14  * This driver adds a high-resolution timer based PWM driver. Since this is a
15  * bit-banged driver, accuracy will always depend on a lot of factors, such as
50 	enum pwm_polarity polarity = pwm_get_polarity(pc->chip.pwms);  in gpio_pwm_off()
52 	gpiod_set_value(pc->gpiod, polarity ? 1 : 0);  in gpio_pwm_off()
57 	enum pwm_polarity polarity = pwm_get_polarity(pc->chip.pwms);  in gpio_pwm_on()
59 	gpiod_set_value(pc->gpiod, polarity ? 0 : 1);  in gpio_pwm_on()
67 	if (!pwm_is_enabled(pc->chip.pwms)) {  in gpio_pwm_timer()
69 		pc->pin_on = false;  in gpio_pwm_timer()
73 	if (!pc->pin_on) {  in gpio_pwm_timer()
74 		hrtimer_forward_now(&pc->timer, ns_to_ktime(pc->on_time));  in gpio_pwm_timer()
76 		if (pc->on_time) {  in gpio_pwm_timer()
78 			pc->pin_on = true;  in gpio_pwm_timer()
82 		hrtimer_forward_now(&pc->timer, ns_to_ktime(pc->off_time));  in gpio_pwm_timer()
84 		if (pc->off_time) {  in gpio_pwm_timer()
86 			pc->pin_on = false;  in gpio_pwm_timer()
98 	pc->on_time = duty_ns;  in gpio_pwm_config()
99 	pc->off_time = period_ns - duty_ns;  in gpio_pwm_config()
114 	if (pwm_is_enabled(pc->chip.pwms))  in gpio_pwm_enable()
115 		return -EBUSY;  in gpio_pwm_enable()
117 	if (pc->off_time) {  in gpio_pwm_enable()
118 		hrtimer_start(&pc->timer, ktime_set(0, 0), HRTIMER_MODE_REL);  in gpio_pwm_enable()
120 		if (pc->on_time)  in gpio_pwm_enable()
133 	if (!pc->off_time)  in gpio_pwm_disable()
150 	pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);  in gpio_pwm_probe()
152 		return -ENOMEM;  in gpio_pwm_probe()
154 	pc->chip.dev = &pdev->dev;  in gpio_pwm_probe()
155 	pc->chip.ops = &gpio_pwm_ops;  in gpio_pwm_probe()
156 	pc->chip.base = -1;  in gpio_pwm_probe()
157 	pc->chip.npwm = 1;  in gpio_pwm_probe()
158 	pc->chip.of_xlate = of_pwm_xlate_with_flags;  in gpio_pwm_probe()
159 	pc->chip.of_pwm_n_cells = 3;  in gpio_pwm_probe()
161 	pc->gpiod = devm_gpiod_get(&pdev->dev, "pwm", GPIOD_OUT_LOW);  in gpio_pwm_probe()
163 	if (IS_ERR(pc->gpiod))  in gpio_pwm_probe()
164 		return PTR_ERR(pc->gpiod);  in gpio_pwm_probe()
166 	hrtimer_init(&pc->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  in gpio_pwm_probe()
167 	pc->timer.function = &gpio_pwm_timer;  in gpio_pwm_probe()
168 	pc->pin_on = false;  in gpio_pwm_probe()
170 	if (!hrtimer_is_hres_active(&pc->timer))  in gpio_pwm_probe()
171 		dev_warn(&pdev->dev, "HR timer unavailable, restricting to "  in gpio_pwm_probe()
174 	ret = pwmchip_add(&pc->chip);  in gpio_pwm_probe()
176 		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);  in gpio_pwm_probe()
188 	hrtimer_cancel(&pc->timer);  in gpio_pwm_remove()
189 	return pwmchip_remove(&pc->chip);  in gpio_pwm_remove()
194 	{ .compatible = "pwm-gpio", },
204 		.name = "pwm-gpio",
211 MODULE_DESCRIPTION("Generic GPIO bit-banged PWM driver");