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_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 */ 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 }; 124 125 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