1/*
  2 * Battery charger driver for the Maxim 14577
  3 *
  4 * Copyright (C) 2013 Samsung Electronics
  5 * Krzysztof Kozlowski <k.kozlowski@samsung.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License as published by
  9 * the Free Software Foundation; either version 2 of the License, or
 10 * (at your option) any later version.
 11 *
 12 * This program is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15 * GNU General Public License for more details.
 16 */
 17
 18#include <linux/module.h>
 19#include <linux/platform_device.h>
 20#include <linux/power_supply.h>
 21#include <linux/mfd/max14577-private.h>
 22
 23struct max14577_charger {
 24	struct device *dev;
 25	struct max14577	*max14577;
 26	struct power_supply	charger;
 27
 28	unsigned int	charging_state;
 29	unsigned int	battery_state;
 30};
 31
 32static int max14577_get_charger_state(struct max14577_charger *chg)
 33{
 34	struct regmap *rmap = chg->max14577->regmap;
 35	int state = POWER_SUPPLY_STATUS_DISCHARGING;
 36	u8 reg_data;
 37
 38	/*
 39	 * Charging occurs only if:
 40	 *  - CHGCTRL2/MBCHOSTEN == 1
 41	 *  - STATUS2/CGMBC == 1
 42	 *
 43	 * TODO:
 44	 *  - handle FULL after Top-off timer (EOC register may be off
 45	 *    and the charger won't be charging although MBCHOSTEN is on)
 46	 *  - handle properly dead-battery charging (respect timer)
 47	 *  - handle timers (fast-charge and prequal) /MBCCHGERR/
 48	 */
 49	max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
 50	if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0)
 51		goto state_set;
 52
 53	max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
 54	if (reg_data & STATUS3_CGMBC_MASK) {
 55		/* Charger or USB-cable is connected */
 56		if (reg_data & STATUS3_EOC_MASK)
 57			state = POWER_SUPPLY_STATUS_FULL;
 58		else
 59			state = POWER_SUPPLY_STATUS_CHARGING;
 60		goto state_set;
 61	}
 62
 63state_set:
 64	chg->charging_state = state;
 65	return state;
 66}
 67
 68/*
 69 * Supported charge types:
 70 *  - POWER_SUPPLY_CHARGE_TYPE_NONE
 71 *  - POWER_SUPPLY_CHARGE_TYPE_FAST
 72 */
 73static int max14577_get_charge_type(struct max14577_charger *chg)
 74{
 75	/*
 76	 * TODO: CHARGE_TYPE_TRICKLE (VCHGR_RC or EOC)?
 77	 * As spec says:
 78	 * [after reaching EOC interrupt]
 79	 * "When the battery is fully charged, the 30-minute (typ)
 80	 *  top-off timer starts. The device continues to trickle
 81	 *  charge the battery until the top-off timer runs out."
 82	 */
 83	if (max14577_get_charger_state(chg) == POWER_SUPPLY_STATUS_CHARGING)
 84		return POWER_SUPPLY_CHARGE_TYPE_FAST;
 85	return POWER_SUPPLY_CHARGE_TYPE_NONE;
 86}
 87
 88static int max14577_get_online(struct max14577_charger *chg)
 89{
 90	struct regmap *rmap = chg->max14577->regmap;
 91	u8 reg_data;
 92
 93	max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
 94	reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
 95	switch (reg_data) {
 96	case MAX14577_CHARGER_TYPE_USB:
 97	case MAX14577_CHARGER_TYPE_DEDICATED_CHG:
 98	case MAX14577_CHARGER_TYPE_SPECIAL_500MA:
 99	case MAX14577_CHARGER_TYPE_SPECIAL_1A:
100	case MAX14577_CHARGER_TYPE_DEAD_BATTERY:
101		return 1;
102	case MAX14577_CHARGER_TYPE_NONE:
103	case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT:
104	case MAX14577_CHARGER_TYPE_RESERVED:
105	default:
106		return 0;
107	}
108}
109
110/*
111 * Supported health statuses:
112 *  - POWER_SUPPLY_HEALTH_DEAD
113 *  - POWER_SUPPLY_HEALTH_OVERVOLTAGE
114 *  - POWER_SUPPLY_HEALTH_GOOD
115 */
116static int max14577_get_battery_health(struct max14577_charger *chg)
117{
118	struct regmap *rmap = chg->max14577->regmap;
119	int state = POWER_SUPPLY_HEALTH_GOOD;
120	u8 reg_data;
121
122	max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, &reg_data);
123	reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT);
124	if (reg_data == MAX14577_CHARGER_TYPE_DEAD_BATTERY) {
125		state = POWER_SUPPLY_HEALTH_DEAD;
126		goto state_set;
127	}
128
129	max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
130	if (reg_data & STATUS3_OVP_MASK) {
131		state = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
132		goto state_set;
133	}
134
135state_set:
136	chg->battery_state = state;
137	return state;
138}
139
140/*
141 * Always returns 1.
142 * The max14577 chip doesn't report any status of battery presence.
143 * Lets assume that it will always be used with some battery.
144 */
145static int max14577_get_present(struct max14577_charger *chg)
146{
147	return 1;
148}
149
150/*
151 * Sets charger registers to proper and safe default values.
152 * Some of these values are equal to defaults in MAX14577E
153 * data sheet but there are minor differences.
154 */
155static void max14577_charger_reg_init(struct max14577_charger *chg)
156{
157	struct regmap *rmap = chg->max14577->regmap;
158	u8 reg_data;
159
160	/*
161	 * Charger-Type Manual Detection, default off (set CHGTYPMAN to 0)
162	 * Charger-Detection Enable, default on (set CHGDETEN to 1)
163	 * Combined mask of CHGDETEN and CHGTYPMAN will zero the CHGTYPMAN bit
164	 */
165	reg_data = 0x1 << CDETCTRL1_CHGDETEN_SHIFT;
166	max14577_update_reg(rmap, MAX14577_REG_CDETCTRL1,
167			CDETCTRL1_CHGDETEN_MASK | CDETCTRL1_CHGTYPMAN_MASK,
168			reg_data);
169
170	/* Battery Fast-Charge Timer, from SM-V700: 6hrs */
171	reg_data = 0x3 << CHGCTRL1_TCHW_SHIFT;
172	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL1, reg_data);
173
174	/*
175	 * Wall-Adapter Rapid Charge, default on
176	 * Battery-Charger, default on
177	 */
178	reg_data = 0x1 << CHGCTRL2_VCHGR_RC_SHIFT;
179	reg_data |= 0x1 << CHGCTRL2_MBCHOSTEN_SHIFT;
180	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL2, reg_data);
181
182	/* Battery-Charger Constant Voltage (CV) Mode, from SM-V700: 4.35V */
183	reg_data = 0xf << CHGCTRL3_MBCCVWRC_SHIFT;
184	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL3, reg_data);
185
186	/*
187	 * Fast Battery-Charge Current Low, default 200-950mA
188	 * Fast Battery-Charge Current High, from SM-V700: 450mA
189	 */
190	reg_data = 0x1 << CHGCTRL4_MBCICHWRCL_SHIFT;
191	reg_data |= 0x5 << CHGCTRL4_MBCICHWRCH_SHIFT;
192	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL4, reg_data);
193
194	/* End-of-Charge Current, from SM-V700: 50mA */
195	reg_data = 0x0 << CHGCTRL5_EOCS_SHIFT;
196	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL5, reg_data);
197
198	/* Auto Charging Stop, default off */
199	reg_data = 0x0 << CHGCTRL6_AUTOSTOP_SHIFT;
200	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL6, reg_data);
201
202	/* Overvoltage-Protection Threshold, from SM-V700: 6.5V */
203	reg_data = 0x2 << CHGCTRL7_OTPCGHCVS_SHIFT;
204	max14577_write_reg(rmap, MAX14577_REG_CHGCTRL7, reg_data);
205}
206
207/* Support property from charger */
208static enum power_supply_property max14577_charger_props[] = {
209	POWER_SUPPLY_PROP_STATUS,
210	POWER_SUPPLY_PROP_CHARGE_TYPE,
211	POWER_SUPPLY_PROP_HEALTH,
212	POWER_SUPPLY_PROP_PRESENT,
213	POWER_SUPPLY_PROP_ONLINE,
214	POWER_SUPPLY_PROP_MODEL_NAME,
215	POWER_SUPPLY_PROP_MANUFACTURER,
216};
217
218static const char *model_name = "MAX14577";
219static const char *manufacturer = "Maxim Integrated";
220
221static int max14577_charger_get_property(struct power_supply *psy,
222			    enum power_supply_property psp,
223			    union power_supply_propval *val)
224{
225	struct max14577_charger *chg = container_of(psy,
226						  struct max14577_charger,
227						  charger);
228	int ret = 0;
229
230	switch (psp) {
231	case POWER_SUPPLY_PROP_STATUS:
232		val->intval = max14577_get_charger_state(chg);
233		break;
234	case POWER_SUPPLY_PROP_CHARGE_TYPE:
235		val->intval = max14577_get_charge_type(chg);
236		break;
237	case POWER_SUPPLY_PROP_HEALTH:
238		val->intval = max14577_get_battery_health(chg);
239		break;
240	case POWER_SUPPLY_PROP_PRESENT:
241		val->intval = max14577_get_present(chg);
242		break;
243	case POWER_SUPPLY_PROP_ONLINE:
244		val->intval = max14577_get_online(chg);
245		break;
246	case POWER_SUPPLY_PROP_MODEL_NAME:
247		val->strval = model_name;
248		break;
249	case POWER_SUPPLY_PROP_MANUFACTURER:
250		val->strval = manufacturer;
251		break;
252	default:
253		return -EINVAL;
254	}
255
256	return ret;
257}
258
259static int max14577_charger_probe(struct platform_device *pdev)
260{
261	struct max14577_charger *chg;
262	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
263	int ret;
264
265	chg = devm_kzalloc(&pdev->dev, sizeof(*chg), GFP_KERNEL);
266	if (!chg)
267		return -ENOMEM;
268
269	platform_set_drvdata(pdev, chg);
270	chg->dev = &pdev->dev;
271	chg->max14577 = max14577;
272
273	max14577_charger_reg_init(chg);
274
275	chg->charger.name = "max14577-charger",
276	chg->charger.type = POWER_SUPPLY_TYPE_BATTERY,
277	chg->charger.properties = max14577_charger_props,
278	chg->charger.num_properties = ARRAY_SIZE(max14577_charger_props),
279	chg->charger.get_property = max14577_charger_get_property,
280
281	ret = power_supply_register(&pdev->dev, &chg->charger);
282	if (ret) {
283		dev_err(&pdev->dev, "failed: power supply register\n");
284		return ret;
285	}
286
287	return 0;
288}
289
290static int max14577_charger_remove(struct platform_device *pdev)
291{
292	struct max14577_charger *chg = platform_get_drvdata(pdev);
293
294	power_supply_unregister(&chg->charger);
295
296	return 0;
297}
298
299static struct platform_driver max14577_charger_driver = {
300	.driver = {
301		.owner	= THIS_MODULE,
302		.name	= "max14577-charger",
303	},
304	.probe		= max14577_charger_probe,
305	.remove		= max14577_charger_remove,
306};
307module_platform_driver(max14577_charger_driver);
308
309MODULE_AUTHOR("Krzysztof Kozlowski <k.kozlowski@samsung.com>");
310MODULE_DESCRIPTION("MAXIM 14577 charger driver");
311MODULE_LICENSE("GPL");