity()  argument
85 		/* Duty cycle defines LOW period of PWM */  in pwm_loongson_set_polarity()
88 		/* Duty cycle defines HIGH period of PWM */  in pwm_loongson_set_polarity()
96 static void pwm_loongson_disable(struct pwm_chip *chip, struct pwm_device *pwm)  in pwm_loongson_disable()  argument
106 static int pwm_loongson_enable(struct pwm_chip *chip, struct pwm_device *pwm)  in pwm_loongson_enable()  argument
118 static int pwm_loongson_config(struct pwm_chip *chip, struct pwm_device *pwm,  in pwm_loongson_config()  argument
124 	/* duty = duty_ns * ddata->clk_rate / NSEC_PER_SEC */  in pwm_loongson_config()
125 	duty = mul_u64_u64_div_u64(duty_ns, ddata->clk_rate, NSEC_PER_SEC);  in pwm_loongson_config()
129 	/* period = period_ns * ddata->clk_rate / NSEC_PER_SEC */  in pwm_loongson_config()
130 	period = mul_u64_u64_div_u64(period_ns, ddata->clk_rate, NSEC_PER_SEC);  in pwm_loongson_config()
140 static int pwm_loongson_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in pwm_loongson_apply()  argument
144 	bool enabled = pwm->state.enabled;  in pwm_loongson_apply()
146 	if (!state->enabled) {  in pwm_loongson_apply()
148 			pwm_loongson_disable(chip, pwm);  in pwm_loongson_apply()
152 	ret = pwm_loongson_set_polarity(chip, pwm, state->polarity);  in pwm_loongson_apply()
156 	ret = pwm_loongson_config(chip, pwm, state->duty_cycle, state->period);  in pwm_loongson_apply()
160 	if (!enabled && state->enabled)  in pwm_loongson_apply()
161 		ret = pwm_loongson_enable(chip, pwm);  in pwm_loongson_apply()
166 static int pwm_loongson_get_state(struct pwm_chip *chip, struct pwm_device *pwm,  in pwm_loongson_get_state()  argument
177 	state->duty_cycle = DIV64_U64_ROUND_UP((u64)duty * NSEC_PER_SEC, ddata->clk_rate);  in pwm_loongson_get_state()
178 	state->period = DIV64_U64_ROUND_UP((u64)period * NSEC_PER_SEC, ddata->clk_rate);  in pwm_loongson_get_state()
179 	state->polarity = (ctrl & LOONGSON_PWM_CTRL_REG_INVERT) ? PWM_POLARITY_INVERSED :  in pwm_loongson_get_state()
181 	state->enabled = (ctrl & LOONGSON_PWM_CTRL_REG_EN) ? true : false;  in pwm_loongson_get_state()
196 	struct device *dev = &pdev->dev;  in pwm_loongson_probe()
203 	ddata->base = devm_platform_ioremap_resource(pdev, 0);  in pwm_loongson_probe()
204 	if (IS_ERR(ddata->base))  in pwm_loongson_probe()
205 		return PTR_ERR(ddata->base);  in pwm_loongson_probe()
207 	ddata->clk = devm_clk_get_optional_enabled(dev, NULL);  in pwm_loongson_probe()
208 	if (IS_ERR(ddata->clk))  in pwm_loongson_probe()
209 		return dev_err_probe(dev, PTR_ERR(ddata->clk),  in pwm_loongson_probe()
210 				     "Failed to get pwm clock\n");  in pwm_loongson_probe()
211 	if (ddata->clk) {  in pwm_loongson_probe()
212 		ret = devm_clk_rate_exclusive_get(dev, ddata->clk);  in pwm_loongson_probe()
217 		ddata->clk_rate = clk_get_rate(ddata->clk);  in pwm_loongson_probe()
218 		if (!ddata->clk_rate)  in pwm_loongson_probe()
219 			return dev_err_probe(dev, -EINVAL,  in pwm_loongson_probe()
222 		ddata->clk_rate = LOONGSON_PWM_FREQ_DEFAULT;  in pwm_loongson_probe()
226 	if (ddata->clk_rate > NSEC_PER_SEC)  in pwm_loongson_probe()
227 		return dev_err_probe(dev, -EINVAL, "PWM clock out of range\n");  in pwm_loongson_probe()
229 	chip->ops = &pwm_loongson_ops;  in pwm_loongson_probe()
230 	chip->atomic = true;  in pwm_loongson_probe()
235 		return dev_err_probe(dev, ret, "Failed to add PWM chip\n");  in pwm_loongson_probe()
244 	struct pwm_device *pwm = &chip->pwms[0];  in pwm_loongson_suspend()  local
246 	if (pwm->state.enabled)  in pwm_loongson_suspend()
247 		return -EBUSY;  in pwm_loongson_suspend()
249 	clk_disable_unprepare(ddata->clk);  in pwm_loongson_suspend()
259 	return clk_prepare_enable(ddata->clk);  in pwm_loongson_resume()
266 	{ .compatible = "loongson,ls7a-pwm" },
280 		.name = "loongson-pwm",
288 MODULE_DESCRIPTION("Loongson PWM driver");