1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2023, Nikita Travkin <nikita@trvn.ru>
4 */
5
6 #include <linux/errno.h>
7 #include <linux/module.h>
8 #include <linux/platform_device.h>
9 #include <linux/power_supply.h>
10 #include <linux/property.h>
11 #include <linux/regmap.h>
12 #include <linux/slab.h>
13 #include <linux/delay.h>
14 #include <linux/interrupt.h>
15 #include <linux/timekeeping.h>
16
17 #define PM8916_PERPH_TYPE 0x04
18 #define PM8916_BMS_VM_TYPE 0x020D
19
20 #define PM8916_SEC_ACCESS 0xD0
21 #define PM8916_SEC_MAGIC 0xA5
22
23 #define PM8916_BMS_VM_STATUS1 0x08
24 #define PM8916_BMS_VM_FSM_STATE(x) (((x) & 0b00111000) >> 3)
25 #define PM8916_BMS_VM_FSM_STATE_S2 0x2
26
27 #define PM8916_BMS_VM_MODE_CTL 0x40
28 #define PM8916_BMS_VM_MODE_FORCE_S3 (BIT(0) | BIT(1))
29 #define PM8916_BMS_VM_MODE_NORMAL (BIT(1) | BIT(3))
30
31 #define PM8916_BMS_VM_EN_CTL 0x46
32 #define PM8916_BMS_ENABLED BIT(7)
33
34 #define PM8916_BMS_VM_FIFO_LENGTH_CTL 0x47
35 #define PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL 0x55
36 #define PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL 0x56
37 #define PM8916_BMS_VM_S3_S7_OCV_DATA0 0x6A
38 #define PM8916_BMS_VM_BMS_FIFO_REG_0_LSB 0xC0
39
40 /* Using only 1 fifo is broken in hardware */
41 #define PM8916_BMS_VM_FIFO_COUNT 2 /* 2 .. 8 */
42
43 #define PM8916_BMS_VM_S1_SAMPLE_INTERVAL 10
44 #define PM8916_BMS_VM_S2_SAMPLE_INTERVAL 10
45
46 struct pm8916_bms_vm_battery {
47 struct device *dev;
48 struct power_supply *battery;
49 struct power_supply_battery_info *info;
50 struct regmap *regmap;
51 unsigned int reg;
52 unsigned int last_ocv;
53 time64_t last_ocv_time;
54 unsigned int vbat_now;
55 };
56
pm8916_bms_vm_battery_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)57 static int pm8916_bms_vm_battery_get_property(struct power_supply *psy,
58 enum power_supply_property psp,
59 union power_supply_propval *val)
60 {
61 struct pm8916_bms_vm_battery *bat = power_supply_get_drvdata(psy);
62 struct power_supply_battery_info *info = bat->info;
63 int supplied;
64
65 switch (psp) {
66 case POWER_SUPPLY_PROP_STATUS:
67 supplied = power_supply_am_i_supplied(psy);
68
69 if (supplied < 0 && supplied != -ENODEV)
70 return supplied;
71 else if (supplied && supplied != -ENODEV)
72 val->intval = POWER_SUPPLY_STATUS_CHARGING;
73 else
74 val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
75 return 0;
76
77 case POWER_SUPPLY_PROP_HEALTH:
78 if (bat->vbat_now < info->voltage_min_design_uv)
79 val->intval = POWER_SUPPLY_HEALTH_DEAD;
80 else if (bat->vbat_now > info->voltage_max_design_uv)
81 val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
82 else
83 val->intval = POWER_SUPPLY_HEALTH_GOOD;
84 return 0;
85
86 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
87 val->intval = bat->vbat_now;
88 return 0;
89
90 case POWER_SUPPLY_PROP_VOLTAGE_OCV:
91 /*
92 * Hardware only reliably measures OCV when the system is off or suspended.
93 * We expose the last known OCV value on boot, invalidating it after 180 seconds.
94 */
95 if (ktime_get_seconds() - bat->last_ocv_time > 180)
96 return -ENODATA;
97
98 val->intval = bat->last_ocv;
99 return 0;
100
101 default:
102 return -EINVAL;
103 }
104 }
105
106 static enum power_supply_property pm8916_bms_vm_battery_properties[] = {
107 POWER_SUPPLY_PROP_STATUS,
108 POWER_SUPPLY_PROP_VOLTAGE_NOW,
109 POWER_SUPPLY_PROP_VOLTAGE_OCV,
110 POWER_SUPPLY_PROP_HEALTH,
111 };
112
pm8916_bms_vm_fifo_update_done_irq(int irq,void * data)113 static irqreturn_t pm8916_bms_vm_fifo_update_done_irq(int irq, void *data)
114 {
115 struct pm8916_bms_vm_battery *bat = data;
116 u16 vbat_data[PM8916_BMS_VM_FIFO_COUNT];
117 int ret;
118
119 ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_BMS_VM_BMS_FIFO_REG_0_LSB,
120 &vbat_data, PM8916_BMS_VM_FIFO_COUNT * 2);
121 if (ret)
122 return IRQ_HANDLED;
123
124 /*
125 * The VM-BMS hardware only collects voltage data and the software
126 * has to process it to calculate the OCV and SoC. Hardware provides
127 * up to 8 averaged measurements for software to take in account.
128 *
129 * Just use the last measured value for now to report the current
130 * battery voltage.
131 */
132 bat->vbat_now = vbat_data[PM8916_BMS_VM_FIFO_COUNT - 1] * 300;
133
134 power_supply_changed(bat->battery);
135
136 return IRQ_HANDLED;
137 }
138
139 static const struct power_supply_desc pm8916_bms_vm_battery_psy_desc = {
140 .name = "pm8916-bms-vm",
141 .type = POWER_SUPPLY_TYPE_BATTERY,
142 .properties = pm8916_bms_vm_battery_properties,
143 .num_properties = ARRAY_SIZE(pm8916_bms_vm_battery_properties),
144 .get_property = pm8916_bms_vm_battery_get_property,
145 };
146
pm8916_bms_vm_battery_probe(struct platform_device * pdev)147 static int pm8916_bms_vm_battery_probe(struct platform_device *pdev)
148 {
149 struct device *dev = &pdev->dev;
150 struct pm8916_bms_vm_battery *bat;
151 struct power_supply_config psy_cfg = {};
152 int ret, irq;
153 unsigned int tmp;
154
155 bat = devm_kzalloc(dev, sizeof(*bat), GFP_KERNEL);
156 if (!bat)
157 return -ENOMEM;
158
159 bat->dev = dev;
160
161 bat->regmap = dev_get_regmap(pdev->dev.parent, NULL);
162 if (!bat->regmap)
163 return -ENODEV;
164
165 ret = device_property_read_u32(dev, "reg", &bat->reg);
166 if (ret < 0)
167 return -EINVAL;
168
169 ret = regmap_bulk_read(bat->regmap, bat->reg + PM8916_PERPH_TYPE, &tmp, 2);
170 if (ret)
171 goto comm_error;
172
173 if (tmp != PM8916_BMS_VM_TYPE)
174 return dev_err_probe(dev, -ENODEV, "Device reported wrong type: 0x%X\n", tmp);
175
176 ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S1_SAMPLE_INTERVAL_CTL,
177 PM8916_BMS_VM_S1_SAMPLE_INTERVAL);
178 if (ret)
179 goto comm_error;
180 ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_S2_SAMPLE_INTERVAL_CTL,
181 PM8916_BMS_VM_S2_SAMPLE_INTERVAL);
182 if (ret)
183 goto comm_error;
184 ret = regmap_write(bat->regmap, bat->reg + PM8916_BMS_VM_FIFO_LENGTH_CTL,
185 PM8916_BMS_VM_FIFO_COUNT << 4 | PM8916_BMS_VM_FIFO_COUNT);
186 if (ret)
187 goto comm_error;
188 ret = regmap_write(bat->regmap,
189 bat->reg + PM8916_BMS_VM_EN_CTL, PM8916_BMS_ENABLED);
190 if (ret)
191 goto comm_error;
192
193 ret = regmap_bulk_read(bat->regmap,
194 bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
195 if (ret)
196 goto comm_error;
197
198 bat->last_ocv_time = ktime_get_seconds();
199 bat->last_ocv = tmp * 300;
200 bat->vbat_now = bat->last_ocv;
201
202 psy_cfg.drv_data = bat;
203 psy_cfg.fwnode = dev_fwnode(dev);
204
205 bat->battery = devm_power_supply_register(dev, &pm8916_bms_vm_battery_psy_desc, &psy_cfg);
206 if (IS_ERR(bat->battery))
207 return dev_err_probe(dev, PTR_ERR(bat->battery), "Unable to register battery\n");
208
209 ret = power_supply_get_battery_info(bat->battery, &bat->info);
210 if (ret)
211 return dev_err_probe(dev, ret, "Unable to get battery info\n");
212
213 irq = platform_get_irq_byname(pdev, "fifo");
214 if (irq < 0)
215 return irq;
216
217 ret = devm_request_threaded_irq(dev, irq, NULL, pm8916_bms_vm_fifo_update_done_irq,
218 IRQF_ONESHOT, "pm8916_vm_bms", bat);
219 if (ret)
220 return ret;
221
222 platform_set_drvdata(pdev, bat);
223
224 return 0;
225
226 comm_error:
227 return dev_err_probe(dev, ret, "Unable to communicate with device\n");
228 }
229
pm8916_bms_vm_battery_suspend(struct platform_device * pdev,pm_message_t state)230 static int pm8916_bms_vm_battery_suspend(struct platform_device *pdev, pm_message_t state)
231 {
232 struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
233 int ret;
234
235 /*
236 * Due to a hardware quirk the FSM doesn't switch states normally.
237 * Instead we unlock the debug registers and force S3 (Measure OCV/Sleep)
238 * mode every time we suspend.
239 */
240
241 ret = regmap_write(bat->regmap,
242 bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
243 if (ret)
244 goto error;
245 ret = regmap_write(bat->regmap,
246 bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_FORCE_S3);
247 if (ret)
248 goto error;
249
250 return 0;
251
252 error:
253 dev_err(bat->dev, "Failed to force S3 mode: %pe\n", ERR_PTR(ret));
254 return ret;
255 }
256
pm8916_bms_vm_battery_resume(struct platform_device * pdev)257 static int pm8916_bms_vm_battery_resume(struct platform_device *pdev)
258 {
259 struct pm8916_bms_vm_battery *bat = platform_get_drvdata(pdev);
260 int ret;
261 unsigned int tmp;
262
263 ret = regmap_bulk_read(bat->regmap,
264 bat->reg + PM8916_BMS_VM_S3_S7_OCV_DATA0, &tmp, 2);
265
266 bat->last_ocv_time = ktime_get_seconds();
267 bat->last_ocv = tmp * 300;
268
269 ret = regmap_write(bat->regmap,
270 bat->reg + PM8916_SEC_ACCESS, PM8916_SEC_MAGIC);
271 if (ret)
272 goto error;
273 ret = regmap_write(bat->regmap,
274 bat->reg + PM8916_BMS_VM_MODE_CTL, PM8916_BMS_VM_MODE_NORMAL);
275 if (ret)
276 goto error;
277
278 return 0;
279
280 error:
281 dev_err(bat->dev, "Failed to return normal mode: %pe\n", ERR_PTR(ret));
282 return ret;
283 }
284
285 static const struct of_device_id pm8916_bms_vm_battery_of_match[] = {
286 { .compatible = "qcom,pm8916-bms-vm", },
287 {}
288 };
289 MODULE_DEVICE_TABLE(of, pm8916_bms_vm_battery_of_match);
290
291 static struct platform_driver pm8916_bms_vm_battery_driver = {
292 .driver = {
293 .name = "pm8916-bms-vm",
294 .of_match_table = pm8916_bms_vm_battery_of_match,
295 },
296 .probe = pm8916_bms_vm_battery_probe,
297 .suspend = pm8916_bms_vm_battery_suspend,
298 .resume = pm8916_bms_vm_battery_resume,
299 };
300 module_platform_driver(pm8916_bms_vm_battery_driver);
301
302 MODULE_DESCRIPTION("pm8916 BMS-VM driver");
303 MODULE_AUTHOR("Nikita Travkin <nikita@trvn.ru>");
304 MODULE_LICENSE("GPL");
305