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