1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * max1111.c - +2.7V, Low-Power, Multichannel, Serial 8-bit ADCs |
4 | * |
5 | * Based on arch/arm/mach-pxa/corgi_ssp.c |
6 | * |
7 | * Copyright (C) 2004-2005 Richard Purdie |
8 | * |
9 | * Copyright (C) 2008 Marvell International Ltd. |
10 | * Eric Miao <eric.miao@marvell.com> |
11 | */ |
12 | |
13 | #include <linux/module.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/init.h> |
16 | #include <linux/err.h> |
17 | #include <linux/hwmon.h> |
18 | #include <linux/hwmon-sysfs.h> |
19 | #include <linux/spi/spi.h> |
20 | #include <linux/slab.h> |
21 | |
22 | enum chips { max1110, max1111, max1112, max1113 }; |
23 | |
24 | #define MAX1111_TX_BUF_SIZE 1 |
25 | #define MAX1111_RX_BUF_SIZE 2 |
26 | |
27 | /* MAX1111 Commands */ |
28 | #define MAX1111_CTRL_PD0 (1u << 0) |
29 | #define MAX1111_CTRL_PD1 (1u << 1) |
30 | #define MAX1111_CTRL_SGL (1u << 2) |
31 | #define MAX1111_CTRL_UNI (1u << 3) |
32 | #define MAX1110_CTRL_SEL_SH (4) |
33 | #define MAX1111_CTRL_SEL_SH (5) /* NOTE: bit 4 is ignored */ |
34 | #define MAX1111_CTRL_STR (1u << 7) |
35 | |
36 | struct max1111_data { |
37 | struct spi_device *spi; |
38 | struct device *hwmon_dev; |
39 | struct spi_message msg; |
40 | struct spi_transfer xfer[2]; |
41 | uint8_t tx_buf[MAX1111_TX_BUF_SIZE]; |
42 | uint8_t rx_buf[MAX1111_RX_BUF_SIZE]; |
43 | struct mutex drvdata_lock; |
44 | /* protect msg, xfer and buffers from multiple access */ |
45 | int sel_sh; |
46 | int lsb; |
47 | }; |
48 | |
49 | static int max1111_read(struct device *dev, int channel) |
50 | { |
51 | struct max1111_data *data = dev_get_drvdata(dev); |
52 | uint8_t v1, v2; |
53 | int err; |
54 | |
55 | /* writing to drvdata struct is not thread safe, wait on mutex */ |
56 | mutex_lock(&data->drvdata_lock); |
57 | |
58 | data->tx_buf[0] = (channel << data->sel_sh) | |
59 | MAX1111_CTRL_PD0 | MAX1111_CTRL_PD1 | |
60 | MAX1111_CTRL_SGL | MAX1111_CTRL_UNI | MAX1111_CTRL_STR; |
61 | |
62 | err = spi_sync(spi: data->spi, message: &data->msg); |
63 | if (err < 0) { |
64 | dev_err(dev, "spi_sync failed with %d\n" , err); |
65 | mutex_unlock(lock: &data->drvdata_lock); |
66 | return err; |
67 | } |
68 | |
69 | v1 = data->rx_buf[0]; |
70 | v2 = data->rx_buf[1]; |
71 | |
72 | mutex_unlock(lock: &data->drvdata_lock); |
73 | |
74 | if ((v1 & 0xc0) || (v2 & 0x3f)) |
75 | return -EINVAL; |
76 | |
77 | return (v1 << 2) | (v2 >> 6); |
78 | } |
79 | |
80 | #ifdef CONFIG_SHARPSL_PM |
81 | static struct max1111_data *the_max1111; |
82 | |
83 | int max1111_read_channel(int channel); |
84 | int max1111_read_channel(int channel) |
85 | { |
86 | if (!the_max1111 || !the_max1111->spi) |
87 | return -ENODEV; |
88 | |
89 | return max1111_read(&the_max1111->spi->dev, channel); |
90 | } |
91 | EXPORT_SYMBOL(max1111_read_channel); |
92 | #endif |
93 | |
94 | /* |
95 | * NOTE: SPI devices do not have a default 'name' attribute, which is |
96 | * likely to be used by hwmon applications to distinguish between |
97 | * different devices, explicitly add a name attribute here. |
98 | */ |
99 | static ssize_t name_show(struct device *dev, |
100 | struct device_attribute *attr, char *buf) |
101 | { |
102 | return sprintf(buf, fmt: "%s\n" , to_spi_device(dev)->modalias); |
103 | } |
104 | |
105 | static ssize_t show_adc(struct device *dev, |
106 | struct device_attribute *attr, char *buf) |
107 | { |
108 | struct max1111_data *data = dev_get_drvdata(dev); |
109 | int channel = to_sensor_dev_attr(attr)->index; |
110 | int ret; |
111 | |
112 | ret = max1111_read(dev, channel); |
113 | if (ret < 0) |
114 | return ret; |
115 | |
116 | /* |
117 | * Assume the reference voltage to be 2.048V or 4.096V, with an 8-bit |
118 | * sample. The LSB weight is 8mV or 16mV depending on the chip type. |
119 | */ |
120 | return sprintf(buf, fmt: "%d\n" , ret * data->lsb); |
121 | } |
122 | |
123 | #define MAX1111_ADC_ATTR(_id) \ |
124 | SENSOR_DEVICE_ATTR(in##_id##_input, S_IRUGO, show_adc, NULL, _id) |
125 | |
126 | static DEVICE_ATTR_RO(name); |
127 | static MAX1111_ADC_ATTR(0); |
128 | static MAX1111_ADC_ATTR(1); |
129 | static MAX1111_ADC_ATTR(2); |
130 | static MAX1111_ADC_ATTR(3); |
131 | static MAX1111_ADC_ATTR(4); |
132 | static MAX1111_ADC_ATTR(5); |
133 | static MAX1111_ADC_ATTR(6); |
134 | static MAX1111_ADC_ATTR(7); |
135 | |
136 | static struct attribute *max1111_attributes[] = { |
137 | &dev_attr_name.attr, |
138 | &sensor_dev_attr_in0_input.dev_attr.attr, |
139 | &sensor_dev_attr_in1_input.dev_attr.attr, |
140 | &sensor_dev_attr_in2_input.dev_attr.attr, |
141 | &sensor_dev_attr_in3_input.dev_attr.attr, |
142 | NULL, |
143 | }; |
144 | |
145 | static const struct attribute_group max1111_attr_group = { |
146 | .attrs = max1111_attributes, |
147 | }; |
148 | |
149 | static struct attribute *max1110_attributes[] = { |
150 | &sensor_dev_attr_in4_input.dev_attr.attr, |
151 | &sensor_dev_attr_in5_input.dev_attr.attr, |
152 | &sensor_dev_attr_in6_input.dev_attr.attr, |
153 | &sensor_dev_attr_in7_input.dev_attr.attr, |
154 | NULL, |
155 | }; |
156 | |
157 | static const struct attribute_group max1110_attr_group = { |
158 | .attrs = max1110_attributes, |
159 | }; |
160 | |
161 | static int setup_transfer(struct max1111_data *data) |
162 | { |
163 | struct spi_message *m; |
164 | struct spi_transfer *x; |
165 | |
166 | m = &data->msg; |
167 | x = &data->xfer[0]; |
168 | |
169 | spi_message_init(m); |
170 | |
171 | x->tx_buf = &data->tx_buf[0]; |
172 | x->len = MAX1111_TX_BUF_SIZE; |
173 | spi_message_add_tail(t: x, m); |
174 | |
175 | x++; |
176 | x->rx_buf = &data->rx_buf[0]; |
177 | x->len = MAX1111_RX_BUF_SIZE; |
178 | spi_message_add_tail(t: x, m); |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | static int max1111_probe(struct spi_device *spi) |
184 | { |
185 | enum chips chip = spi_get_device_id(sdev: spi)->driver_data; |
186 | struct max1111_data *data; |
187 | int err; |
188 | |
189 | spi->bits_per_word = 8; |
190 | spi->mode = SPI_MODE_0; |
191 | err = spi_setup(spi); |
192 | if (err < 0) |
193 | return err; |
194 | |
195 | data = devm_kzalloc(dev: &spi->dev, size: sizeof(struct max1111_data), GFP_KERNEL); |
196 | if (data == NULL) |
197 | return -ENOMEM; |
198 | |
199 | switch (chip) { |
200 | case max1110: |
201 | data->lsb = 8; |
202 | data->sel_sh = MAX1110_CTRL_SEL_SH; |
203 | break; |
204 | case max1111: |
205 | data->lsb = 8; |
206 | data->sel_sh = MAX1111_CTRL_SEL_SH; |
207 | break; |
208 | case max1112: |
209 | data->lsb = 16; |
210 | data->sel_sh = MAX1110_CTRL_SEL_SH; |
211 | break; |
212 | case max1113: |
213 | data->lsb = 16; |
214 | data->sel_sh = MAX1111_CTRL_SEL_SH; |
215 | break; |
216 | } |
217 | err = setup_transfer(data); |
218 | if (err) |
219 | return err; |
220 | |
221 | mutex_init(&data->drvdata_lock); |
222 | |
223 | data->spi = spi; |
224 | spi_set_drvdata(spi, data); |
225 | |
226 | err = sysfs_create_group(kobj: &spi->dev.kobj, grp: &max1111_attr_group); |
227 | if (err) { |
228 | dev_err(&spi->dev, "failed to create attribute group\n" ); |
229 | return err; |
230 | } |
231 | if (chip == max1110 || chip == max1112) { |
232 | err = sysfs_create_group(kobj: &spi->dev.kobj, grp: &max1110_attr_group); |
233 | if (err) { |
234 | dev_err(&spi->dev, |
235 | "failed to create extended attribute group\n" ); |
236 | goto err_remove; |
237 | } |
238 | } |
239 | |
240 | data->hwmon_dev = hwmon_device_register(dev: &spi->dev); |
241 | if (IS_ERR(ptr: data->hwmon_dev)) { |
242 | dev_err(&spi->dev, "failed to create hwmon device\n" ); |
243 | err = PTR_ERR(ptr: data->hwmon_dev); |
244 | goto err_remove; |
245 | } |
246 | |
247 | #ifdef CONFIG_SHARPSL_PM |
248 | the_max1111 = data; |
249 | #endif |
250 | return 0; |
251 | |
252 | err_remove: |
253 | sysfs_remove_group(kobj: &spi->dev.kobj, grp: &max1110_attr_group); |
254 | sysfs_remove_group(kobj: &spi->dev.kobj, grp: &max1111_attr_group); |
255 | return err; |
256 | } |
257 | |
258 | static void max1111_remove(struct spi_device *spi) |
259 | { |
260 | struct max1111_data *data = spi_get_drvdata(spi); |
261 | |
262 | #ifdef CONFIG_SHARPSL_PM |
263 | the_max1111 = NULL; |
264 | #endif |
265 | hwmon_device_unregister(dev: data->hwmon_dev); |
266 | sysfs_remove_group(kobj: &spi->dev.kobj, grp: &max1110_attr_group); |
267 | sysfs_remove_group(kobj: &spi->dev.kobj, grp: &max1111_attr_group); |
268 | mutex_destroy(lock: &data->drvdata_lock); |
269 | } |
270 | |
271 | static const struct spi_device_id max1111_ids[] = { |
272 | { "max1110" , max1110 }, |
273 | { "max1111" , max1111 }, |
274 | { "max1112" , max1112 }, |
275 | { "max1113" , max1113 }, |
276 | { }, |
277 | }; |
278 | MODULE_DEVICE_TABLE(spi, max1111_ids); |
279 | |
280 | static struct spi_driver max1111_driver = { |
281 | .driver = { |
282 | .name = "max1111" , |
283 | }, |
284 | .id_table = max1111_ids, |
285 | .probe = max1111_probe, |
286 | .remove = max1111_remove, |
287 | }; |
288 | |
289 | module_spi_driver(max1111_driver); |
290 | |
291 | MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>" ); |
292 | MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver" ); |
293 | MODULE_LICENSE("GPL" ); |
294 | |