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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2006 Juergen Beisert, Pengutronix
4 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
5 * Copyright (C) 2009 Wolfram Sang, Pengutronix
6 *
7 * The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
8 * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
9 * details
10 * Note:
11 * - DIN must be stable at the rising edge of clock.
12 * - when writing:
13 * - always clock in 16 clocks at once
14 * - at DIN: D15 first, D0 last
15 * - D0..D7 = databyte, D8..D14 = commandbyte
16 * - D15 = low -> write command
17 * - when reading
18 * - always clock in 16 clocks at once
19 * - at DIN: D15 first, D0 last
20 * - D0..D7 = dummy, D8..D14 = register address
21 * - D15 = high -> read command
22 * - raise CS and assert it again
23 * - always clock in 16 clocks at once
24 * - at DOUT: D15 first, D0 last
25 * - D0..D7 contains the data from the first cycle
26 *
27 * The driver exports a standard gpiochip interface
28 */
29
30#include <linux/module.h>
31#include <linux/init.h>
32#include <linux/platform_device.h>
33#include <linux/mutex.h>
34#include <linux/spi/max7301.h>
35#include <linux/gpio/driver.h>
36#include <linux/slab.h>
37
38/*
39 * Pin configurations, see MAX7301 datasheet page 6
40 */
41#define PIN_CONFIG_MASK 0x03
42#define PIN_CONFIG_IN_PULLUP 0x03
43#define PIN_CONFIG_IN_WO_PULLUP 0x02
44#define PIN_CONFIG_OUT 0x01
45
46#define PIN_NUMBER 28
47
48static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
49{
50 struct max7301 *ts = container_of(chip, struct max7301, chip);
51 u8 *config;
52 u8 offset_bits, pin_config;
53 int ret;
54
55 /* First 4 pins are unused in the controller */
56 offset += 4;
57 offset_bits = (offset & 3) << 1;
58
59 config = &ts->port_config[offset >> 2];
60
61 if (ts->input_pullup_active & BIT(offset))
62 pin_config = PIN_CONFIG_IN_PULLUP;
63 else
64 pin_config = PIN_CONFIG_IN_WO_PULLUP;
65
66 mutex_lock(&ts->lock);
67
68 *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
69 | (pin_config << offset_bits);
70
71 ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
72
73 mutex_unlock(&ts->lock);
74
75 return ret;
76}
77
78static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
79{
80 if (value) {
81 ts->out_level |= 1 << offset;
82 return ts->write(ts->dev, 0x20 + offset, 0x01);
83 } else {
84 ts->out_level &= ~(1 << offset);
85 return ts->write(ts->dev, 0x20 + offset, 0x00);
86 }
87}
88
89static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
90 int value)
91{
92 struct max7301 *ts = container_of(chip, struct max7301, chip);
93 u8 *config;
94 u8 offset_bits;
95 int ret;
96
97 /* First 4 pins are unused in the controller */
98 offset += 4;
99 offset_bits = (offset & 3) << 1;
100
101 config = &ts->port_config[offset >> 2];
102
103 mutex_lock(&ts->lock);
104
105 *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
106 | (PIN_CONFIG_OUT << offset_bits);
107
108 ret = __max7301_set(ts, offset, value);
109
110 if (!ret)
111 ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
112
113 mutex_unlock(&ts->lock);
114
115 return ret;
116}
117
118static int max7301_get(struct gpio_chip *chip, unsigned offset)
119{
120 struct max7301 *ts = gpiochip_get_data(chip);
121 int config, level = -EINVAL;
122
123 /* First 4 pins are unused in the controller */
124 offset += 4;
125
126 mutex_lock(&ts->lock);
127
128 config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
129 & PIN_CONFIG_MASK;
130
131 switch (config) {
132 case PIN_CONFIG_OUT:
133 /* Output: return cached level */
134 level = !!(ts->out_level & (1 << offset));
135 break;
136 case PIN_CONFIG_IN_WO_PULLUP:
137 case PIN_CONFIG_IN_PULLUP:
138 /* Input: read out */
139 level = ts->read(ts->dev, 0x20 + offset) & 0x01;
140 }
141 mutex_unlock(&ts->lock);
142
143 return level;
144}
145
146static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
147{
148 struct max7301 *ts = gpiochip_get_data(chip);
149
150 /* First 4 pins are unused in the controller */
151 offset += 4;
152
153 mutex_lock(&ts->lock);
154
155 __max7301_set(ts, offset, value);
156
157 mutex_unlock(&ts->lock);
158}
159
160int __max730x_probe(struct max7301 *ts)
161{
162 struct device *dev = ts->dev;
163 struct max7301_platform_data *pdata;
164 int i, ret;
165
166 pdata = dev_get_platdata(dev);
167
168 mutex_init(&ts->lock);
169 dev_set_drvdata(dev, ts);
170
171 /* Power up the chip and disable IRQ output */
172 ts->write(dev, 0x04, 0x01);
173
174 if (pdata) {
175 ts->input_pullup_active = pdata->input_pullup_active;
176 ts->chip.base = pdata->base;
177 } else {
178 ts->chip.base = -1;
179 }
180 ts->chip.label = dev->driver->name;
181
182 ts->chip.direction_input = max7301_direction_input;
183 ts->chip.get = max7301_get;
184 ts->chip.direction_output = max7301_direction_output;
185 ts->chip.set = max7301_set;
186
187 ts->chip.ngpio = PIN_NUMBER;
188 ts->chip.can_sleep = true;
189 ts->chip.parent = dev;
190 ts->chip.owner = THIS_MODULE;
191
192 /*
193 * initialize pullups according to platform data and cache the
194 * register values for later use.
195 */
196 for (i = 1; i < 8; i++) {
197 int j;
198 /*
199 * initialize port_config with "0xAA", which means
200 * input with internal pullup disabled. This is needed
201 * to avoid writing zeros (in the inner for loop),
202 * which is not allowed according to the datasheet.
203 */
204 ts->port_config[i] = 0xAA;
205 for (j = 0; j < 4; j++) {
206 int offset = (i - 1) * 4 + j;
207 ret = max7301_direction_input(&ts->chip, offset);
208 if (ret)
209 goto exit_destroy;
210 }
211 }
212
213 ret = gpiochip_add_data(&ts->chip, ts);
214 if (!ret)
215 return ret;
216
217exit_destroy:
218 mutex_destroy(&ts->lock);
219 return ret;
220}
221EXPORT_SYMBOL_GPL(__max730x_probe);
222
223void __max730x_remove(struct device *dev)
224{
225 struct max7301 *ts = dev_get_drvdata(dev);
226
227 /* Power down the chip and disable IRQ output */
228 ts->write(dev, 0x04, 0x00);
229 gpiochip_remove(&ts->chip);
230 mutex_destroy(&ts->lock);
231}
232EXPORT_SYMBOL_GPL(__max730x_remove);
233
234MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
235MODULE_LICENSE("GPL v2");
236MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");
1/**
2 * Copyright (C) 2006 Juergen Beisert, Pengutronix
3 * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
4 * Copyright (C) 2009 Wolfram Sang, Pengutronix
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
11 * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
12 * details
13 * Note:
14 * - DIN must be stable at the rising edge of clock.
15 * - when writing:
16 * - always clock in 16 clocks at once
17 * - at DIN: D15 first, D0 last
18 * - D0..D7 = databyte, D8..D14 = commandbyte
19 * - D15 = low -> write command
20 * - when reading
21 * - always clock in 16 clocks at once
22 * - at DIN: D15 first, D0 last
23 * - D0..D7 = dummy, D8..D14 = register address
24 * - D15 = high -> read command
25 * - raise CS and assert it again
26 * - always clock in 16 clocks at once
27 * - at DOUT: D15 first, D0 last
28 * - D0..D7 contains the data from the first cycle
29 *
30 * The driver exports a standard gpiochip interface
31 */
32
33#include <linux/module.h>
34#include <linux/init.h>
35#include <linux/platform_device.h>
36#include <linux/mutex.h>
37#include <linux/spi/max7301.h>
38#include <linux/gpio.h>
39#include <linux/slab.h>
40
41/*
42 * Pin configurations, see MAX7301 datasheet page 6
43 */
44#define PIN_CONFIG_MASK 0x03
45#define PIN_CONFIG_IN_PULLUP 0x03
46#define PIN_CONFIG_IN_WO_PULLUP 0x02
47#define PIN_CONFIG_OUT 0x01
48
49#define PIN_NUMBER 28
50
51static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
52{
53 struct max7301 *ts = gpiochip_get_data(chip);
54 u8 *config;
55 u8 offset_bits, pin_config;
56 int ret;
57
58 /* First 4 pins are unused in the controller */
59 offset += 4;
60 offset_bits = (offset & 3) << 1;
61
62 config = &ts->port_config[offset >> 2];
63
64 if (ts->input_pullup_active & BIT(offset))
65 pin_config = PIN_CONFIG_IN_PULLUP;
66 else
67 pin_config = PIN_CONFIG_IN_WO_PULLUP;
68
69 mutex_lock(&ts->lock);
70
71 *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
72 | (pin_config << offset_bits);
73
74 ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
75
76 mutex_unlock(&ts->lock);
77
78 return ret;
79}
80
81static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
82{
83 if (value) {
84 ts->out_level |= 1 << offset;
85 return ts->write(ts->dev, 0x20 + offset, 0x01);
86 } else {
87 ts->out_level &= ~(1 << offset);
88 return ts->write(ts->dev, 0x20 + offset, 0x00);
89 }
90}
91
92static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
93 int value)
94{
95 struct max7301 *ts = gpiochip_get_data(chip);
96 u8 *config;
97 u8 offset_bits;
98 int ret;
99
100 /* First 4 pins are unused in the controller */
101 offset += 4;
102 offset_bits = (offset & 3) << 1;
103
104 config = &ts->port_config[offset >> 2];
105
106 mutex_lock(&ts->lock);
107
108 *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
109 | (PIN_CONFIG_OUT << offset_bits);
110
111 ret = __max7301_set(ts, offset, value);
112
113 if (!ret)
114 ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
115
116 mutex_unlock(&ts->lock);
117
118 return ret;
119}
120
121static int max7301_get(struct gpio_chip *chip, unsigned offset)
122{
123 struct max7301 *ts = gpiochip_get_data(chip);
124 int config, level = -EINVAL;
125
126 /* First 4 pins are unused in the controller */
127 offset += 4;
128
129 mutex_lock(&ts->lock);
130
131 config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
132 & PIN_CONFIG_MASK;
133
134 switch (config) {
135 case PIN_CONFIG_OUT:
136 /* Output: return cached level */
137 level = !!(ts->out_level & (1 << offset));
138 break;
139 case PIN_CONFIG_IN_WO_PULLUP:
140 case PIN_CONFIG_IN_PULLUP:
141 /* Input: read out */
142 level = ts->read(ts->dev, 0x20 + offset) & 0x01;
143 }
144 mutex_unlock(&ts->lock);
145
146 return level;
147}
148
149static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
150{
151 struct max7301 *ts = gpiochip_get_data(chip);
152
153 /* First 4 pins are unused in the controller */
154 offset += 4;
155
156 mutex_lock(&ts->lock);
157
158 __max7301_set(ts, offset, value);
159
160 mutex_unlock(&ts->lock);
161}
162
163int __max730x_probe(struct max7301 *ts)
164{
165 struct device *dev = ts->dev;
166 struct max7301_platform_data *pdata;
167 int i, ret;
168
169 pdata = dev_get_platdata(dev);
170
171 mutex_init(&ts->lock);
172 dev_set_drvdata(dev, ts);
173
174 /* Power up the chip and disable IRQ output */
175 ts->write(dev, 0x04, 0x01);
176
177 if (pdata) {
178 ts->input_pullup_active = pdata->input_pullup_active;
179 ts->chip.base = pdata->base;
180 } else {
181 ts->chip.base = -1;
182 }
183 ts->chip.label = dev->driver->name;
184
185 ts->chip.direction_input = max7301_direction_input;
186 ts->chip.get = max7301_get;
187 ts->chip.direction_output = max7301_direction_output;
188 ts->chip.set = max7301_set;
189
190 ts->chip.ngpio = PIN_NUMBER;
191 ts->chip.can_sleep = true;
192 ts->chip.parent = dev;
193 ts->chip.owner = THIS_MODULE;
194
195 /*
196 * initialize pullups according to platform data and cache the
197 * register values for later use.
198 */
199 for (i = 1; i < 8; i++) {
200 int j;
201 /*
202 * initialize port_config with "0xAA", which means
203 * input with internal pullup disabled. This is needed
204 * to avoid writing zeros (in the inner for loop),
205 * which is not allowed according to the datasheet.
206 */
207 ts->port_config[i] = 0xAA;
208 for (j = 0; j < 4; j++) {
209 int offset = (i - 1) * 4 + j;
210 ret = max7301_direction_input(&ts->chip, offset);
211 if (ret)
212 goto exit_destroy;
213 }
214 }
215
216 ret = gpiochip_add_data(&ts->chip, ts);
217 if (ret)
218 goto exit_destroy;
219
220 return ret;
221
222exit_destroy:
223 mutex_destroy(&ts->lock);
224 return ret;
225}
226EXPORT_SYMBOL_GPL(__max730x_probe);
227
228int __max730x_remove(struct device *dev)
229{
230 struct max7301 *ts = dev_get_drvdata(dev);
231
232 if (ts == NULL)
233 return -ENODEV;
234
235 /* Power down the chip and disable IRQ output */
236 ts->write(dev, 0x04, 0x00);
237 gpiochip_remove(&ts->chip);
238 mutex_destroy(&ts->lock);
239 return 0;
240}
241EXPORT_SYMBOL_GPL(__max730x_remove);
242
243MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
244MODULE_LICENSE("GPL v2");
245MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");