1 // SPDX-License-Identifier: GPL-2.0+
3  * Azoteq IQS620A PWM Generator
8  * - The period is fixed to 1 ms and is generated continuously despite changes
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
24 #include <linux/pwm.h>
44 static int iqs620_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in iqs620_pwm_apply()  argument
53 	if (state->polarity != PWM_POLARITY_NORMAL)  in iqs620_pwm_apply()
54 		return -ENOTSUPP;  in iqs620_pwm_apply()
56 	if (state->period < IQS620_PWM_PERIOD_NS)  in iqs620_pwm_apply()
57 		return -EINVAL;  in iqs620_pwm_apply()
60 	iqs62x = iqs620_pwm->iqs62x;  in iqs620_pwm_apply()
71 	 * For lower duty cycles (e.g. 0), the PWM output is simply disabled to  in iqs620_pwm_apply()
72 	 * allow an external pull-down resistor to hold the GPIO3/LTX pin low.  in iqs620_pwm_apply()
74 	duty_cycle = min_t(u64, state->duty_cycle, IQS620_PWM_PERIOD_NS);  in iqs620_pwm_apply()
77 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_apply()
79 	if (!state->enabled || !duty_scale) {  in iqs620_pwm_apply()
80 		ret = regmap_update_bits(iqs62x->regmap, IQS620_PWR_SETTINGS,  in iqs620_pwm_apply()
87 		u8 duty_val = duty_scale - 1;  in iqs620_pwm_apply()
89 		ret = regmap_write(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE,  in iqs620_pwm_apply()
94 		iqs620_pwm->duty_val = duty_val;  in iqs620_pwm_apply()
97 	if (state->enabled && duty_scale) {  in iqs620_pwm_apply()
98 		ret = regmap_update_bits(iqs62x->regmap, IQS620_PWR_SETTINGS,  in iqs620_pwm_apply()
104 	iqs620_pwm->out_en = state->enabled;  in iqs620_pwm_apply()
107 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_apply()
112 static void iqs620_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,  in iqs620_pwm_get_state()  argument
119 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_get_state()
128 	state->enabled = iqs620_pwm->out_en;  in iqs620_pwm_get_state()
129 	state->duty_cycle = DIV_ROUND_UP((iqs620_pwm->duty_val + 1) *  in iqs620_pwm_get_state()
132 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_get_state()
134 	state->period = IQS620_PWM_PERIOD_NS;  in iqs620_pwm_get_state()
149 	iqs62x = iqs620_pwm->iqs62x;  in iqs620_pwm_notifier()
151 	mutex_lock(&iqs620_pwm->lock);  in iqs620_pwm_notifier()
158 	ret = regmap_write(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE,  in iqs620_pwm_notifier()
159 			   iqs620_pwm->duty_val);  in iqs620_pwm_notifier()
163 	ret = regmap_update_bits(iqs62x->regmap, IQS620_PWR_SETTINGS,  in iqs620_pwm_notifier()
165 				 iqs620_pwm->out_en ? 0xff : 0);  in iqs620_pwm_notifier()
168 	mutex_unlock(&iqs620_pwm->lock);  in iqs620_pwm_notifier()
171 		dev_err(iqs620_pwm->chip.dev,  in iqs620_pwm_notifier()
172 			"Failed to re-initialize device: %d\n", ret);  in iqs620_pwm_notifier()
190 	ret = blocking_notifier_chain_unregister(&iqs620_pwm->iqs62x->nh,  in iqs620_pwm_notifier_unregister()
191 						 &iqs620_pwm->notifier);  in iqs620_pwm_notifier_unregister()
193 		dev_err(iqs620_pwm->chip.dev,  in iqs620_pwm_notifier_unregister()
199 	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);  in iqs620_pwm_probe()
204 	iqs620_pwm = devm_kzalloc(&pdev->dev, sizeof(*iqs620_pwm), GFP_KERNEL);  in iqs620_pwm_probe()
206 		return -ENOMEM;  in iqs620_pwm_probe()
209 	iqs620_pwm->iqs62x = iqs62x;  in iqs620_pwm_probe()
211 	ret = regmap_read(iqs62x->regmap, IQS620_PWR_SETTINGS, &val);  in iqs620_pwm_probe()
214 	iqs620_pwm->out_en = val & IQS620_PWR_SETTINGS_PWM_OUT;  in iqs620_pwm_probe()
216 	ret = regmap_read(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE, &val);  in iqs620_pwm_probe()
219 	iqs620_pwm->duty_val = val;  in iqs620_pwm_probe()
221 	iqs620_pwm->chip.dev = &pdev->dev;  in iqs620_pwm_probe()
222 	iqs620_pwm->chip.ops = &iqs620_pwm_ops;  in iqs620_pwm_probe()
223 	iqs620_pwm->chip.base = -1;  in iqs620_pwm_probe()
224 	iqs620_pwm->chip.npwm = 1;  in iqs620_pwm_probe()
226 	mutex_init(&iqs620_pwm->lock);  in iqs620_pwm_probe()
228 	iqs620_pwm->notifier.notifier_call = iqs620_pwm_notifier;  in iqs620_pwm_probe()
229 	ret = blocking_notifier_chain_register(&iqs620_pwm->iqs62x->nh,  in iqs620_pwm_probe()
230 					       &iqs620_pwm->notifier);  in iqs620_pwm_probe()
232 		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);  in iqs620_pwm_probe()
236 	ret = devm_add_action_or_reset(&pdev->dev,  in iqs620_pwm_probe()
242 	ret = pwmchip_add(&iqs620_pwm->chip);  in iqs620_pwm_probe()
244 		dev_err(&pdev->dev, "Failed to add device: %d\n", ret);  in iqs620_pwm_probe()
254 	ret = pwmchip_remove(&iqs620_pwm->chip);  in iqs620_pwm_remove()
256 		dev_err(&pdev->dev, "Failed to remove device: %d\n", ret);  in iqs620_pwm_remove()
263 		.name = "iqs620a-pwm",
271 MODULE_DESCRIPTION("Azoteq IQS620A PWM Generator");
273 MODULE_ALIAS("platform:iqs620a-pwm");