1 // SPDX-License-Identifier: GPL-2.0
3  * Expose a PWM controlled by the ChromeOS EC to the host processor.
12 #include <linux/pwm.h>
16  * struct cros_ec_pwm_device - Driver data for EC PWM
19  * @ec: Pointer to EC device
20  * @chip: PWM controller chip
24 	struct cros_ec_device *ec;  member
33 static int cros_ec_pwm_set_duty(struct cros_ec_device *ec, u8 index, u16 duty)  in cros_ec_pwm_set_duty()  argument
44 	msg->version = 0;  in cros_ec_pwm_set_duty()
45 	msg->command = EC_CMD_PWM_SET_DUTY;  in cros_ec_pwm_set_duty()
46 	msg->insize = 0;  in cros_ec_pwm_set_duty()
47 	msg->outsize = sizeof(*params);  in cros_ec_pwm_set_duty()
49 	params->duty = duty;  in cros_ec_pwm_set_duty()
50 	params->pwm_type = EC_PWM_TYPE_GENERIC;  in cros_ec_pwm_set_duty()
51 	params->index = index;  in cros_ec_pwm_set_duty()
53 	return cros_ec_cmd_xfer_status(ec, msg);  in cros_ec_pwm_set_duty()
56 static int __cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index,  in __cros_ec_pwm_get_duty()  argument
73 	msg->version = 0;  in __cros_ec_pwm_get_duty()
74 	msg->command = EC_CMD_PWM_GET_DUTY;  in __cros_ec_pwm_get_duty()
75 	msg->insize = sizeof(*resp);  in __cros_ec_pwm_get_duty()
76 	msg->outsize = sizeof(*params);  in __cros_ec_pwm_get_duty()
78 	params->pwm_type = EC_PWM_TYPE_GENERIC;  in __cros_ec_pwm_get_duty()
79 	params->index = index;  in __cros_ec_pwm_get_duty()
81 	ret = cros_ec_cmd_xfer_status(ec, msg);  in __cros_ec_pwm_get_duty()
83 		*result = msg->result;  in __cros_ec_pwm_get_duty()
87 	return resp->duty;  in __cros_ec_pwm_get_duty()
90 static int cros_ec_pwm_get_duty(struct cros_ec_device *ec, u8 index)  in cros_ec_pwm_get_duty()  argument
92 	return __cros_ec_pwm_get_duty(ec, index, NULL);  in cros_ec_pwm_get_duty()
95 static int cros_ec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,  in cros_ec_pwm_apply()  argument
101 	/* The EC won't let us change the period */  in cros_ec_pwm_apply()
102 	if (state->period != EC_PWM_MAX_DUTY)  in cros_ec_pwm_apply()
103 		return -EINVAL;  in cros_ec_pwm_apply()
106 	 * EC doesn't separate the concept of duty cycle and enabled, but  in cros_ec_pwm_apply()
109 	duty_cycle = state->enabled ? state->duty_cycle : 0;  in cros_ec_pwm_apply()
111 	return cros_ec_pwm_set_duty(ec_pwm->ec, pwm->hwpwm, duty_cycle);  in cros_ec_pwm_apply()
114 static void cros_ec_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,  in cros_ec_pwm_get_state()  argument
120 	ret = cros_ec_pwm_get_duty(ec_pwm->ec, pwm->hwpwm);  in cros_ec_pwm_get_state()
122 		dev_err(chip->dev, "error getting initial duty: %d\n", ret);  in cros_ec_pwm_get_state()
126 	state->enabled = (ret > 0);  in cros_ec_pwm_get_state()
127 	state->period = EC_PWM_MAX_DUTY;  in cros_ec_pwm_get_state()
130 	state->duty_cycle = ret;  in cros_ec_pwm_get_state()
136 	struct pwm_device *pwm;  in cros_ec_pwm_xlate()  local
138 	if (args->args[0] >= pc->npwm)  in cros_ec_pwm_xlate()
139 		return ERR_PTR(-EINVAL);  in cros_ec_pwm_xlate()
141 	pwm = pwm_request_from_chip(pc, args->args[0], NULL);  in cros_ec_pwm_xlate()
142 	if (IS_ERR(pwm))  in cros_ec_pwm_xlate()
143 		return pwm;  in cros_ec_pwm_xlate()
145 	/* The EC won't let us change the period */  in cros_ec_pwm_xlate()
146 	pwm->args.period = EC_PWM_MAX_DUTY;  in cros_ec_pwm_xlate()
148 	return pwm;  in cros_ec_pwm_xlate()
157 static int cros_ec_num_pwms(struct cros_ec_device *ec)  in cros_ec_num_pwms()  argument
165 		ret = __cros_ec_pwm_get_duty(ec, i, &result);  in cros_ec_num_pwms()
166 		/* We want to parse EC protocol errors */  in cros_ec_num_pwms()
167 		if (ret < 0 && !(ret == -EPROTO && result))  in cros_ec_num_pwms()
175 			return -ENODEV;  in cros_ec_num_pwms()
179 			return -EPROTO;  in cros_ec_num_pwms()
187 	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);  in cros_ec_pwm_probe()  local
188 	struct device *dev = &pdev->dev;  in cros_ec_pwm_probe()
193 	if (!ec) {  in cros_ec_pwm_probe()
194 		dev_err(dev, "no parent EC device\n");  in cros_ec_pwm_probe()
195 		return -EINVAL;  in cros_ec_pwm_probe()
200 		return -ENOMEM;  in cros_ec_pwm_probe()
201 	chip = &ec_pwm->chip;  in cros_ec_pwm_probe()
202 	ec_pwm->ec = ec;  in cros_ec_pwm_probe()
204 	/* PWM chip */  in cros_ec_pwm_probe()
205 	chip->dev = dev;  in cros_ec_pwm_probe()
206 	chip->ops = &cros_ec_pwm_ops;  in cros_ec_pwm_probe()
207 	chip->of_xlate = cros_ec_pwm_xlate;  in cros_ec_pwm_probe()
208 	chip->of_pwm_n_cells = 1;  in cros_ec_pwm_probe()
209 	chip->base = -1;  in cros_ec_pwm_probe()
210 	ret = cros_ec_num_pwms(ec);  in cros_ec_pwm_probe()
215 	chip->npwm = ret;  in cros_ec_pwm_probe()
216 	dev_dbg(dev, "Probed %u PWMs\n", chip->npwm);  in cros_ec_pwm_probe()
220 		dev_err(dev, "cannot register PWM: %d\n", ret);  in cros_ec_pwm_probe()
232 	struct pwm_chip *chip = &ec_pwm->chip;  in cros_ec_pwm_remove()
239 	{ .compatible = "google,cros-ec-pwm" },
249 		.name = "cros-ec-pwm",
255 MODULE_ALIAS("platform:cros-ec-pwm");
256 MODULE_DESCRIPTION("ChromeOS EC PWM driver");