1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * ADC driver for the RICOH RN5T618 power management chip family
4 *
5 * Copyright (C) 2019 Andreas Kemnade
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/device.h>
10 #include <linux/errno.h>
11 #include <linux/interrupt.h>
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/mfd/rn5t618.h>
15 #include <linux/platform_device.h>
16 #include <linux/completion.h>
17 #include <linux/regmap.h>
18 #include <linux/iio/iio.h>
19 #include <linux/iio/driver.h>
20 #include <linux/iio/machine.h>
21 #include <linux/slab.h>
22
23 #define RN5T618_ADC_CONVERSION_TIMEOUT (msecs_to_jiffies(500))
24 #define RN5T618_REFERENCE_VOLT 2500
25
26 /* mask for selecting channels for single conversion */
27 #define RN5T618_ADCCNT3_CHANNEL_MASK 0x7
28 /* average 4-time conversion mode */
29 #define RN5T618_ADCCNT3_AVG BIT(3)
30 /* set for starting a single conversion, gets cleared by hw when done */
31 #define RN5T618_ADCCNT3_GODONE BIT(4)
32 /* automatic conversion, period is in ADCCNT2, selected channels are
33 * in ADCCNT1
34 */
35 #define RN5T618_ADCCNT3_AUTO BIT(5)
36 #define RN5T618_ADCEND_IRQ BIT(0)
37
38 struct rn5t618_adc_data {
39 struct device *dev;
40 struct rn5t618 *rn5t618;
41 struct completion conv_completion;
42 int irq;
43 };
44
45 enum rn5t618_channels {
46 LIMMON = 0,
47 VBAT,
48 VADP,
49 VUSB,
50 VSYS,
51 VTHM,
52 AIN1,
53 AIN0
54 };
55
56 static const struct u16_fract rn5t618_ratios[8] = {
57 [LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
58 [VBAT] = {2, 1},
59 [VADP] = {3, 1},
60 [VUSB] = {3, 1},
61 [VSYS] = {3, 1},
62 [VTHM] = {1, 1},
63 [AIN1] = {1, 1},
64 [AIN0] = {1, 1},
65 };
66
rn5t618_read_adc_reg(struct rn5t618 * rn5t618,int reg,u16 * val)67 static int rn5t618_read_adc_reg(struct rn5t618 *rn5t618, int reg, u16 *val)
68 {
69 u8 data[2];
70 int ret;
71
72 ret = regmap_bulk_read(rn5t618->regmap, reg, data, sizeof(data));
73 if (ret < 0)
74 return ret;
75
76 *val = (data[0] << 4) | (data[1] & 0xF);
77
78 return 0;
79 }
80
rn5t618_adc_irq(int irq,void * data)81 static irqreturn_t rn5t618_adc_irq(int irq, void *data)
82 {
83 struct rn5t618_adc_data *adc = data;
84 unsigned int r = 0;
85 int ret;
86
87 /* clear low & high threshold irqs */
88 regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC1, 0);
89 regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC2, 0);
90
91 ret = regmap_read(adc->rn5t618->regmap, RN5T618_IR_ADC3, &r);
92 if (ret < 0)
93 dev_err(adc->dev, "failed to read IRQ status: %d\n", ret);
94
95 regmap_write(adc->rn5t618->regmap, RN5T618_IR_ADC3, 0);
96
97 if (r & RN5T618_ADCEND_IRQ)
98 complete(&adc->conv_completion);
99
100 return IRQ_HANDLED;
101 }
102
rn5t618_adc_read(struct iio_dev * iio_dev,const struct iio_chan_spec * chan,int * val,int * val2,long mask)103 static int rn5t618_adc_read(struct iio_dev *iio_dev,
104 const struct iio_chan_spec *chan,
105 int *val, int *val2, long mask)
106 {
107 struct rn5t618_adc_data *adc = iio_priv(iio_dev);
108 u16 raw;
109 int ret;
110
111 if (mask == IIO_CHAN_INFO_SCALE) {
112 *val = RN5T618_REFERENCE_VOLT *
113 rn5t618_ratios[chan->channel].numerator;
114 *val2 = rn5t618_ratios[chan->channel].denominator * 4095;
115
116 return IIO_VAL_FRACTIONAL;
117 }
118
119 /* select channel */
120 ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
121 RN5T618_ADCCNT3_CHANNEL_MASK,
122 chan->channel);
123 if (ret < 0)
124 return ret;
125
126 ret = regmap_write(adc->rn5t618->regmap, RN5T618_EN_ADCIR3,
127 RN5T618_ADCEND_IRQ);
128 if (ret < 0)
129 return ret;
130
131 ret = regmap_update_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
132 RN5T618_ADCCNT3_AVG,
133 mask == IIO_CHAN_INFO_AVERAGE_RAW ?
134 RN5T618_ADCCNT3_AVG : 0);
135 if (ret < 0)
136 return ret;
137
138 init_completion(&adc->conv_completion);
139 /* single conversion */
140 ret = regmap_set_bits(adc->rn5t618->regmap, RN5T618_ADCCNT3,
141 RN5T618_ADCCNT3_GODONE);
142 if (ret < 0)
143 return ret;
144
145 ret = wait_for_completion_timeout(&adc->conv_completion,
146 RN5T618_ADC_CONVERSION_TIMEOUT);
147 if (ret == 0) {
148 dev_warn(adc->dev, "timeout waiting for adc result\n");
149 return -ETIMEDOUT;
150 }
151
152 ret = rn5t618_read_adc_reg(adc->rn5t618,
153 RN5T618_ILIMDATAH + 2 * chan->channel,
154 &raw);
155 if (ret < 0)
156 return ret;
157
158 *val = raw;
159
160 return IIO_VAL_INT;
161 }
162
163 static const struct iio_info rn5t618_adc_iio_info = {
164 .read_raw = &rn5t618_adc_read,
165 };
166
167 #define RN5T618_ADC_CHANNEL(_channel, _type, _name) { \
168 .type = _type, \
169 .channel = _channel, \
170 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
171 BIT(IIO_CHAN_INFO_AVERAGE_RAW) | \
172 BIT(IIO_CHAN_INFO_SCALE), \
173 .datasheet_name = _name, \
174 .indexed = 1. \
175 }
176
177 static const struct iio_chan_spec rn5t618_adc_iio_channels[] = {
178 RN5T618_ADC_CHANNEL(LIMMON, IIO_CURRENT, "LIMMON"),
179 RN5T618_ADC_CHANNEL(VBAT, IIO_VOLTAGE, "VBAT"),
180 RN5T618_ADC_CHANNEL(VADP, IIO_VOLTAGE, "VADP"),
181 RN5T618_ADC_CHANNEL(VUSB, IIO_VOLTAGE, "VUSB"),
182 RN5T618_ADC_CHANNEL(VSYS, IIO_VOLTAGE, "VSYS"),
183 RN5T618_ADC_CHANNEL(VTHM, IIO_VOLTAGE, "VTHM"),
184 RN5T618_ADC_CHANNEL(AIN1, IIO_VOLTAGE, "AIN1"),
185 RN5T618_ADC_CHANNEL(AIN0, IIO_VOLTAGE, "AIN0")
186 };
187
188 static struct iio_map rn5t618_maps[] = {
189 IIO_MAP("VADP", "rn5t618-power", "vadp"),
190 IIO_MAP("VUSB", "rn5t618-power", "vusb"),
191 { /* sentinel */ }
192 };
193
rn5t618_adc_probe(struct platform_device * pdev)194 static int rn5t618_adc_probe(struct platform_device *pdev)
195 {
196 int ret;
197 struct iio_dev *iio_dev;
198 struct rn5t618_adc_data *adc;
199 struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
200
201 iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
202 if (!iio_dev) {
203 dev_err(&pdev->dev, "failed allocating iio device\n");
204 return -ENOMEM;
205 }
206
207 adc = iio_priv(iio_dev);
208 adc->dev = &pdev->dev;
209 adc->rn5t618 = rn5t618;
210
211 if (rn5t618->irq_data)
212 adc->irq = regmap_irq_get_virq(rn5t618->irq_data,
213 RN5T618_IRQ_ADC);
214
215 if (adc->irq <= 0) {
216 dev_err(&pdev->dev, "get virq failed\n");
217 return -EINVAL;
218 }
219
220 init_completion(&adc->conv_completion);
221
222 iio_dev->name = dev_name(&pdev->dev);
223 iio_dev->info = &rn5t618_adc_iio_info;
224 iio_dev->modes = INDIO_DIRECT_MODE;
225 iio_dev->channels = rn5t618_adc_iio_channels;
226 iio_dev->num_channels = ARRAY_SIZE(rn5t618_adc_iio_channels);
227
228 /* stop any auto-conversion */
229 ret = regmap_write(rn5t618->regmap, RN5T618_ADCCNT3, 0);
230 if (ret < 0)
231 return ret;
232
233 platform_set_drvdata(pdev, iio_dev);
234
235 ret = devm_request_threaded_irq(adc->dev, adc->irq, NULL,
236 rn5t618_adc_irq,
237 IRQF_ONESHOT, dev_name(adc->dev),
238 adc);
239 if (ret < 0) {
240 dev_err(adc->dev, "request irq %d failed: %d\n", adc->irq, ret);
241 return ret;
242 }
243
244 ret = devm_iio_map_array_register(adc->dev, iio_dev, rn5t618_maps);
245 if (ret < 0)
246 return ret;
247
248 return devm_iio_device_register(adc->dev, iio_dev);
249 }
250
251 static struct platform_driver rn5t618_adc_driver = {
252 .driver = {
253 .name = "rn5t618-adc",
254 },
255 .probe = rn5t618_adc_probe,
256 };
257
258 module_platform_driver(rn5t618_adc_driver);
259 MODULE_ALIAS("platform:rn5t618-adc");
260 MODULE_DESCRIPTION("RICOH RN5T618 ADC driver");
261 MODULE_LICENSE("GPL");
262