1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Battery driver for the Ingenic JZ47xx SoCs
4 * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
5 *
6 * based on drivers/power/supply/jz4740-battery.c
7 */
8
9 #include <linux/iio/consumer.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/power_supply.h>
14 #include <linux/property.h>
15
16 struct ingenic_battery {
17 struct device *dev;
18 struct iio_channel *channel;
19 struct power_supply_desc desc;
20 struct power_supply *battery;
21 struct power_supply_battery_info *info;
22 };
23
ingenic_battery_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)24 static int ingenic_battery_get_property(struct power_supply *psy,
25 enum power_supply_property psp,
26 union power_supply_propval *val)
27 {
28 struct ingenic_battery *bat = power_supply_get_drvdata(psy);
29 struct power_supply_battery_info *info = bat->info;
30 int ret;
31
32 switch (psp) {
33 case POWER_SUPPLY_PROP_HEALTH:
34 ret = iio_read_channel_processed_scale(bat->channel,
35 &val->intval,
36 1000);
37 if (val->intval < info->voltage_min_design_uv)
38 val->intval = POWER_SUPPLY_HEALTH_DEAD;
39 else if (val->intval > info->voltage_max_design_uv)
40 val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
41 else
42 val->intval = POWER_SUPPLY_HEALTH_GOOD;
43 return ret;
44 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
45 ret = iio_read_channel_processed_scale(bat->channel,
46 &val->intval,
47 1000);
48 return ret;
49 case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
50 val->intval = info->voltage_min_design_uv;
51 return 0;
52 case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
53 val->intval = info->voltage_max_design_uv;
54 return 0;
55 default:
56 return -EINVAL;
57 }
58 }
59
60 /* Set the most appropriate IIO channel voltage reference scale
61 * based on the battery's max voltage.
62 */
ingenic_battery_set_scale(struct ingenic_battery * bat)63 static int ingenic_battery_set_scale(struct ingenic_battery *bat)
64 {
65 const int *scale_raw;
66 int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret;
67 u64 max_mV;
68
69 ret = iio_read_max_channel_raw(bat->channel, &max_raw);
70 if (ret) {
71 dev_err(bat->dev, "Unable to read max raw channel value\n");
72 return ret;
73 }
74
75 ret = iio_read_avail_channel_attribute(bat->channel, &scale_raw,
76 &scale_type, &scale_len,
77 IIO_CHAN_INFO_SCALE);
78 if (ret < 0) {
79 dev_err(bat->dev, "Unable to read channel avail scale\n");
80 return ret;
81 }
82 if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2)
83 return -EINVAL;
84
85 max_mV = bat->info->voltage_max_design_uv / 1000;
86
87 for (i = 0; i < scale_len; i += 2) {
88 u64 scale_mV = (max_raw * scale_raw[i]) >> scale_raw[i + 1];
89
90 if (scale_mV < max_mV)
91 continue;
92
93 if (best_idx >= 0 && scale_mV > best_mV)
94 continue;
95
96 best_mV = scale_mV;
97 best_idx = i;
98 }
99
100 if (best_idx < 0) {
101 dev_err(bat->dev, "Unable to find matching voltage scale\n");
102 return -EINVAL;
103 }
104
105 /* Only set scale if there is more than one (fractional) entry */
106 if (scale_len > 2) {
107 ret = iio_write_channel_attribute(bat->channel,
108 scale_raw[best_idx],
109 scale_raw[best_idx + 1],
110 IIO_CHAN_INFO_SCALE);
111 if (ret)
112 return ret;
113 }
114
115 return 0;
116 }
117
118 static enum power_supply_property ingenic_battery_properties[] = {
119 POWER_SUPPLY_PROP_HEALTH,
120 POWER_SUPPLY_PROP_VOLTAGE_NOW,
121 POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
122 POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
123 };
124
ingenic_battery_probe(struct platform_device * pdev)125 static int ingenic_battery_probe(struct platform_device *pdev)
126 {
127 struct device *dev = &pdev->dev;
128 struct ingenic_battery *bat;
129 struct power_supply_config psy_cfg = {};
130 struct power_supply_desc *desc;
131 int ret;
132
133 bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);
134 if (!bat)
135 return -ENOMEM;
136
137 bat->dev = dev;
138 bat->channel = devm_iio_channel_get(dev, "battery");
139 if (IS_ERR(bat->channel))
140 return PTR_ERR(bat->channel);
141
142 desc = &bat->desc;
143 desc->name = "jz-battery";
144 desc->type = POWER_SUPPLY_TYPE_BATTERY;
145 desc->properties = ingenic_battery_properties;
146 desc->num_properties = ARRAY_SIZE(ingenic_battery_properties);
147 desc->get_property = ingenic_battery_get_property;
148 psy_cfg.drv_data = bat;
149 psy_cfg.of_node = dev->of_node;
150
151 bat->battery = devm_power_supply_register(dev, desc, &psy_cfg);
152 if (IS_ERR(bat->battery))
153 return dev_err_probe(dev, PTR_ERR(bat->battery),
154 "Unable to register battery\n");
155
156 ret = power_supply_get_battery_info(bat->battery, &bat->info);
157 if (ret) {
158 dev_err(dev, "Unable to get battery info: %d\n", ret);
159 return ret;
160 }
161 if (bat->info->voltage_min_design_uv < 0) {
162 dev_err(dev, "Unable to get voltage min design\n");
163 return bat->info->voltage_min_design_uv;
164 }
165 if (bat->info->voltage_max_design_uv < 0) {
166 dev_err(dev, "Unable to get voltage max design\n");
167 return bat->info->voltage_max_design_uv;
168 }
169
170 return ingenic_battery_set_scale(bat);
171 }
172
173 #ifdef CONFIG_OF
174 static const struct of_device_id ingenic_battery_of_match[] = {
175 { .compatible = "ingenic,jz4740-battery", },
176 { },
177 };
178 MODULE_DEVICE_TABLE(of, ingenic_battery_of_match);
179 #endif
180
181 static struct platform_driver ingenic_battery_driver = {
182 .driver = {
183 .name = "ingenic-battery",
184 .of_match_table = of_match_ptr(ingenic_battery_of_match),
185 },
186 .probe = ingenic_battery_probe,
187 };
188 module_platform_driver(ingenic_battery_driver);
189
190 MODULE_DESCRIPTION("Battery driver for Ingenic JZ47xx SoCs");
191 MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>");
192 MODULE_LICENSE("GPL");
193