1 // SPDX-License-Identifier: GPL-2.0+
8  * - The period is fixed to 1 ms and is generated continuously despite changes
9  *   to the duty cycle or enable/disable state.
10  * - Changes to the duty cycle or enable/disable state take effect immediately
12  * - The device cannot generate a 0% duty cycle. For duty cycles below 1 / 256
13  *   ms, the output is disabled and relies upon an external pull-down resistor
46 	struct iqs62x_core *iqs62x = iqs620_pwm->iqs62x;  in iqs620_pwm_init()
50 		return regmap_clear_bits(iqs62x->regmap, IQS620_PWR_SETTINGS,  in iqs620_pwm_init()
53 	ret = regmap_write(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE,  in iqs620_pwm_init()
54 			   duty_scale - 1);  in iqs620_pwm_init()
58 	return regmap_set_bits(iqs62x->regmap, IQS620_PWR_SETTINGS,  in iqs620_pwm_init()
70 	if (state->polarity != PWM_POLARITY_NORMAL)  in iqs620_pwm_apply()
71 		return -EINVAL;  in iqs620_pwm_apply()
73 	if (state->period < IQS620_PWM_PERIOD_NS)  in iqs620_pwm_apply()
74 		return -EINVAL;  in iqs620_pwm_apply()
79 	 * The duty cycle generated by the device is calculated as follows:  in iqs620_pwm_apply()
84 	 * (inclusive). Therefore the lowest duty cycle the device can generate  in iqs620_pwm_apply()
87 	 * For lower duty cycles (e.g. 0), the PWM output is simply disabled to  in iqs620_pwm_apply()
88 	 * allow an external pull-down resistor to hold the GPIO3/LTX pin low.  in iqs620_pwm_apply()
90 	duty_cycle = min_t(u64, state->duty_cycle, IQS620_PWM_PERIOD_NS);  in iqs620_pwm_apply()
93 	if (!state->enabled)  in iqs620_pwm_apply()
96 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_apply()
100 		iqs620_pwm->duty_scale = duty_scale;  in iqs620_pwm_apply()
102 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_apply()
114 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_get_state()
117 	 * Since the device cannot generate a 0% duty cycle, requests to do so  in iqs620_pwm_get_state()
122 	state->enabled = iqs620_pwm->duty_scale > 0;  in iqs620_pwm_get_state()
123 	state->duty_cycle = DIV_ROUND_UP(iqs620_pwm->duty_scale *  in iqs620_pwm_get_state()
126 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_get_state()
128 	state->period = IQS620_PWM_PERIOD_NS;  in iqs620_pwm_get_state()
129 	state->polarity = PWM_POLARITY_NORMAL;  in iqs620_pwm_get_state()
146 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_notifier()
153 	ret = iqs620_pwm_init(iqs620_pwm, iqs620_pwm->duty_scale);  in iqs620_pwm_notifier()
155 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_notifier()
158 		dev_err(iqs620_pwm->chip.dev,  in iqs620_pwm_notifier()
159 			"Failed to re-initialize device: %d\n", ret);  in iqs620_pwm_notifier()
177 	ret = blocking_notifier_chain_unregister(&iqs620_pwm->iqs62x->nh,  in iqs620_pwm_notifier_unregister()
178 						 &iqs620_pwm->notifier);  in iqs620_pwm_notifier_unregister()
180 		dev_err(iqs620_pwm->chip.dev,  in iqs620_pwm_notifier_unregister()
186 	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);  in iqs620_pwm_probe()
191 	iqs620_pwm = devm_kzalloc(&pdev->dev, sizeof(*iqs620_pwm), GFP_KERNEL);  in iqs620_pwm_probe()
193 		return -ENOMEM;  in iqs620_pwm_probe()
195 	iqs620_pwm->iqs62x = iqs62x;  in iqs620_pwm_probe()
197 	ret = regmap_read(iqs62x->regmap, IQS620_PWR_SETTINGS, &val);  in iqs620_pwm_probe()
202 		ret = regmap_read(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE, &val);  in iqs620_pwm_probe()
206 		iqs620_pwm->duty_scale = val + 1;  in iqs620_pwm_probe()
209 	iqs620_pwm->chip.dev = &pdev->dev;  in iqs620_pwm_probe()
210 	iqs620_pwm->chip.ops = &iqs620_pwm_ops;  in iqs620_pwm_probe()
211 	iqs620_pwm->chip.npwm = 1;  in iqs620_pwm_probe()
213 	mutex_init(&iqs620_pwm->lock);  in iqs620_pwm_probe()
215 	iqs620_pwm->notifier.notifier_call = iqs620_pwm_notifier;  in iqs620_pwm_probe()
216 	ret = blocking_notifier_chain_register(&iqs620_pwm->iqs62x->nh,  in iqs620_pwm_probe()
217 					       &iqs620_pwm->notifier);  in iqs620_pwm_probe()
219 		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);  in iqs620_pwm_probe()
223 	ret = devm_add_action_or_reset(&pdev->dev,  in iqs620_pwm_probe()
229 	ret = devm_pwmchip_add(&pdev->dev, &iqs620_pwm->chip);  in iqs620_pwm_probe()
231 		dev_err(&pdev->dev, "Failed to add device: %d\n", ret);  in iqs620_pwm_probe()
238 		.name = "iqs620a-pwm",
247 MODULE_ALIAS("platform:iqs620a-pwm");