1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2c103de24SGrant Likely /**
3c103de24SGrant Likely * Copyright (C) 2006 Juergen Beisert, Pengutronix
4c103de24SGrant Likely * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
5c103de24SGrant Likely * Copyright (C) 2009 Wolfram Sang, Pengutronix
6c103de24SGrant Likely *
7c103de24SGrant Likely * The Maxim MAX7300/1 device is an I2C/SPI driven GPIO expander. There are
8c103de24SGrant Likely * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
9c103de24SGrant Likely * details
10c103de24SGrant Likely * Note:
11c103de24SGrant Likely * - DIN must be stable at the rising edge of clock.
12c103de24SGrant Likely * - when writing:
13c103de24SGrant Likely * - always clock in 16 clocks at once
14c103de24SGrant Likely * - at DIN: D15 first, D0 last
15c103de24SGrant Likely * - D0..D7 = databyte, D8..D14 = commandbyte
16c103de24SGrant Likely * - D15 = low -> write command
17c103de24SGrant Likely * - when reading
18c103de24SGrant Likely * - always clock in 16 clocks at once
19c103de24SGrant Likely * - at DIN: D15 first, D0 last
20c103de24SGrant Likely * - D0..D7 = dummy, D8..D14 = register address
21c103de24SGrant Likely * - D15 = high -> read command
22c103de24SGrant Likely * - raise CS and assert it again
23c103de24SGrant Likely * - always clock in 16 clocks at once
24c103de24SGrant Likely * - at DOUT: D15 first, D0 last
25c103de24SGrant Likely * - D0..D7 contains the data from the first cycle
26c103de24SGrant Likely *
27c103de24SGrant Likely * The driver exports a standard gpiochip interface
28c103de24SGrant Likely */
29c103de24SGrant Likely
30c103de24SGrant Likely #include <linux/module.h>
31c103de24SGrant Likely #include <linux/init.h>
32c103de24SGrant Likely #include <linux/platform_device.h>
33c103de24SGrant Likely #include <linux/mutex.h>
34c103de24SGrant Likely #include <linux/spi/max7301.h>
3525424b86SLinus Walleij #include <linux/gpio/driver.h>
36c103de24SGrant Likely #include <linux/slab.h>
37c103de24SGrant Likely
38c103de24SGrant Likely /*
39c103de24SGrant Likely * Pin configurations, see MAX7301 datasheet page 6
40c103de24SGrant Likely */
41c103de24SGrant Likely #define PIN_CONFIG_MASK 0x03
42c103de24SGrant Likely #define PIN_CONFIG_IN_PULLUP 0x03
43c103de24SGrant Likely #define PIN_CONFIG_IN_WO_PULLUP 0x02
44c103de24SGrant Likely #define PIN_CONFIG_OUT 0x01
45c103de24SGrant Likely
46c103de24SGrant Likely #define PIN_NUMBER 28
47c103de24SGrant Likely
max7301_direction_input(struct gpio_chip * chip,unsigned offset)48c103de24SGrant Likely static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
49c103de24SGrant Likely {
5047a3734bSRodrigo Alencar struct max7301 *ts = container_of(chip, struct max7301, chip);
51c103de24SGrant Likely u8 *config;
52c103de24SGrant Likely u8 offset_bits, pin_config;
53c103de24SGrant Likely int ret;
54c103de24SGrant Likely
55c103de24SGrant Likely /* First 4 pins are unused in the controller */
56c103de24SGrant Likely offset += 4;
57c103de24SGrant Likely offset_bits = (offset & 3) << 1;
58c103de24SGrant Likely
59c103de24SGrant Likely config = &ts->port_config[offset >> 2];
60c103de24SGrant Likely
61c103de24SGrant Likely if (ts->input_pullup_active & BIT(offset))
62c103de24SGrant Likely pin_config = PIN_CONFIG_IN_PULLUP;
63c103de24SGrant Likely else
64c103de24SGrant Likely pin_config = PIN_CONFIG_IN_WO_PULLUP;
65c103de24SGrant Likely
66c103de24SGrant Likely mutex_lock(&ts->lock);
67c103de24SGrant Likely
68c103de24SGrant Likely *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
69c103de24SGrant Likely | (pin_config << offset_bits);
70c103de24SGrant Likely
71c103de24SGrant Likely ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
72c103de24SGrant Likely
73c103de24SGrant Likely mutex_unlock(&ts->lock);
74c103de24SGrant Likely
75c103de24SGrant Likely return ret;
76c103de24SGrant Likely }
77c103de24SGrant Likely
__max7301_set(struct max7301 * ts,unsigned offset,int value)78c103de24SGrant Likely static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
79c103de24SGrant Likely {
80c103de24SGrant Likely if (value) {
81c103de24SGrant Likely ts->out_level |= 1 << offset;
82c103de24SGrant Likely return ts->write(ts->dev, 0x20 + offset, 0x01);
83c103de24SGrant Likely } else {
84c103de24SGrant Likely ts->out_level &= ~(1 << offset);
85c103de24SGrant Likely return ts->write(ts->dev, 0x20 + offset, 0x00);
86c103de24SGrant Likely }
87c103de24SGrant Likely }
88c103de24SGrant Likely
max7301_direction_output(struct gpio_chip * chip,unsigned offset,int value)89c103de24SGrant Likely static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
90c103de24SGrant Likely int value)
91c103de24SGrant Likely {
9247a3734bSRodrigo Alencar struct max7301 *ts = container_of(chip, struct max7301, chip);
93c103de24SGrant Likely u8 *config;
94c103de24SGrant Likely u8 offset_bits;
95c103de24SGrant Likely int ret;
96c103de24SGrant Likely
97c103de24SGrant Likely /* First 4 pins are unused in the controller */
98c103de24SGrant Likely offset += 4;
99c103de24SGrant Likely offset_bits = (offset & 3) << 1;
100c103de24SGrant Likely
101c103de24SGrant Likely config = &ts->port_config[offset >> 2];
102c103de24SGrant Likely
103c103de24SGrant Likely mutex_lock(&ts->lock);
104c103de24SGrant Likely
105c103de24SGrant Likely *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
106c103de24SGrant Likely | (PIN_CONFIG_OUT << offset_bits);
107c103de24SGrant Likely
108c103de24SGrant Likely ret = __max7301_set(ts, offset, value);
109c103de24SGrant Likely
110c103de24SGrant Likely if (!ret)
111c103de24SGrant Likely ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
112c103de24SGrant Likely
113c103de24SGrant Likely mutex_unlock(&ts->lock);
114c103de24SGrant Likely
115c103de24SGrant Likely return ret;
116c103de24SGrant Likely }
117c103de24SGrant Likely
max7301_get(struct gpio_chip * chip,unsigned offset)118c103de24SGrant Likely static int max7301_get(struct gpio_chip *chip, unsigned offset)
119c103de24SGrant Likely {
1205e45e019SLinus Walleij struct max7301 *ts = gpiochip_get_data(chip);
121c103de24SGrant Likely int config, level = -EINVAL;
122c103de24SGrant Likely
123c103de24SGrant Likely /* First 4 pins are unused in the controller */
124c103de24SGrant Likely offset += 4;
125c103de24SGrant Likely
126c103de24SGrant Likely mutex_lock(&ts->lock);
127c103de24SGrant Likely
128c103de24SGrant Likely config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
129c103de24SGrant Likely & PIN_CONFIG_MASK;
130c103de24SGrant Likely
131c103de24SGrant Likely switch (config) {
132c103de24SGrant Likely case PIN_CONFIG_OUT:
133c103de24SGrant Likely /* Output: return cached level */
134c103de24SGrant Likely level = !!(ts->out_level & (1 << offset));
135c103de24SGrant Likely break;
136c103de24SGrant Likely case PIN_CONFIG_IN_WO_PULLUP:
137c103de24SGrant Likely case PIN_CONFIG_IN_PULLUP:
138c103de24SGrant Likely /* Input: read out */
139c103de24SGrant Likely level = ts->read(ts->dev, 0x20 + offset) & 0x01;
140c103de24SGrant Likely }
141c103de24SGrant Likely mutex_unlock(&ts->lock);
142c103de24SGrant Likely
143c103de24SGrant Likely return level;
144c103de24SGrant Likely }
145c103de24SGrant Likely
max7301_set(struct gpio_chip * chip,unsigned offset,int value)146c103de24SGrant Likely static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
147c103de24SGrant Likely {
1485e45e019SLinus Walleij struct max7301 *ts = gpiochip_get_data(chip);
149c103de24SGrant Likely
150c103de24SGrant Likely /* First 4 pins are unused in the controller */
151c103de24SGrant Likely offset += 4;
152c103de24SGrant Likely
153c103de24SGrant Likely mutex_lock(&ts->lock);
154c103de24SGrant Likely
155c103de24SGrant Likely __max7301_set(ts, offset, value);
156c103de24SGrant Likely
157c103de24SGrant Likely mutex_unlock(&ts->lock);
158c103de24SGrant Likely }
159c103de24SGrant Likely
__max730x_probe(struct max7301 * ts)1603836309dSBill Pemberton int __max730x_probe(struct max7301 *ts)
161c103de24SGrant Likely {
162c103de24SGrant Likely struct device *dev = ts->dev;
163c103de24SGrant Likely struct max7301_platform_data *pdata;
164c103de24SGrant Likely int i, ret;
165c103de24SGrant Likely
166e56aee18SJingoo Han pdata = dev_get_platdata(dev);
167c103de24SGrant Likely
168c103de24SGrant Likely mutex_init(&ts->lock);
169c103de24SGrant Likely dev_set_drvdata(dev, ts);
170c103de24SGrant Likely
171c103de24SGrant Likely /* Power up the chip and disable IRQ output */
172c103de24SGrant Likely ts->write(dev, 0x04, 0x01);
173c103de24SGrant Likely
1748754fccbSRoland Stigge if (pdata) {
175c103de24SGrant Likely ts->input_pullup_active = pdata->input_pullup_active;
1768754fccbSRoland Stigge ts->chip.base = pdata->base;
1778754fccbSRoland Stigge } else {
1788754fccbSRoland Stigge ts->chip.base = -1;
1798754fccbSRoland Stigge }
180c103de24SGrant Likely ts->chip.label = dev->driver->name;
181c103de24SGrant Likely
182c103de24SGrant Likely ts->chip.direction_input = max7301_direction_input;
183c103de24SGrant Likely ts->chip.get = max7301_get;
184c103de24SGrant Likely ts->chip.direction_output = max7301_direction_output;
185c103de24SGrant Likely ts->chip.set = max7301_set;
186c103de24SGrant Likely
187c103de24SGrant Likely ts->chip.ngpio = PIN_NUMBER;
1889fb1f39eSLinus Walleij ts->chip.can_sleep = true;
18958383c78SLinus Walleij ts->chip.parent = dev;
190c103de24SGrant Likely ts->chip.owner = THIS_MODULE;
191c103de24SGrant Likely
192c103de24SGrant Likely /*
193c103de24SGrant Likely * initialize pullups according to platform data and cache the
194c103de24SGrant Likely * register values for later use.
195c103de24SGrant Likely */
196c103de24SGrant Likely for (i = 1; i < 8; i++) {
197c103de24SGrant Likely int j;
198c103de24SGrant Likely /*
199c103de24SGrant Likely * initialize port_config with "0xAA", which means
200c103de24SGrant Likely * input with internal pullup disabled. This is needed
201c103de24SGrant Likely * to avoid writing zeros (in the inner for loop),
202c103de24SGrant Likely * which is not allowed according to the datasheet.
203c103de24SGrant Likely */
204c103de24SGrant Likely ts->port_config[i] = 0xAA;
205c103de24SGrant Likely for (j = 0; j < 4; j++) {
206c103de24SGrant Likely int offset = (i - 1) * 4 + j;
207c103de24SGrant Likely ret = max7301_direction_input(&ts->chip, offset);
208c103de24SGrant Likely if (ret)
209c103de24SGrant Likely goto exit_destroy;
210c103de24SGrant Likely }
211c103de24SGrant Likely }
212c103de24SGrant Likely
21347a3734bSRodrigo Alencar ret = gpiochip_add_data(&ts->chip, ts);
21447a3734bSRodrigo Alencar if (!ret)
215c103de24SGrant Likely return ret;
216c103de24SGrant Likely
217c103de24SGrant Likely exit_destroy:
218c103de24SGrant Likely mutex_destroy(&ts->lock);
219c103de24SGrant Likely return ret;
220c103de24SGrant Likely }
221c103de24SGrant Likely EXPORT_SYMBOL_GPL(__max730x_probe);
222c103de24SGrant Likely
__max730x_remove(struct device * dev)223*06de2cd7SUwe Kleine-König void __max730x_remove(struct device *dev)
224c103de24SGrant Likely {
225c103de24SGrant Likely struct max7301 *ts = dev_get_drvdata(dev);
226c103de24SGrant Likely
227c103de24SGrant Likely /* Power down the chip and disable IRQ output */
228c103de24SGrant Likely ts->write(dev, 0x04, 0x00);
2299f5132aeSabdoulaye berthe gpiochip_remove(&ts->chip);
230c103de24SGrant Likely mutex_destroy(&ts->lock);
231c103de24SGrant Likely }
232c103de24SGrant Likely EXPORT_SYMBOL_GPL(__max730x_remove);
233c103de24SGrant Likely
234c103de24SGrant Likely MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
235c103de24SGrant Likely MODULE_LICENSE("GPL v2");
236c103de24SGrant Likely MODULE_DESCRIPTION("MAX730x GPIO-Expanders, generic parts");
237