1 /*
2  * Copyright (C) 2016 Rockchip Electronics Co., Ltd
3  *
4  * Based on kernel drivers/regulator/pwm-regulator.c
5  * Copyright (C) 2014 - STMicroelectronics Inc.
6  * Author: Lee Jones <lee.jones@linaro.org>
7  *
8  * SPDX-License-Identifier:	GPL-2.0+
9  */
10 
11 #include <common.h>
12 #include <dm.h>
13 #include <errno.h>
14 #include <pwm.h>
15 #include <power/regulator.h>
16 #include <libfdt.h>
17 #include <fdt_support.h>
18 #include <fdtdec.h>
19 
20 DECLARE_GLOBAL_DATA_PTR;
21 
22 struct pwm_regulator_info {
23 	/* pwm id corresponding to the PWM driver */
24 	int pwm_id;
25 	/* the period of one PWM cycle */
26 	int period_ns;
27 	struct udevice *pwm;
28 	/* initialize voltage of regulator */
29 	unsigned int init_voltage;
30 	/* the maximum voltage of regulator */
31 	unsigned int max_voltage;
32 	/* the minimum voltage of regulator */
33 	unsigned int min_voltage;
34 	/* the current voltage of regulator */
35 	unsigned int volt_uV;
36 };
37 
38 static int pwm_regulator_enable(struct udevice *dev, bool enable)
39 {
40 	struct pwm_regulator_info *priv = dev_get_priv(dev);
41 
42 	return pwm_set_enable(priv->pwm, priv->pwm_id, enable);
43 }
44 
45 static int pwm_voltage_to_duty_cycle_percentage(struct udevice *dev, int req_uV)
46 {
47 	struct pwm_regulator_info *priv = dev_get_priv(dev);
48 	int min_uV = priv->min_voltage;
49 	int max_uV = priv->max_voltage;
50 	int diff = max_uV - min_uV;
51 
52 	return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
53 }
54 
55 static int pwm_regulator_get_voltage(struct udevice *dev)
56 {
57 	struct pwm_regulator_info *priv = dev_get_priv(dev);
58 
59 	return priv->volt_uV;
60 }
61 
62 static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)
63 {
64 	struct pwm_regulator_info *priv = dev_get_priv(dev);
65 	int duty_cycle;
66 	int ret = 0;
67 
68 	duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);
69 
70 	ret = pwm_set_config(priv->pwm, priv->pwm_id,
71 			(priv->period_ns / 100) * duty_cycle, priv->period_ns);
72 	if (ret) {
73 		dev_err(dev, "Failed to configure PWM\n");
74 		return ret;
75 	}
76 
77 	ret = pwm_set_enable(priv->pwm, priv->pwm_id, true);
78 	if (ret) {
79 		dev_err(dev, "Failed to enable PWM\n");
80 		return ret;
81 	}
82 	priv->volt_uV = uvolt;
83 	return ret;
84 }
85 
86 static int pwm_regulator_ofdata_to_platdata(struct udevice *dev)
87 {
88 	struct pwm_regulator_info *priv = dev_get_priv(dev);
89 	struct fdtdec_phandle_args args;
90 	const void *blob = gd->fdt_blob;
91 	int node = dev_of_offset(dev);
92 	int ret;
93 
94 	ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells",
95 					     0, 0, &args);
96 	if (ret) {
97 		debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
98 		return ret;
99 	}
100 	/* TODO: pwm_id here from device tree if needed */
101 
102 	priv->period_ns = args.args[1];
103 
104 	priv->init_voltage = fdtdec_get_int(blob, node,
105 			"regulator-init-microvolt", -1);
106 	if (priv->init_voltage < 0) {
107 		printf("Cannot find regulator pwm init_voltage\n");
108 		return -EINVAL;
109 	}
110 
111 	ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm);
112 	if (ret) {
113 		debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
114 		return ret;
115 	}
116 
117 	return 0;
118 }
119 
120 static int pwm_regulator_probe(struct udevice *dev)
121 {
122 	struct pwm_regulator_info *priv = dev_get_priv(dev);
123 	struct dm_regulator_uclass_platdata *uc_pdata;
124 
125 	uc_pdata = dev_get_uclass_platdata(dev);
126 
127 	uc_pdata->type = REGULATOR_TYPE_BUCK;
128 	uc_pdata->mode_count = 0;
129 	priv->max_voltage = uc_pdata->max_uV;
130 	priv->min_voltage = uc_pdata->min_uV;
131 
132 	if (priv->init_voltage)
133 		pwm_regulator_set_voltage(dev, priv->init_voltage);
134 
135 	pwm_regulator_enable(dev, 1);
136 
137 	return 0;
138 }
139 
140 static const struct dm_regulator_ops pwm_regulator_ops = {
141 	.get_value  = pwm_regulator_get_voltage,
142 	.set_value  = pwm_regulator_set_voltage,
143 	.set_enable = pwm_regulator_enable,
144 };
145 
146 static const struct udevice_id pwm_regulator_ids[] = {
147 	{ .compatible = "pwm-regulator" },
148 	{ }
149 };
150 
151 U_BOOT_DRIVER(pwm_regulator) = {
152 	.name = "pwm_regulator",
153 	.id = UCLASS_REGULATOR,
154 	.ops = &pwm_regulator_ops,
155 	.probe = pwm_regulator_probe,
156 	.of_match = pwm_regulator_ids,
157 	.ofdata_to_platdata	= pwm_regulator_ofdata_to_platdata,
158 	.priv_auto_alloc_size	= sizeof(struct pwm_regulator_info),
159 };
160