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