1/*
2 * Battery measurement code for Zipit Z2
3 *
4 * Copyright (C) 2009 Peter Edwards <sweetlilmre@gmail.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/gpio.h>
14#include <linux/i2c.h>
15#include <linux/interrupt.h>
16#include <linux/irq.h>
17#include <linux/power_supply.h>
18#include <linux/slab.h>
19#include <linux/z2_battery.h>
20
21#define	Z2_DEFAULT_NAME	"Z2"
22
23struct z2_charger {
24	struct z2_battery_info		*info;
25	int				bat_status;
26	struct i2c_client		*client;
27	struct power_supply		*batt_ps;
28	struct power_supply_desc	batt_ps_desc;
29	struct mutex			work_lock;
30	struct work_struct		bat_work;
31};
32
33static unsigned long z2_read_bat(struct z2_charger *charger)
34{
35	int data;
36	data = i2c_smbus_read_byte_data(charger->client,
37					charger->info->batt_I2C_reg);
38	if (data < 0)
39		return 0;
40
41	return data * charger->info->batt_mult / charger->info->batt_div;
42}
43
44static int z2_batt_get_property(struct power_supply *batt_ps,
45			    enum power_supply_property psp,
46			    union power_supply_propval *val)
47{
48	struct z2_charger *charger = power_supply_get_drvdata(batt_ps);
49	struct z2_battery_info *info = charger->info;
50
51	switch (psp) {
52	case POWER_SUPPLY_PROP_STATUS:
53		val->intval = charger->bat_status;
54		break;
55	case POWER_SUPPLY_PROP_TECHNOLOGY:
56		val->intval = info->batt_tech;
57		break;
58	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
59		if (info->batt_I2C_reg >= 0)
60			val->intval = z2_read_bat(charger);
61		else
62			return -EINVAL;
63		break;
64	case POWER_SUPPLY_PROP_VOLTAGE_MAX:
65		if (info->max_voltage >= 0)
66			val->intval = info->max_voltage;
67		else
68			return -EINVAL;
69		break;
70	case POWER_SUPPLY_PROP_VOLTAGE_MIN:
71		if (info->min_voltage >= 0)
72			val->intval = info->min_voltage;
73		else
74			return -EINVAL;
75		break;
76	case POWER_SUPPLY_PROP_PRESENT:
77		val->intval = 1;
78		break;
79	default:
80		return -EINVAL;
81	}
82
83	return 0;
84}
85
86static void z2_batt_ext_power_changed(struct power_supply *batt_ps)
87{
88	struct z2_charger *charger = power_supply_get_drvdata(batt_ps);
89
90	schedule_work(&charger->bat_work);
91}
92
93static void z2_batt_update(struct z2_charger *charger)
94{
95	int old_status = charger->bat_status;
96	struct z2_battery_info *info;
97
98	info = charger->info;
99
100	mutex_lock(&charger->work_lock);
101
102	charger->bat_status = (info->charge_gpio >= 0) ?
103		(gpio_get_value(info->charge_gpio) ?
104		POWER_SUPPLY_STATUS_CHARGING :
105		POWER_SUPPLY_STATUS_DISCHARGING) :
106		POWER_SUPPLY_STATUS_UNKNOWN;
107
108	if (old_status != charger->bat_status) {
109		pr_debug("%s: %i -> %i\n", charger->batt_ps->desc->name,
110				old_status,
111				charger->bat_status);
112		power_supply_changed(charger->batt_ps);
113	}
114
115	mutex_unlock(&charger->work_lock);
116}
117
118static void z2_batt_work(struct work_struct *work)
119{
120	struct z2_charger *charger;
121	charger = container_of(work, struct z2_charger, bat_work);
122	z2_batt_update(charger);
123}
124
125static irqreturn_t z2_charge_switch_irq(int irq, void *devid)
126{
127	struct z2_charger *charger = devid;
128	schedule_work(&charger->bat_work);
129	return IRQ_HANDLED;
130}
131
132static int z2_batt_ps_init(struct z2_charger *charger, int props)
133{
134	int i = 0;
135	enum power_supply_property *prop;
136	struct z2_battery_info *info = charger->info;
137
138	if (info->charge_gpio >= 0)
139		props++;	/* POWER_SUPPLY_PROP_STATUS */
140	if (info->batt_tech >= 0)
141		props++;	/* POWER_SUPPLY_PROP_TECHNOLOGY */
142	if (info->batt_I2C_reg >= 0)
143		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_NOW */
144	if (info->max_voltage >= 0)
145		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_MAX */
146	if (info->min_voltage >= 0)
147		props++;	/* POWER_SUPPLY_PROP_VOLTAGE_MIN */
148
149	prop = kzalloc(props * sizeof(*prop), GFP_KERNEL);
150	if (!prop)
151		return -ENOMEM;
152
153	prop[i++] = POWER_SUPPLY_PROP_PRESENT;
154	if (info->charge_gpio >= 0)
155		prop[i++] = POWER_SUPPLY_PROP_STATUS;
156	if (info->batt_tech >= 0)
157		prop[i++] = POWER_SUPPLY_PROP_TECHNOLOGY;
158	if (info->batt_I2C_reg >= 0)
159		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_NOW;
160	if (info->max_voltage >= 0)
161		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MAX;
162	if (info->min_voltage >= 0)
163		prop[i++] = POWER_SUPPLY_PROP_VOLTAGE_MIN;
164
165	if (!info->batt_name) {
166		dev_info(&charger->client->dev,
167				"Please consider setting proper battery "
168				"name in platform definition file, falling "
169				"back to name \" Z2_DEFAULT_NAME \"\n");
170		charger->batt_ps_desc.name = Z2_DEFAULT_NAME;
171	} else
172		charger->batt_ps_desc.name = info->batt_name;
173
174	charger->batt_ps_desc.properties	= prop;
175	charger->batt_ps_desc.num_properties	= props;
176	charger->batt_ps_desc.type		= POWER_SUPPLY_TYPE_BATTERY;
177	charger->batt_ps_desc.get_property	= z2_batt_get_property;
178	charger->batt_ps_desc.external_power_changed =
179						z2_batt_ext_power_changed;
180	charger->batt_ps_desc.use_for_apm	= 1;
181
182	return 0;
183}
184
185static int z2_batt_probe(struct i2c_client *client,
186				const struct i2c_device_id *id)
187{
188	int ret = 0;
189	int props = 1;	/* POWER_SUPPLY_PROP_PRESENT */
190	struct z2_charger *charger;
191	struct z2_battery_info *info = client->dev.platform_data;
192	struct power_supply_config psy_cfg = {};
193
194	if (info == NULL) {
195		dev_err(&client->dev,
196			"Please set platform device platform_data"
197			" to a valid z2_battery_info pointer!\n");
198		return -EINVAL;
199	}
200
201	charger = kzalloc(sizeof(*charger), GFP_KERNEL);
202	if (charger == NULL)
203		return -ENOMEM;
204
205	charger->bat_status = POWER_SUPPLY_STATUS_UNKNOWN;
206	charger->info = info;
207	charger->client = client;
208	i2c_set_clientdata(client, charger);
209	psy_cfg.drv_data = charger;
210
211	mutex_init(&charger->work_lock);
212
213	if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
214		ret = gpio_request(info->charge_gpio, "BATT CHRG");
215		if (ret)
216			goto err;
217
218		ret = gpio_direction_input(info->charge_gpio);
219		if (ret)
220			goto err2;
221
222		irq_set_irq_type(gpio_to_irq(info->charge_gpio),
223				 IRQ_TYPE_EDGE_BOTH);
224		ret = request_irq(gpio_to_irq(info->charge_gpio),
225				z2_charge_switch_irq, 0,
226				"AC Detect", charger);
227		if (ret)
228			goto err3;
229	}
230
231	ret = z2_batt_ps_init(charger, props);
232	if (ret)
233		goto err3;
234
235	INIT_WORK(&charger->bat_work, z2_batt_work);
236
237	charger->batt_ps = power_supply_register(&client->dev,
238						 &charger->batt_ps_desc,
239						 &psy_cfg);
240	if (IS_ERR(charger->batt_ps)) {
241		ret = PTR_ERR(charger->batt_ps);
242		goto err4;
243	}
244
245	schedule_work(&charger->bat_work);
246
247	return 0;
248
249err4:
250	kfree(charger->batt_ps_desc.properties);
251err3:
252	if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
253		free_irq(gpio_to_irq(info->charge_gpio), charger);
254err2:
255	if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio))
256		gpio_free(info->charge_gpio);
257err:
258	kfree(charger);
259	return ret;
260}
261
262static int z2_batt_remove(struct i2c_client *client)
263{
264	struct z2_charger *charger = i2c_get_clientdata(client);
265	struct z2_battery_info *info = charger->info;
266
267	cancel_work_sync(&charger->bat_work);
268	power_supply_unregister(charger->batt_ps);
269
270	kfree(charger->batt_ps_desc.properties);
271	if (info->charge_gpio >= 0 && gpio_is_valid(info->charge_gpio)) {
272		free_irq(gpio_to_irq(info->charge_gpio), charger);
273		gpio_free(info->charge_gpio);
274	}
275
276	kfree(charger);
277
278	return 0;
279}
280
281#ifdef CONFIG_PM
282static int z2_batt_suspend(struct device *dev)
283{
284	struct i2c_client *client = to_i2c_client(dev);
285	struct z2_charger *charger = i2c_get_clientdata(client);
286
287	flush_work(&charger->bat_work);
288	return 0;
289}
290
291static int z2_batt_resume(struct device *dev)
292{
293	struct i2c_client *client = to_i2c_client(dev);
294	struct z2_charger *charger = i2c_get_clientdata(client);
295
296	schedule_work(&charger->bat_work);
297	return 0;
298}
299
300static const struct dev_pm_ops z2_battery_pm_ops = {
301	.suspend	= z2_batt_suspend,
302	.resume		= z2_batt_resume,
303};
304
305#define	Z2_BATTERY_PM_OPS	(&z2_battery_pm_ops)
306
307#else
308#define	Z2_BATTERY_PM_OPS	(NULL)
309#endif
310
311static const struct i2c_device_id z2_batt_id[] = {
312	{ "aer915", 0 },
313	{ }
314};
315MODULE_DEVICE_TABLE(i2c, z2_batt_id);
316
317static struct i2c_driver z2_batt_driver = {
318	.driver	= {
319		.name	= "z2-battery",
320		.owner	= THIS_MODULE,
321		.pm	= Z2_BATTERY_PM_OPS
322	},
323	.probe		= z2_batt_probe,
324	.remove		= z2_batt_remove,
325	.id_table	= z2_batt_id,
326};
327module_i2c_driver(z2_batt_driver);
328
329MODULE_LICENSE("GPL");
330MODULE_AUTHOR("Peter Edwards <sweetlilmre@gmail.com>");
331MODULE_DESCRIPTION("Zipit Z2 battery driver");
332