1 /*
2  * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
3  *
4  * Copyright (C) 2014 Intel Corporation
5  *
6  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; version 2 of the License.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the GNU
15  * General Public License for more details.
16  *
17  */
18 
19 #include <linux/dmi.h>
20 #include <linux/module.h>
21 #include <linux/kernel.h>
22 #include <linux/device.h>
23 #include <linux/regmap.h>
24 #include <linux/mfd/axp20x.h>
25 #include <linux/platform_device.h>
26 
27 #include <linux/iio/iio.h>
28 #include <linux/iio/machine.h>
29 #include <linux/iio/driver.h>
30 
31 /*
32  * This mask enables all ADCs except for the battery temp-sensor (TS), that is
33  * left as-is to avoid breaking charging on devices without a temp-sensor.
34  */
35 #define AXP288_ADC_EN_MASK				0xF0
36 #define AXP288_ADC_TS_ENABLE				0x01
37 
38 #define AXP288_ADC_TS_BIAS_MASK				GENMASK(5, 4)
39 #define AXP288_ADC_TS_BIAS_20UA				(0 << 4)
40 #define AXP288_ADC_TS_BIAS_40UA				(1 << 4)
41 #define AXP288_ADC_TS_BIAS_60UA				(2 << 4)
42 #define AXP288_ADC_TS_BIAS_80UA				(3 << 4)
43 #define AXP288_ADC_TS_CURRENT_ON_OFF_MASK		GENMASK(1, 0)
44 #define AXP288_ADC_TS_CURRENT_OFF			(0 << 0)
45 #define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING		(1 << 0)
46 #define AXP288_ADC_TS_CURRENT_ON_ONDEMAND		(2 << 0)
47 #define AXP288_ADC_TS_CURRENT_ON			(3 << 0)
48 
49 enum axp288_adc_id {
50 	AXP288_ADC_TS,
51 	AXP288_ADC_PMIC,
52 	AXP288_ADC_GP,
53 	AXP288_ADC_BATT_CHRG_I,
54 	AXP288_ADC_BATT_DISCHRG_I,
55 	AXP288_ADC_BATT_V,
56 	AXP288_ADC_NR_CHAN,
57 };
58 
59 struct axp288_adc_info {
60 	int irq;
61 	struct regmap *regmap;
62 	bool ts_enabled;
63 };
64 
65 static const struct iio_chan_spec axp288_adc_channels[] = {
66 	{
67 		.indexed = 1,
68 		.type = IIO_TEMP,
69 		.channel = 0,
70 		.address = AXP288_TS_ADC_H,
71 		.datasheet_name = "TS_PIN",
72 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
73 	}, {
74 		.indexed = 1,
75 		.type = IIO_TEMP,
76 		.channel = 1,
77 		.address = AXP288_PMIC_ADC_H,
78 		.datasheet_name = "PMIC_TEMP",
79 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
80 	}, {
81 		.indexed = 1,
82 		.type = IIO_TEMP,
83 		.channel = 2,
84 		.address = AXP288_GP_ADC_H,
85 		.datasheet_name = "GPADC",
86 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
87 	}, {
88 		.indexed = 1,
89 		.type = IIO_CURRENT,
90 		.channel = 3,
91 		.address = AXP20X_BATT_CHRG_I_H,
92 		.datasheet_name = "BATT_CHG_I",
93 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
94 	}, {
95 		.indexed = 1,
96 		.type = IIO_CURRENT,
97 		.channel = 4,
98 		.address = AXP20X_BATT_DISCHRG_I_H,
99 		.datasheet_name = "BATT_DISCHRG_I",
100 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
101 	}, {
102 		.indexed = 1,
103 		.type = IIO_VOLTAGE,
104 		.channel = 5,
105 		.address = AXP20X_BATT_V_H,
106 		.datasheet_name = "BATT_V",
107 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
108 	},
109 };
110 
111 /* for consumer drivers */
112 static struct iio_map axp288_adc_default_maps[] = {
113 	IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
114 	IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
115 	IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
116 	IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
117 	IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
118 	IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
119 	{},
120 };
121 
axp288_adc_read_channel(int * val,unsigned long address,struct regmap * regmap)122 static int axp288_adc_read_channel(int *val, unsigned long address,
123 				struct regmap *regmap)
124 {
125 	u8 buf[2];
126 
127 	if (regmap_bulk_read(regmap, address, buf, 2))
128 		return -EIO;
129 	*val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);
130 
131 	return IIO_VAL_INT;
132 }
133 
134 /*
135  * The current-source used for the battery temp-sensor (TS) is shared
136  * with the GPADC. For proper fuel-gauge and charger operation the TS
137  * current-source needs to be permanently on. But to read the GPADC we
138  * need to temporary switch the TS current-source to ondemand, so that
139  * the GPADC can use it, otherwise we will always read an all 0 value.
140  */
axp288_adc_set_ts(struct axp288_adc_info * info,unsigned int mode,unsigned long address)141 static int axp288_adc_set_ts(struct axp288_adc_info *info,
142 			     unsigned int mode, unsigned long address)
143 {
144 	int ret;
145 
146 	/* No need to switch the current-source if the TS pin is disabled */
147 	if (!info->ts_enabled)
148 		return 0;
149 
150 	/* Channels other than GPADC do not need the current source */
151 	if (address != AXP288_GP_ADC_H)
152 		return 0;
153 
154 	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
155 				 AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
156 	if (ret)
157 		return ret;
158 
159 	/* When switching to the GPADC pin give things some time to settle */
160 	if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
161 		usleep_range(6000, 10000);
162 
163 	return 0;
164 }
165 
axp288_adc_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)166 static int axp288_adc_read_raw(struct iio_dev *indio_dev,
167 			struct iio_chan_spec const *chan,
168 			int *val, int *val2, long mask)
169 {
170 	int ret;
171 	struct axp288_adc_info *info = iio_priv(indio_dev);
172 
173 	mutex_lock(&indio_dev->mlock);
174 	switch (mask) {
175 	case IIO_CHAN_INFO_RAW:
176 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
177 					chan->address)) {
178 			dev_err(&indio_dev->dev, "GPADC mode\n");
179 			ret = -EINVAL;
180 			break;
181 		}
182 		ret = axp288_adc_read_channel(val, chan->address, info->regmap);
183 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
184 						chan->address))
185 			dev_err(&indio_dev->dev, "TS pin restore\n");
186 		break;
187 	default:
188 		ret = -EINVAL;
189 	}
190 	mutex_unlock(&indio_dev->mlock);
191 
192 	return ret;
193 }
194 
195 /*
196  * We rely on the machine's firmware to correctly setup the TS pin bias current
197  * at boot. This lists systems with broken fw where we need to set it ourselves.
198  */
199 static const struct dmi_system_id axp288_adc_ts_bias_override[] = {
200 	{
201 		/* Lenovo Ideapad 100S (11 inch) */
202 		.matches = {
203 		  DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
204 		  DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo ideapad 100S-11IBY"),
205 		},
206 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
207 	},
208 	{
209 		/* Nuvision Solo 10 Draw */
210 		.matches = {
211 		  DMI_MATCH(DMI_SYS_VENDOR, "TMAX"),
212 		  DMI_MATCH(DMI_PRODUCT_NAME, "TM101W610L"),
213 		},
214 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
215 	},
216 	{}
217 };
218 
axp288_adc_initialize(struct axp288_adc_info * info)219 static int axp288_adc_initialize(struct axp288_adc_info *info)
220 {
221 	const struct dmi_system_id *bias_override;
222 	int ret, adc_enable_val;
223 
224 	bias_override = dmi_first_match(axp288_adc_ts_bias_override);
225 	if (bias_override) {
226 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
227 					 AXP288_ADC_TS_BIAS_MASK,
228 					 (uintptr_t)bias_override->driver_data);
229 		if (ret)
230 			return ret;
231 	}
232 
233 	/*
234 	 * Determine if the TS pin is enabled and set the TS current-source
235 	 * accordingly.
236 	 */
237 	ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
238 	if (ret)
239 		return ret;
240 
241 	if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
242 		info->ts_enabled = true;
243 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
244 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
245 					 AXP288_ADC_TS_CURRENT_ON);
246 	} else {
247 		info->ts_enabled = false;
248 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
249 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
250 					 AXP288_ADC_TS_CURRENT_OFF);
251 	}
252 	if (ret)
253 		return ret;
254 
255 	/* Turn on the ADC for all channels except TS, leave TS as is */
256 	return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,
257 				  AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);
258 }
259 
260 static const struct iio_info axp288_adc_iio_info = {
261 	.read_raw = &axp288_adc_read_raw,
262 };
263 
axp288_adc_probe(struct platform_device * pdev)264 static int axp288_adc_probe(struct platform_device *pdev)
265 {
266 	int ret;
267 	struct axp288_adc_info *info;
268 	struct iio_dev *indio_dev;
269 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
270 
271 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
272 	if (!indio_dev)
273 		return -ENOMEM;
274 
275 	info = iio_priv(indio_dev);
276 	info->irq = platform_get_irq(pdev, 0);
277 	if (info->irq < 0) {
278 		dev_err(&pdev->dev, "no irq resource?\n");
279 		return info->irq;
280 	}
281 	platform_set_drvdata(pdev, indio_dev);
282 	info->regmap = axp20x->regmap;
283 	/*
284 	 * Set ADC to enabled state at all time, including system suspend.
285 	 * otherwise internal fuel gauge functionality may be affected.
286 	 */
287 	ret = axp288_adc_initialize(info);
288 	if (ret) {
289 		dev_err(&pdev->dev, "unable to enable ADC device\n");
290 		return ret;
291 	}
292 
293 	indio_dev->dev.parent = &pdev->dev;
294 	indio_dev->name = pdev->name;
295 	indio_dev->channels = axp288_adc_channels;
296 	indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
297 	indio_dev->info = &axp288_adc_iio_info;
298 	indio_dev->modes = INDIO_DIRECT_MODE;
299 	ret = iio_map_array_register(indio_dev, axp288_adc_default_maps);
300 	if (ret < 0)
301 		return ret;
302 
303 	ret = iio_device_register(indio_dev);
304 	if (ret < 0) {
305 		dev_err(&pdev->dev, "unable to register iio device\n");
306 		goto err_array_unregister;
307 	}
308 	return 0;
309 
310 err_array_unregister:
311 	iio_map_array_unregister(indio_dev);
312 
313 	return ret;
314 }
315 
axp288_adc_remove(struct platform_device * pdev)316 static int axp288_adc_remove(struct platform_device *pdev)
317 {
318 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
319 
320 	iio_device_unregister(indio_dev);
321 	iio_map_array_unregister(indio_dev);
322 
323 	return 0;
324 }
325 
326 static const struct platform_device_id axp288_adc_id_table[] = {
327 	{ .name = "axp288_adc" },
328 	{},
329 };
330 
331 static struct platform_driver axp288_adc_driver = {
332 	.probe = axp288_adc_probe,
333 	.remove = axp288_adc_remove,
334 	.id_table = axp288_adc_id_table,
335 	.driver = {
336 		.name = "axp288_adc",
337 	},
338 };
339 
340 MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);
341 
342 module_platform_driver(axp288_adc_driver);
343 
344 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
345 MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
346 MODULE_LICENSE("GPL");
347