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 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 */ 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 return iio_write_channel_attribute(bat->channel, 104 scale_raw[best_idx], 105 scale_raw[best_idx + 1], 106 IIO_CHAN_INFO_SCALE); 107 } 108 109 static enum power_supply_property ingenic_battery_properties[] = { 110 POWER_SUPPLY_PROP_HEALTH, 111 POWER_SUPPLY_PROP_VOLTAGE_NOW, 112 POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN, 113 POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN, 114 }; 115 116 static int ingenic_battery_probe(struct platform_device *pdev) 117 { 118 struct device *dev = &pdev->dev; 119 struct ingenic_battery *bat; 120 struct power_supply_config psy_cfg = {}; 121 struct power_supply_desc *desc; 122 int ret; 123 124 bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL); 125 if (!bat) 126 return -ENOMEM; 127 128 bat->dev = dev; 129 bat->channel = devm_iio_channel_get(dev, "battery"); 130 if (IS_ERR(bat->channel)) 131 return PTR_ERR(bat->channel); 132 133 desc = &bat->desc; 134 desc->name = "jz-battery"; 135 desc->type = POWER_SUPPLY_TYPE_BATTERY; 136 desc->properties = ingenic_battery_properties; 137 desc->num_properties = ARRAY_SIZE(ingenic_battery_properties); 138 desc->get_property = ingenic_battery_get_property; 139 psy_cfg.drv_data = bat; 140 psy_cfg.of_node = dev->of_node; 141 142 bat->battery = devm_power_supply_register(dev, desc, &psy_cfg); 143 if (IS_ERR(bat->battery)) { 144 dev_err(dev, "Unable to register battery\n"); 145 return PTR_ERR(bat->battery); 146 } 147 148 ret = power_supply_get_battery_info(bat->battery, &bat->info); 149 if (ret) { 150 dev_err(dev, "Unable to get battery info: %d\n", ret); 151 return ret; 152 } 153 if (bat->info.voltage_min_design_uv < 0) { 154 dev_err(dev, "Unable to get voltage min design\n"); 155 return bat->info.voltage_min_design_uv; 156 } 157 if (bat->info.voltage_max_design_uv < 0) { 158 dev_err(dev, "Unable to get voltage max design\n"); 159 return bat->info.voltage_max_design_uv; 160 } 161 162 return ingenic_battery_set_scale(bat); 163 } 164 165 #ifdef CONFIG_OF 166 static const struct of_device_id ingenic_battery_of_match[] = { 167 { .compatible = "ingenic,jz4740-battery", }, 168 { }, 169 }; 170 MODULE_DEVICE_TABLE(of, ingenic_battery_of_match); 171 #endif 172 173 static struct platform_driver ingenic_battery_driver = { 174 .driver = { 175 .name = "ingenic-battery", 176 .of_match_table = of_match_ptr(ingenic_battery_of_match), 177 }, 178 .probe = ingenic_battery_probe, 179 }; 180 module_platform_driver(ingenic_battery_driver); 181 182 MODULE_DESCRIPTION("Battery driver for Ingenic JZ47xx SoCs"); 183 MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>"); 184 MODULE_LICENSE("GPL"); 185