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
22enum 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
36struct 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
49static 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
81static struct max1111_data *the_max1111;
82
83int max1111_read_channel(int channel);
84int 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}
91EXPORT_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 */
99static 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
105static 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
126static DEVICE_ATTR_RO(name);
127static MAX1111_ADC_ATTR(0);
128static MAX1111_ADC_ATTR(1);
129static MAX1111_ADC_ATTR(2);
130static MAX1111_ADC_ATTR(3);
131static MAX1111_ADC_ATTR(4);
132static MAX1111_ADC_ATTR(5);
133static MAX1111_ADC_ATTR(6);
134static MAX1111_ADC_ATTR(7);
135
136static 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
145static const struct attribute_group max1111_attr_group = {
146	.attrs	= max1111_attributes,
147};
148
149static 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
157static const struct attribute_group max1110_attr_group = {
158	.attrs	= max1110_attributes,
159};
160
161static 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
183static 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
252err_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
258static 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
271static const struct spi_device_id max1111_ids[] = {
272	{ "max1110", max1110 },
273	{ "max1111", max1111 },
274	{ "max1112", max1112 },
275	{ "max1113", max1113 },
276	{ },
277};
278MODULE_DEVICE_TABLE(spi, max1111_ids);
279
280static 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
289module_spi_driver(max1111_driver);
290
291MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
292MODULE_DESCRIPTION("MAX1110/MAX1111/MAX1112/MAX1113 ADC Driver");
293MODULE_LICENSE("GPL");
294