1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * axp288_adc.c - X-Powers AXP288 PMIC ADC Driver
4  *
5  * Copyright (C) 2014 Intel Corporation
6  *
7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8  */
9 
10 #include <linux/dmi.h>
11 #include <linux/module.h>
12 #include <linux/mutex.h>
13 #include <linux/kernel.h>
14 #include <linux/device.h>
15 #include <linux/regmap.h>
16 #include <linux/mfd/axp20x.h>
17 #include <linux/platform_device.h>
18 
19 #include <linux/iio/iio.h>
20 #include <linux/iio/machine.h>
21 #include <linux/iio/driver.h>
22 
23 /*
24  * This mask enables all ADCs except for the battery temp-sensor (TS), that is
25  * left as-is to avoid breaking charging on devices without a temp-sensor.
26  */
27 #define AXP288_ADC_EN_MASK				0xF0
28 #define AXP288_ADC_TS_ENABLE				0x01
29 
30 #define AXP288_ADC_TS_BIAS_MASK				GENMASK(5, 4)
31 #define AXP288_ADC_TS_BIAS_20UA				(0 << 4)
32 #define AXP288_ADC_TS_BIAS_40UA				(1 << 4)
33 #define AXP288_ADC_TS_BIAS_60UA				(2 << 4)
34 #define AXP288_ADC_TS_BIAS_80UA				(3 << 4)
35 #define AXP288_ADC_TS_CURRENT_ON_OFF_MASK		GENMASK(1, 0)
36 #define AXP288_ADC_TS_CURRENT_OFF			(0 << 0)
37 #define AXP288_ADC_TS_CURRENT_ON_WHEN_CHARGING		(1 << 0)
38 #define AXP288_ADC_TS_CURRENT_ON_ONDEMAND		(2 << 0)
39 #define AXP288_ADC_TS_CURRENT_ON			(3 << 0)
40 
41 enum axp288_adc_id {
42 	AXP288_ADC_TS,
43 	AXP288_ADC_PMIC,
44 	AXP288_ADC_GP,
45 	AXP288_ADC_BATT_CHRG_I,
46 	AXP288_ADC_BATT_DISCHRG_I,
47 	AXP288_ADC_BATT_V,
48 	AXP288_ADC_NR_CHAN,
49 };
50 
51 struct axp288_adc_info {
52 	int irq;
53 	struct regmap *regmap;
54 	/* lock to protect against multiple access to the device */
55 	struct mutex lock;
56 	bool ts_enabled;
57 };
58 
59 static const struct iio_chan_spec axp288_adc_channels[] = {
60 	{
61 		.indexed = 1,
62 		.type = IIO_TEMP,
63 		.channel = 0,
64 		.address = AXP288_TS_ADC_H,
65 		.datasheet_name = "TS_PIN",
66 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
67 	}, {
68 		.indexed = 1,
69 		.type = IIO_TEMP,
70 		.channel = 1,
71 		.address = AXP288_PMIC_ADC_H,
72 		.datasheet_name = "PMIC_TEMP",
73 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
74 	}, {
75 		.indexed = 1,
76 		.type = IIO_TEMP,
77 		.channel = 2,
78 		.address = AXP288_GP_ADC_H,
79 		.datasheet_name = "GPADC",
80 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
81 	}, {
82 		.indexed = 1,
83 		.type = IIO_CURRENT,
84 		.channel = 3,
85 		.address = AXP20X_BATT_CHRG_I_H,
86 		.datasheet_name = "BATT_CHG_I",
87 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
88 	}, {
89 		.indexed = 1,
90 		.type = IIO_CURRENT,
91 		.channel = 4,
92 		.address = AXP20X_BATT_DISCHRG_I_H,
93 		.datasheet_name = "BATT_DISCHRG_I",
94 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
95 	}, {
96 		.indexed = 1,
97 		.type = IIO_VOLTAGE,
98 		.channel = 5,
99 		.address = AXP20X_BATT_V_H,
100 		.datasheet_name = "BATT_V",
101 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
102 	},
103 };
104 
105 /* for consumer drivers */
106 static struct iio_map axp288_adc_default_maps[] = {
107 	IIO_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
108 	IIO_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
109 	IIO_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
110 	IIO_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
111 	IIO_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
112 	IIO_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
113 	{},
114 };
115 
axp288_adc_read_channel(int * val,unsigned long address,struct regmap * regmap)116 static int axp288_adc_read_channel(int *val, unsigned long address,
117 				struct regmap *regmap)
118 {
119 	u8 buf[2];
120 
121 	if (regmap_bulk_read(regmap, address, buf, 2))
122 		return -EIO;
123 	*val = (buf[0] << 4) + ((buf[1] >> 4) & 0x0F);
124 
125 	return IIO_VAL_INT;
126 }
127 
128 /*
129  * The current-source used for the battery temp-sensor (TS) is shared
130  * with the GPADC. For proper fuel-gauge and charger operation the TS
131  * current-source needs to be permanently on. But to read the GPADC we
132  * need to temporary switch the TS current-source to ondemand, so that
133  * the GPADC can use it, otherwise we will always read an all 0 value.
134  */
axp288_adc_set_ts(struct axp288_adc_info * info,unsigned int mode,unsigned long address)135 static int axp288_adc_set_ts(struct axp288_adc_info *info,
136 			     unsigned int mode, unsigned long address)
137 {
138 	int ret;
139 
140 	/* No need to switch the current-source if the TS pin is disabled */
141 	if (!info->ts_enabled)
142 		return 0;
143 
144 	/* Channels other than GPADC do not need the current source */
145 	if (address != AXP288_GP_ADC_H)
146 		return 0;
147 
148 	ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
149 				 AXP288_ADC_TS_CURRENT_ON_OFF_MASK, mode);
150 	if (ret)
151 		return ret;
152 
153 	/* When switching to the GPADC pin give things some time to settle */
154 	if (mode == AXP288_ADC_TS_CURRENT_ON_ONDEMAND)
155 		usleep_range(6000, 10000);
156 
157 	return 0;
158 }
159 
axp288_adc_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)160 static int axp288_adc_read_raw(struct iio_dev *indio_dev,
161 			struct iio_chan_spec const *chan,
162 			int *val, int *val2, long mask)
163 {
164 	int ret;
165 	struct axp288_adc_info *info = iio_priv(indio_dev);
166 
167 	mutex_lock(&info->lock);
168 	switch (mask) {
169 	case IIO_CHAN_INFO_RAW:
170 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON_ONDEMAND,
171 					chan->address)) {
172 			dev_err(&indio_dev->dev, "GPADC mode\n");
173 			ret = -EINVAL;
174 			break;
175 		}
176 		ret = axp288_adc_read_channel(val, chan->address, info->regmap);
177 		if (axp288_adc_set_ts(info, AXP288_ADC_TS_CURRENT_ON,
178 						chan->address))
179 			dev_err(&indio_dev->dev, "TS pin restore\n");
180 		break;
181 	default:
182 		ret = -EINVAL;
183 	}
184 	mutex_unlock(&info->lock);
185 
186 	return ret;
187 }
188 
189 /*
190  * We rely on the machine's firmware to correctly setup the TS pin bias current
191  * at boot. This lists systems with broken fw where we need to set it ourselves.
192  */
193 static const struct dmi_system_id axp288_adc_ts_bias_override[] = {
194 	{
195 		/* Lenovo Ideapad 100S (11 inch) */
196 		.matches = {
197 		  DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
198 		  DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo ideapad 100S-11IBY"),
199 		},
200 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
201 	},
202 	{
203 		/* Nuvision Solo 10 Draw */
204 		.matches = {
205 		  DMI_MATCH(DMI_SYS_VENDOR, "TMAX"),
206 		  DMI_MATCH(DMI_PRODUCT_NAME, "TM101W610L"),
207 		},
208 		.driver_data = (void *)(uintptr_t)AXP288_ADC_TS_BIAS_80UA,
209 	},
210 	{}
211 };
212 
axp288_adc_initialize(struct axp288_adc_info * info)213 static int axp288_adc_initialize(struct axp288_adc_info *info)
214 {
215 	const struct dmi_system_id *bias_override;
216 	int ret, adc_enable_val;
217 
218 	bias_override = dmi_first_match(axp288_adc_ts_bias_override);
219 	if (bias_override) {
220 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
221 					 AXP288_ADC_TS_BIAS_MASK,
222 					 (uintptr_t)bias_override->driver_data);
223 		if (ret)
224 			return ret;
225 	}
226 
227 	/*
228 	 * Determine if the TS pin is enabled and set the TS current-source
229 	 * accordingly.
230 	 */
231 	ret = regmap_read(info->regmap, AXP20X_ADC_EN1, &adc_enable_val);
232 	if (ret)
233 		return ret;
234 
235 	if (adc_enable_val & AXP288_ADC_TS_ENABLE) {
236 		info->ts_enabled = true;
237 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
238 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
239 					 AXP288_ADC_TS_CURRENT_ON);
240 	} else {
241 		info->ts_enabled = false;
242 		ret = regmap_update_bits(info->regmap, AXP288_ADC_TS_PIN_CTRL,
243 					 AXP288_ADC_TS_CURRENT_ON_OFF_MASK,
244 					 AXP288_ADC_TS_CURRENT_OFF);
245 	}
246 	if (ret)
247 		return ret;
248 
249 	/* Turn on the ADC for all channels except TS, leave TS as is */
250 	return regmap_update_bits(info->regmap, AXP20X_ADC_EN1,
251 				  AXP288_ADC_EN_MASK, AXP288_ADC_EN_MASK);
252 }
253 
254 static const struct iio_info axp288_adc_iio_info = {
255 	.read_raw = &axp288_adc_read_raw,
256 };
257 
axp288_adc_probe(struct platform_device * pdev)258 static int axp288_adc_probe(struct platform_device *pdev)
259 {
260 	int ret;
261 	struct axp288_adc_info *info;
262 	struct iio_dev *indio_dev;
263 	struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
264 
265 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
266 	if (!indio_dev)
267 		return -ENOMEM;
268 
269 	info = iio_priv(indio_dev);
270 	info->irq = platform_get_irq(pdev, 0);
271 	if (info->irq < 0)
272 		return info->irq;
273 
274 	info->regmap = axp20x->regmap;
275 	/*
276 	 * Set ADC to enabled state at all time, including system suspend.
277 	 * otherwise internal fuel gauge functionality may be affected.
278 	 */
279 	ret = axp288_adc_initialize(info);
280 	if (ret) {
281 		dev_err(&pdev->dev, "unable to enable ADC device\n");
282 		return ret;
283 	}
284 
285 	indio_dev->name = pdev->name;
286 	indio_dev->channels = axp288_adc_channels;
287 	indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
288 	indio_dev->info = &axp288_adc_iio_info;
289 	indio_dev->modes = INDIO_DIRECT_MODE;
290 
291 	ret = devm_iio_map_array_register(&pdev->dev, indio_dev, axp288_adc_default_maps);
292 	if (ret < 0)
293 		return ret;
294 
295 	mutex_init(&info->lock);
296 
297 	return devm_iio_device_register(&pdev->dev, indio_dev);
298 }
299 
300 static const struct platform_device_id axp288_adc_id_table[] = {
301 	{ .name = "axp288_adc" },
302 	{},
303 };
304 
305 static struct platform_driver axp288_adc_driver = {
306 	.probe = axp288_adc_probe,
307 	.id_table = axp288_adc_id_table,
308 	.driver = {
309 		.name = "axp288_adc",
310 	},
311 };
312 
313 MODULE_DEVICE_TABLE(platform, axp288_adc_id_table);
314 
315 module_platform_driver(axp288_adc_driver);
316 
317 MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@linux.intel.com>");
318 MODULE_DESCRIPTION("X-Powers AXP288 ADC Driver");
319 MODULE_LICENSE("GPL");
320