xref: /openbmc/linux/drivers/hwmon/max1111.c (revision a9ae9c52)
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 
max1111_read(struct device * dev,int channel)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(data->spi, &data->msg);
63 	if (err < 0) {
64 		dev_err(dev, "spi_sync failed with %d\n", err);
65 		mutex_unlock(&data->drvdata_lock);
66 		return err;
67 	}
68 
69 	v1 = data->rx_buf[0];
70 	v2 = data->rx_buf[1];
71 
72 	mutex_unlock(&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);
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  */
name_show(struct device * dev,struct device_attribute * attr,char * buf)99 static ssize_t name_show(struct device *dev,
100 			 struct device_attribute *attr, char *buf)
101 {
102 	return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
103 }
104 
show_adc(struct device * dev,struct device_attribute * attr,char * buf)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, "%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 
setup_transfer(struct max1111_data * data)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(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(x, m);
179 
180 	return 0;
181 }
182 
max1111_probe(struct spi_device * spi)183 static int max1111_probe(struct spi_device *spi)
184 {
185 	enum chips chip = spi_get_device_id(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(&spi->dev, 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(&spi->dev.kobj, &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(&spi->dev.kobj, &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(&spi->dev);
241 	if (IS_ERR(data->hwmon_dev)) {
242 		dev_err(&spi->dev, "failed to create hwmon device\n");
243 		err = PTR_ERR(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(&spi->dev.kobj, &max1110_attr_group);
254 	sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
255 	return err;
256 }
257 
max1111_remove(struct spi_device * spi)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(data->hwmon_dev);
266 	sysfs_remove_group(&spi->dev.kobj, &max1110_attr_group);
267 	sysfs_remove_group(&spi->dev.kobj, &max1111_attr_group);
268 	mutex_destroy(&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