diff options
author | Andrea Bastoni <bastoni@cs.unc.edu> | 2010-05-30 19:16:45 -0400 |
---|---|---|
committer | Andrea Bastoni <bastoni@cs.unc.edu> | 2010-05-30 19:16:45 -0400 |
commit | ada47b5fe13d89735805b566185f4885f5a3f750 (patch) | |
tree | 644b88f8a71896307d71438e9b3af49126ffb22b /drivers/gpio/max7301.c | |
parent | 43e98717ad40a4ae64545b5ba047c7b86aa44f4f (diff) | |
parent | 3280f21d43ee541f97f8cda5792150d2dbec20d5 (diff) |
Merge branch 'wip-2.6.34' into old-private-masterarchived-private-master
Diffstat (limited to 'drivers/gpio/max7301.c')
-rw-r--r-- | drivers/gpio/max7301.c | 294 |
1 files changed, 35 insertions, 259 deletions
diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c index 480956f1ca50..92a100ddef6b 100644 --- a/drivers/gpio/max7301.c +++ b/drivers/gpio/max7301.c | |||
@@ -1,98 +1,42 @@ | |||
1 | /** | 1 | /* |
2 | * drivers/gpio/max7301.c | 2 | * drivers/gpio/max7301.c |
3 | * | 3 | * |
4 | * Copyright (C) 2006 Juergen Beisert, Pengutronix | 4 | * Copyright (C) 2006 Juergen Beisert, Pengutronix |
5 | * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix | 5 | * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix |
6 | * Copyright (C) 2009 Wolfram Sang, Pengutronix | ||
6 | * | 7 | * |
7 | * This program is free software; you can redistribute it and/or modify | 8 | * This program is free software; you can redistribute it and/or modify |
8 | * it under the terms of the GNU General Public License version 2 as | 9 | * it under the terms of the GNU General Public License version 2 as |
9 | * published by the Free Software Foundation. | 10 | * published by the Free Software Foundation. |
10 | * | 11 | * |
11 | * The Maxim's MAX7301 device is an SPI driven GPIO expander. There are | 12 | * Check max730x.c for further details. |
12 | * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more | ||
13 | * details | ||
14 | * Note: | ||
15 | * - DIN must be stable at the rising edge of clock. | ||
16 | * - when writing: | ||
17 | * - always clock in 16 clocks at once | ||
18 | * - at DIN: D15 first, D0 last | ||
19 | * - D0..D7 = databyte, D8..D14 = commandbyte | ||
20 | * - D15 = low -> write command | ||
21 | * - when reading | ||
22 | * - always clock in 16 clocks at once | ||
23 | * - at DIN: D15 first, D0 last | ||
24 | * - D0..D7 = dummy, D8..D14 = register address | ||
25 | * - D15 = high -> read command | ||
26 | * - raise CS and assert it again | ||
27 | * - always clock in 16 clocks at once | ||
28 | * - at DOUT: D15 first, D0 last | ||
29 | * - D0..D7 contains the data from the first cycle | ||
30 | * | ||
31 | * The driver exports a standard gpiochip interface | ||
32 | */ | 13 | */ |
33 | 14 | ||
15 | #include <linux/module.h> | ||
34 | #include <linux/init.h> | 16 | #include <linux/init.h> |
35 | #include <linux/platform_device.h> | 17 | #include <linux/platform_device.h> |
36 | #include <linux/mutex.h> | 18 | #include <linux/mutex.h> |
19 | #include <linux/slab.h> | ||
37 | #include <linux/spi/spi.h> | 20 | #include <linux/spi/spi.h> |
38 | #include <linux/spi/max7301.h> | 21 | #include <linux/spi/max7301.h> |
39 | #include <linux/gpio.h> | ||
40 | |||
41 | #define DRIVER_NAME "max7301" | ||
42 | |||
43 | /* | ||
44 | * Pin configurations, see MAX7301 datasheet page 6 | ||
45 | */ | ||
46 | #define PIN_CONFIG_MASK 0x03 | ||
47 | #define PIN_CONFIG_IN_PULLUP 0x03 | ||
48 | #define PIN_CONFIG_IN_WO_PULLUP 0x02 | ||
49 | #define PIN_CONFIG_OUT 0x01 | ||
50 | |||
51 | #define PIN_NUMBER 28 | ||
52 | |||
53 | |||
54 | /* | ||
55 | * Some registers must be read back to modify. | ||
56 | * To save time we cache them here in memory | ||
57 | */ | ||
58 | struct max7301 { | ||
59 | struct mutex lock; | ||
60 | u8 port_config[8]; /* field 0 is unused */ | ||
61 | u32 out_level; /* cached output levels */ | ||
62 | struct gpio_chip chip; | ||
63 | struct spi_device *spi; | ||
64 | }; | ||
65 | 22 | ||
66 | /** | 23 | /* A write to the MAX7301 means one message with one transfer */ |
67 | * max7301_write - Write a new register content | 24 | static int max7301_spi_write(struct device *dev, unsigned int reg, |
68 | * @spi: The SPI device | 25 | unsigned int val) |
69 | * @reg: Register offset | ||
70 | * @val: Value to write | ||
71 | * | ||
72 | * A write to the MAX7301 means one message with one transfer | ||
73 | * | ||
74 | * Returns 0 if successful or a negative value on error | ||
75 | */ | ||
76 | static int max7301_write(struct spi_device *spi, unsigned int reg, unsigned int val) | ||
77 | { | 26 | { |
27 | struct spi_device *spi = to_spi_device(dev); | ||
78 | u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); | 28 | u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); |
29 | |||
79 | return spi_write(spi, (const u8 *)&word, sizeof(word)); | 30 | return spi_write(spi, (const u8 *)&word, sizeof(word)); |
80 | } | 31 | } |
81 | 32 | ||
82 | /** | 33 | /* A read from the MAX7301 means two transfers; here, one message each */ |
83 | * max7301_read - Read back register content | 34 | |
84 | * @spi: The SPI device | 35 | static int max7301_spi_read(struct device *dev, unsigned int reg) |
85 | * @reg: Register offset | ||
86 | * | ||
87 | * A read from the MAX7301 means two transfers; here, one message each | ||
88 | * | ||
89 | * Returns positive 8 bit value from device if successful or a | ||
90 | * negative value on error | ||
91 | */ | ||
92 | static int max7301_read(struct spi_device *spi, unsigned int reg) | ||
93 | { | 36 | { |
94 | int ret; | 37 | int ret; |
95 | u16 word; | 38 | u16 word; |
39 | struct spi_device *spi = to_spi_device(dev); | ||
96 | 40 | ||
97 | word = 0x8000 | (reg << 8); | 41 | word = 0x8000 | (reg << 8); |
98 | ret = spi_write(spi, (const u8 *)&word, sizeof(word)); | 42 | ret = spi_write(spi, (const u8 *)&word, sizeof(word)); |
@@ -108,125 +52,13 @@ static int max7301_read(struct spi_device *spi, unsigned int reg) | |||
108 | return word & 0xff; | 52 | return word & 0xff; |
109 | } | 53 | } |
110 | 54 | ||
111 | static int max7301_direction_input(struct gpio_chip *chip, unsigned offset) | ||
112 | { | ||
113 | struct max7301 *ts = container_of(chip, struct max7301, chip); | ||
114 | u8 *config; | ||
115 | int ret; | ||
116 | |||
117 | /* First 4 pins are unused in the controller */ | ||
118 | offset += 4; | ||
119 | |||
120 | config = &ts->port_config[offset >> 2]; | ||
121 | |||
122 | mutex_lock(&ts->lock); | ||
123 | |||
124 | /* Standard GPIO API doesn't support pull-ups, has to be extended. | ||
125 | * Hard-coding no pollup for now. */ | ||
126 | *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3)); | ||
127 | |||
128 | ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config); | ||
129 | |||
130 | mutex_unlock(&ts->lock); | ||
131 | |||
132 | return ret; | ||
133 | } | ||
134 | |||
135 | static int __max7301_set(struct max7301 *ts, unsigned offset, int value) | ||
136 | { | ||
137 | if (value) { | ||
138 | ts->out_level |= 1 << offset; | ||
139 | return max7301_write(ts->spi, 0x20 + offset, 0x01); | ||
140 | } else { | ||
141 | ts->out_level &= ~(1 << offset); | ||
142 | return max7301_write(ts->spi, 0x20 + offset, 0x00); | ||
143 | } | ||
144 | } | ||
145 | |||
146 | static int max7301_direction_output(struct gpio_chip *chip, unsigned offset, | ||
147 | int value) | ||
148 | { | ||
149 | struct max7301 *ts = container_of(chip, struct max7301, chip); | ||
150 | u8 *config; | ||
151 | int ret; | ||
152 | |||
153 | /* First 4 pins are unused in the controller */ | ||
154 | offset += 4; | ||
155 | |||
156 | config = &ts->port_config[offset >> 2]; | ||
157 | |||
158 | mutex_lock(&ts->lock); | ||
159 | |||
160 | *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3)); | ||
161 | |||
162 | ret = __max7301_set(ts, offset, value); | ||
163 | |||
164 | if (!ret) | ||
165 | ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config); | ||
166 | |||
167 | mutex_unlock(&ts->lock); | ||
168 | |||
169 | return ret; | ||
170 | } | ||
171 | |||
172 | static int max7301_get(struct gpio_chip *chip, unsigned offset) | ||
173 | { | ||
174 | struct max7301 *ts = container_of(chip, struct max7301, chip); | ||
175 | int config, level = -EINVAL; | ||
176 | |||
177 | /* First 4 pins are unused in the controller */ | ||
178 | offset += 4; | ||
179 | |||
180 | mutex_lock(&ts->lock); | ||
181 | |||
182 | config = (ts->port_config[offset >> 2] >> ((offset & 3) * 2)) & 3; | ||
183 | |||
184 | switch (config) { | ||
185 | case 1: | ||
186 | /* Output: return cached level */ | ||
187 | level = !!(ts->out_level & (1 << offset)); | ||
188 | break; | ||
189 | case 2: | ||
190 | case 3: | ||
191 | /* Input: read out */ | ||
192 | level = max7301_read(ts->spi, 0x20 + offset) & 0x01; | ||
193 | } | ||
194 | mutex_unlock(&ts->lock); | ||
195 | |||
196 | return level; | ||
197 | } | ||
198 | |||
199 | static void max7301_set(struct gpio_chip *chip, unsigned offset, int value) | ||
200 | { | ||
201 | struct max7301 *ts = container_of(chip, struct max7301, chip); | ||
202 | |||
203 | /* First 4 pins are unused in the controller */ | ||
204 | offset += 4; | ||
205 | |||
206 | mutex_lock(&ts->lock); | ||
207 | |||
208 | __max7301_set(ts, offset, value); | ||
209 | |||
210 | mutex_unlock(&ts->lock); | ||
211 | } | ||
212 | |||
213 | static int __devinit max7301_probe(struct spi_device *spi) | 55 | static int __devinit max7301_probe(struct spi_device *spi) |
214 | { | 56 | { |
215 | struct max7301 *ts; | 57 | struct max7301 *ts; |
216 | struct max7301_platform_data *pdata; | 58 | int ret; |
217 | int i, ret; | ||
218 | |||
219 | pdata = spi->dev.platform_data; | ||
220 | if (!pdata || !pdata->base) { | ||
221 | dev_dbg(&spi->dev, "incorrect or missing platform data\n"); | ||
222 | return -EINVAL; | ||
223 | } | ||
224 | 59 | ||
225 | /* | 60 | /* bits_per_word cannot be configured in platform data */ |
226 | * bits_per_word cannot be configured in platform data | ||
227 | */ | ||
228 | spi->bits_per_word = 16; | 61 | spi->bits_per_word = 16; |
229 | |||
230 | ret = spi_setup(spi); | 62 | ret = spi_setup(spi); |
231 | if (ret < 0) | 63 | if (ret < 0) |
232 | return ret; | 64 | return ret; |
@@ -235,90 +67,35 @@ static int __devinit max7301_probe(struct spi_device *spi) | |||
235 | if (!ts) | 67 | if (!ts) |
236 | return -ENOMEM; | 68 | return -ENOMEM; |
237 | 69 | ||
238 | mutex_init(&ts->lock); | 70 | ts->read = max7301_spi_read; |
239 | 71 | ts->write = max7301_spi_write; | |
240 | dev_set_drvdata(&spi->dev, ts); | 72 | ts->dev = &spi->dev; |
241 | 73 | ||
242 | /* Power up the chip and disable IRQ output */ | 74 | ret = __max730x_probe(ts); |
243 | max7301_write(spi, 0x04, 0x01); | ||
244 | |||
245 | ts->spi = spi; | ||
246 | |||
247 | ts->chip.label = DRIVER_NAME, | ||
248 | |||
249 | ts->chip.direction_input = max7301_direction_input; | ||
250 | ts->chip.get = max7301_get; | ||
251 | ts->chip.direction_output = max7301_direction_output; | ||
252 | ts->chip.set = max7301_set; | ||
253 | |||
254 | ts->chip.base = pdata->base; | ||
255 | ts->chip.ngpio = PIN_NUMBER; | ||
256 | ts->chip.can_sleep = 1; | ||
257 | ts->chip.dev = &spi->dev; | ||
258 | ts->chip.owner = THIS_MODULE; | ||
259 | |||
260 | /* | ||
261 | * tristate all pins in hardware and cache the | ||
262 | * register values for later use. | ||
263 | */ | ||
264 | for (i = 1; i < 8; i++) { | ||
265 | int j; | ||
266 | /* 0xAA means input with internal pullup disabled */ | ||
267 | max7301_write(spi, 0x08 + i, 0xAA); | ||
268 | ts->port_config[i] = 0xAA; | ||
269 | for (j = 0; j < 4; j++) { | ||
270 | int offset = (i - 1) * 4 + j; | ||
271 | ret = max7301_direction_input(&ts->chip, offset); | ||
272 | if (ret) | ||
273 | goto exit_destroy; | ||
274 | } | ||
275 | } | ||
276 | |||
277 | ret = gpiochip_add(&ts->chip); | ||
278 | if (ret) | 75 | if (ret) |
279 | goto exit_destroy; | 76 | kfree(ts); |
280 | |||
281 | return ret; | ||
282 | |||
283 | exit_destroy: | ||
284 | dev_set_drvdata(&spi->dev, NULL); | ||
285 | mutex_destroy(&ts->lock); | ||
286 | kfree(ts); | ||
287 | return ret; | 77 | return ret; |
288 | } | 78 | } |
289 | 79 | ||
290 | static int __devexit max7301_remove(struct spi_device *spi) | 80 | static int __devexit max7301_remove(struct spi_device *spi) |
291 | { | 81 | { |
292 | struct max7301 *ts; | 82 | return __max730x_remove(&spi->dev); |
293 | int ret; | ||
294 | |||
295 | ts = dev_get_drvdata(&spi->dev); | ||
296 | if (ts == NULL) | ||
297 | return -ENODEV; | ||
298 | |||
299 | dev_set_drvdata(&spi->dev, NULL); | ||
300 | |||
301 | /* Power down the chip and disable IRQ output */ | ||
302 | max7301_write(spi, 0x04, 0x00); | ||
303 | |||
304 | ret = gpiochip_remove(&ts->chip); | ||
305 | if (!ret) { | ||
306 | mutex_destroy(&ts->lock); | ||
307 | kfree(ts); | ||
308 | } else | ||
309 | dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n", | ||
310 | ret); | ||
311 | |||
312 | return ret; | ||
313 | } | 83 | } |
314 | 84 | ||
85 | static const struct spi_device_id max7301_id[] = { | ||
86 | { "max7301", 0 }, | ||
87 | { } | ||
88 | }; | ||
89 | MODULE_DEVICE_TABLE(spi, max7301_id); | ||
90 | |||
315 | static struct spi_driver max7301_driver = { | 91 | static struct spi_driver max7301_driver = { |
316 | .driver = { | 92 | .driver = { |
317 | .name = DRIVER_NAME, | 93 | .name = "max7301", |
318 | .owner = THIS_MODULE, | 94 | .owner = THIS_MODULE, |
319 | }, | 95 | }, |
320 | .probe = max7301_probe, | 96 | .probe = max7301_probe, |
321 | .remove = __devexit_p(max7301_remove), | 97 | .remove = __devexit_p(max7301_remove), |
98 | .id_table = max7301_id, | ||
322 | }; | 99 | }; |
323 | 100 | ||
324 | static int __init max7301_init(void) | 101 | static int __init max7301_init(void) |
@@ -336,7 +113,6 @@ static void __exit max7301_exit(void) | |||
336 | } | 113 | } |
337 | module_exit(max7301_exit); | 114 | module_exit(max7301_exit); |
338 | 115 | ||
339 | MODULE_AUTHOR("Juergen Beisert"); | 116 | MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); |
340 | MODULE_LICENSE("GPL v2"); | 117 | MODULE_LICENSE("GPL v2"); |
341 | MODULE_DESCRIPTION("MAX7301 SPI based GPIO-Expander"); | 118 | MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |
342 | MODULE_ALIAS("spi:" DRIVER_NAME); | ||