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97a445da WBG |
1 | /* |
2 | * DAC driver for the Apex Embedded Systems STX104 | |
3 | * Copyright (C) 2016 William Breathitt Gray | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License, version 2, as | |
7 | * published by the Free Software Foundation. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, but | |
10 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * General Public License for more details. | |
13 | */ | |
14 | #include <linux/bitops.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/errno.h> | |
765550e4 | 17 | #include <linux/gpio/driver.h> |
97a445da WBG |
18 | #include <linux/iio/iio.h> |
19 | #include <linux/iio/types.h> | |
20 | #include <linux/io.h> | |
21 | #include <linux/ioport.h> | |
22 | #include <linux/isa.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/moduleparam.h> | |
765550e4 | 25 | #include <linux/spinlock.h> |
97a445da WBG |
26 | |
27 | #define STX104_NUM_CHAN 2 | |
28 | ||
29 | #define STX104_CHAN(chan) { \ | |
30 | .type = IIO_VOLTAGE, \ | |
31 | .channel = chan, \ | |
32 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
33 | .indexed = 1, \ | |
34 | .output = 1 \ | |
35 | } | |
36 | ||
37 | #define STX104_EXTENT 16 | |
97a445da | 38 | |
9c2cfc19 WBG |
39 | static unsigned int base[max_num_isa_dev(STX104_EXTENT)]; |
40 | static unsigned int num_stx104; | |
97a445da WBG |
41 | module_param_array(base, uint, &num_stx104, 0); |
42 | MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses"); | |
43 | ||
44 | /** | |
45 | * struct stx104_iio - IIO device private data structure | |
46 | * @chan_out_states: channels' output states | |
47 | * @base: base port address of the IIO device | |
48 | */ | |
49 | struct stx104_iio { | |
50 | unsigned chan_out_states[STX104_NUM_CHAN]; | |
51 | unsigned base; | |
52 | }; | |
53 | ||
765550e4 WBG |
54 | /** |
55 | * struct stx104_gpio - GPIO device private data structure | |
56 | * @chip: instance of the gpio_chip | |
57 | * @lock: synchronization lock to prevent I/O race conditions | |
58 | * @base: base port address of the GPIO device | |
59 | * @out_state: output bits state | |
60 | */ | |
61 | struct stx104_gpio { | |
62 | struct gpio_chip chip; | |
63 | spinlock_t lock; | |
64 | unsigned int base; | |
65 | unsigned int out_state; | |
66 | }; | |
67 | ||
97a445da WBG |
68 | static int stx104_read_raw(struct iio_dev *indio_dev, |
69 | struct iio_chan_spec const *chan, int *val, int *val2, long mask) | |
70 | { | |
71 | struct stx104_iio *const priv = iio_priv(indio_dev); | |
72 | ||
73 | if (mask != IIO_CHAN_INFO_RAW) | |
74 | return -EINVAL; | |
75 | ||
76 | *val = priv->chan_out_states[chan->channel]; | |
77 | ||
78 | return IIO_VAL_INT; | |
79 | } | |
80 | ||
81 | static int stx104_write_raw(struct iio_dev *indio_dev, | |
82 | struct iio_chan_spec const *chan, int val, int val2, long mask) | |
83 | { | |
84 | struct stx104_iio *const priv = iio_priv(indio_dev); | |
85 | const unsigned chan_addr_offset = 2 * chan->channel; | |
86 | ||
87 | if (mask != IIO_CHAN_INFO_RAW) | |
88 | return -EINVAL; | |
89 | ||
90 | priv->chan_out_states[chan->channel] = val; | |
91 | outw(val, priv->base + 4 + chan_addr_offset); | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | static const struct iio_info stx104_info = { | |
97 | .driver_module = THIS_MODULE, | |
98 | .read_raw = stx104_read_raw, | |
99 | .write_raw = stx104_write_raw | |
100 | }; | |
101 | ||
102 | static const struct iio_chan_spec stx104_channels[STX104_NUM_CHAN] = { | |
103 | STX104_CHAN(0), | |
104 | STX104_CHAN(1) | |
105 | }; | |
106 | ||
765550e4 WBG |
107 | static int stx104_gpio_get_direction(struct gpio_chip *chip, |
108 | unsigned int offset) | |
109 | { | |
110 | if (offset < 4) | |
111 | return 1; | |
112 | ||
113 | return 0; | |
114 | } | |
115 | ||
116 | static int stx104_gpio_direction_input(struct gpio_chip *chip, | |
117 | unsigned int offset) | |
118 | { | |
119 | if (offset >= 4) | |
120 | return -EINVAL; | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int stx104_gpio_direction_output(struct gpio_chip *chip, | |
126 | unsigned int offset, int value) | |
127 | { | |
128 | if (offset < 4) | |
129 | return -EINVAL; | |
130 | ||
131 | chip->set(chip, offset, value); | |
132 | return 0; | |
133 | } | |
134 | ||
135 | static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset) | |
136 | { | |
137 | struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip); | |
138 | ||
139 | if (offset >= 4) | |
140 | return -EINVAL; | |
141 | ||
142 | return !!(inb(stx104gpio->base) & BIT(offset)); | |
143 | } | |
144 | ||
145 | static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset, | |
146 | int value) | |
147 | { | |
148 | struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip); | |
149 | const unsigned int mask = BIT(offset) >> 4; | |
150 | unsigned long flags; | |
151 | ||
152 | if (offset < 4) | |
153 | return; | |
154 | ||
155 | spin_lock_irqsave(&stx104gpio->lock, flags); | |
156 | ||
157 | if (value) | |
158 | stx104gpio->out_state |= mask; | |
159 | else | |
160 | stx104gpio->out_state &= ~mask; | |
161 | ||
162 | outb(stx104gpio->out_state, stx104gpio->base); | |
163 | ||
164 | spin_unlock_irqrestore(&stx104gpio->lock, flags); | |
165 | } | |
166 | ||
97a445da WBG |
167 | static int stx104_probe(struct device *dev, unsigned int id) |
168 | { | |
169 | struct iio_dev *indio_dev; | |
170 | struct stx104_iio *priv; | |
765550e4 WBG |
171 | struct stx104_gpio *stx104gpio; |
172 | int err; | |
97a445da WBG |
173 | |
174 | indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); | |
175 | if (!indio_dev) | |
176 | return -ENOMEM; | |
177 | ||
765550e4 WBG |
178 | stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL); |
179 | if (!stx104gpio) | |
180 | return -ENOMEM; | |
181 | ||
97a445da WBG |
182 | if (!devm_request_region(dev, base[id], STX104_EXTENT, |
183 | dev_name(dev))) { | |
184 | dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", | |
185 | base[id], base[id] + STX104_EXTENT); | |
186 | return -EBUSY; | |
187 | } | |
188 | ||
189 | indio_dev->info = &stx104_info; | |
190 | indio_dev->modes = INDIO_DIRECT_MODE; | |
191 | indio_dev->channels = stx104_channels; | |
192 | indio_dev->num_channels = STX104_NUM_CHAN; | |
193 | indio_dev->name = dev_name(dev); | |
194 | ||
195 | priv = iio_priv(indio_dev); | |
196 | priv->base = base[id]; | |
197 | ||
198 | /* initialize DAC output to 0V */ | |
199 | outw(0, base[id] + 4); | |
200 | outw(0, base[id] + 6); | |
201 | ||
765550e4 WBG |
202 | err = devm_iio_device_register(dev, indio_dev); |
203 | if (err) { | |
204 | dev_err(dev, "IIO device registering failed (%d)\n", err); | |
205 | return err; | |
206 | } | |
207 | ||
208 | stx104gpio->chip.label = dev_name(dev); | |
209 | stx104gpio->chip.parent = dev; | |
210 | stx104gpio->chip.owner = THIS_MODULE; | |
211 | stx104gpio->chip.base = -1; | |
212 | stx104gpio->chip.ngpio = 8; | |
213 | stx104gpio->chip.get_direction = stx104_gpio_get_direction; | |
214 | stx104gpio->chip.direction_input = stx104_gpio_direction_input; | |
215 | stx104gpio->chip.direction_output = stx104_gpio_direction_output; | |
216 | stx104gpio->chip.get = stx104_gpio_get; | |
217 | stx104gpio->chip.set = stx104_gpio_set; | |
218 | stx104gpio->base = base[id] + 3; | |
219 | stx104gpio->out_state = 0x0; | |
220 | ||
221 | spin_lock_init(&stx104gpio->lock); | |
222 | ||
223 | dev_set_drvdata(dev, stx104gpio); | |
224 | ||
225 | err = gpiochip_add_data(&stx104gpio->chip, stx104gpio); | |
226 | if (err) { | |
227 | dev_err(dev, "GPIO registering failed (%d)\n", err); | |
228 | return err; | |
229 | } | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | static int stx104_remove(struct device *dev, unsigned int id) | |
235 | { | |
236 | struct stx104_gpio *const stx104gpio = dev_get_drvdata(dev); | |
237 | ||
238 | gpiochip_remove(&stx104gpio->chip); | |
239 | ||
240 | return 0; | |
97a445da WBG |
241 | } |
242 | ||
243 | static struct isa_driver stx104_driver = { | |
244 | .probe = stx104_probe, | |
245 | .driver = { | |
246 | .name = "stx104" | |
765550e4 WBG |
247 | }, |
248 | .remove = stx104_remove | |
97a445da WBG |
249 | }; |
250 | ||
9c2cfc19 | 251 | module_isa_driver(stx104_driver, num_stx104); |
97a445da WBG |
252 | |
253 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); | |
254 | MODULE_DESCRIPTION("Apex Embedded Systems STX104 DAC driver"); | |
255 | MODULE_LICENSE("GPL v2"); |