1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * comedi_8255.c |
4 | * Generic 8255 digital I/O support |
5 | * |
6 | * Split from the Comedi "8255" driver module. |
7 | * |
8 | * COMEDI - Linux Control and Measurement Device Interface |
9 | * Copyright (C) 1998 David A. Schleef <ds@schleef.org> |
10 | */ |
11 | |
12 | /* |
13 | * Module: comedi_8255 |
14 | * Description: Generic 8255 support |
15 | * Author: ds |
16 | * Updated: Fri, 22 May 2015 12:14:17 +0000 |
17 | * Status: works |
18 | * |
19 | * This module is not used directly by end-users. Rather, it is used by |
20 | * other drivers to provide support for an 8255 "Programmable Peripheral |
21 | * Interface" (PPI) chip. |
22 | * |
23 | * The classic in digital I/O. The 8255 appears in Comedi as a single |
24 | * digital I/O subdevice with 24 channels. The channel 0 corresponds to |
25 | * the 8255's port A, bit 0; channel 23 corresponds to port C, bit 7. |
26 | * Direction configuration is done in blocks, with channels 0-7, 8-15, |
27 | * 16-19, and 20-23 making up the 4 blocks. The only 8255 mode |
28 | * supported is mode 0. |
29 | */ |
30 | |
31 | #include <linux/module.h> |
32 | #include <linux/comedi/comedidev.h> |
33 | #include <linux/comedi/comedi_8255.h> |
34 | |
35 | struct subdev_8255_private { |
36 | unsigned long context; |
37 | int (*io)(struct comedi_device *dev, int dir, int port, int data, |
38 | unsigned long context); |
39 | }; |
40 | |
41 | #ifdef CONFIG_HAS_IOPORT |
42 | |
43 | static int subdev_8255_io(struct comedi_device *dev, |
44 | int dir, int port, int data, unsigned long regbase) |
45 | { |
46 | if (dir) { |
47 | outb(value: data, port: dev->iobase + regbase + port); |
48 | return 0; |
49 | } |
50 | return inb(port: dev->iobase + regbase + port); |
51 | } |
52 | |
53 | #endif /* CONFIG_HAS_IOPORT */ |
54 | |
55 | static int subdev_8255_mmio(struct comedi_device *dev, |
56 | int dir, int port, int data, unsigned long regbase) |
57 | { |
58 | if (dir) { |
59 | writeb(val: data, addr: dev->mmio + regbase + port); |
60 | return 0; |
61 | } |
62 | return readb(addr: dev->mmio + regbase + port); |
63 | } |
64 | |
65 | static int subdev_8255_insn(struct comedi_device *dev, |
66 | struct comedi_subdevice *s, |
67 | struct comedi_insn *insn, |
68 | unsigned int *data) |
69 | { |
70 | struct subdev_8255_private *spriv = s->private; |
71 | unsigned long context = spriv->context; |
72 | unsigned int mask; |
73 | unsigned int v; |
74 | |
75 | mask = comedi_dio_update_state(s, data); |
76 | if (mask) { |
77 | if (mask & 0xff) |
78 | spriv->io(dev, 1, I8255_DATA_A_REG, |
79 | s->state & 0xff, context); |
80 | if (mask & 0xff00) |
81 | spriv->io(dev, 1, I8255_DATA_B_REG, |
82 | (s->state >> 8) & 0xff, context); |
83 | if (mask & 0xff0000) |
84 | spriv->io(dev, 1, I8255_DATA_C_REG, |
85 | (s->state >> 16) & 0xff, context); |
86 | } |
87 | |
88 | v = spriv->io(dev, 0, I8255_DATA_A_REG, 0, context); |
89 | v |= (spriv->io(dev, 0, I8255_DATA_B_REG, 0, context) << 8); |
90 | v |= (spriv->io(dev, 0, I8255_DATA_C_REG, 0, context) << 16); |
91 | |
92 | data[1] = v; |
93 | |
94 | return insn->n; |
95 | } |
96 | |
97 | static void subdev_8255_do_config(struct comedi_device *dev, |
98 | struct comedi_subdevice *s) |
99 | { |
100 | struct subdev_8255_private *spriv = s->private; |
101 | unsigned long context = spriv->context; |
102 | int config; |
103 | |
104 | config = I8255_CTRL_CW; |
105 | /* 1 in io_bits indicates output, 1 in config indicates input */ |
106 | if (!(s->io_bits & 0x0000ff)) |
107 | config |= I8255_CTRL_A_IO; |
108 | if (!(s->io_bits & 0x00ff00)) |
109 | config |= I8255_CTRL_B_IO; |
110 | if (!(s->io_bits & 0x0f0000)) |
111 | config |= I8255_CTRL_C_LO_IO; |
112 | if (!(s->io_bits & 0xf00000)) |
113 | config |= I8255_CTRL_C_HI_IO; |
114 | |
115 | spriv->io(dev, 1, I8255_CTRL_REG, config, context); |
116 | } |
117 | |
118 | static int subdev_8255_insn_config(struct comedi_device *dev, |
119 | struct comedi_subdevice *s, |
120 | struct comedi_insn *insn, |
121 | unsigned int *data) |
122 | { |
123 | unsigned int chan = CR_CHAN(insn->chanspec); |
124 | unsigned int mask; |
125 | int ret; |
126 | |
127 | if (chan < 8) |
128 | mask = 0x0000ff; |
129 | else if (chan < 16) |
130 | mask = 0x00ff00; |
131 | else if (chan < 20) |
132 | mask = 0x0f0000; |
133 | else |
134 | mask = 0xf00000; |
135 | |
136 | ret = comedi_dio_insn_config(dev, s, insn, data, mask); |
137 | if (ret) |
138 | return ret; |
139 | |
140 | subdev_8255_do_config(dev, s); |
141 | |
142 | return insn->n; |
143 | } |
144 | |
145 | static int __subdev_8255_init(struct comedi_device *dev, |
146 | struct comedi_subdevice *s, |
147 | int (*io)(struct comedi_device *dev, |
148 | int dir, int port, int data, |
149 | unsigned long context), |
150 | unsigned long context) |
151 | { |
152 | struct subdev_8255_private *spriv; |
153 | |
154 | if (!io) |
155 | return -EINVAL; |
156 | |
157 | spriv = comedi_alloc_spriv(s, size: sizeof(*spriv)); |
158 | if (!spriv) |
159 | return -ENOMEM; |
160 | |
161 | spriv->context = context; |
162 | spriv->io = io; |
163 | |
164 | s->type = COMEDI_SUBD_DIO; |
165 | s->subdev_flags = SDF_READABLE | SDF_WRITABLE; |
166 | s->n_chan = 24; |
167 | s->range_table = &range_digital; |
168 | s->maxdata = 1; |
169 | s->insn_bits = subdev_8255_insn; |
170 | s->insn_config = subdev_8255_insn_config; |
171 | |
172 | subdev_8255_do_config(dev, s); |
173 | |
174 | return 0; |
175 | } |
176 | |
177 | #ifdef CONFIG_HAS_IOPORT |
178 | |
179 | /** |
180 | * subdev_8255_io_init - initialize DIO subdevice for driving I/O mapped 8255 |
181 | * @dev: comedi device owning subdevice |
182 | * @s: comedi subdevice to initialize |
183 | * @regbase: offset of 8255 registers from dev->iobase |
184 | * |
185 | * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. |
186 | * |
187 | * Return: -ENOMEM if failed to allocate memory, zero on success. |
188 | */ |
189 | int subdev_8255_io_init(struct comedi_device *dev, struct comedi_subdevice *s, |
190 | unsigned long regbase) |
191 | { |
192 | return __subdev_8255_init(dev, s, io: subdev_8255_io, context: regbase); |
193 | } |
194 | EXPORT_SYMBOL_GPL(subdev_8255_io_init); |
195 | |
196 | #endif /* CONFIG_HAS_IOPORT */ |
197 | |
198 | /** |
199 | * subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255 |
200 | * @dev: comedi device owning subdevice |
201 | * @s: comedi subdevice to initialize |
202 | * @regbase: offset of 8255 registers from dev->mmio |
203 | * |
204 | * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. |
205 | * |
206 | * Return: -ENOMEM if failed to allocate memory, zero on success. |
207 | */ |
208 | int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s, |
209 | unsigned long regbase) |
210 | { |
211 | return __subdev_8255_init(dev, s, io: subdev_8255_mmio, context: regbase); |
212 | } |
213 | EXPORT_SYMBOL_GPL(subdev_8255_mm_init); |
214 | |
215 | /** |
216 | * subdev_8255_cb_init - initialize DIO subdevice for driving callback-mapped 8255 |
217 | * @dev: comedi device owning subdevice |
218 | * @s: comedi subdevice to initialize |
219 | * @io: register I/O call-back function |
220 | * @context: call-back context |
221 | * |
222 | * Initializes a comedi subdevice as a DIO subdevice driving an 8255 chip. |
223 | * |
224 | * The prototype of the I/O call-back function is of the following form: |
225 | * |
226 | * int my_8255_callback(struct comedi_device *dev, int dir, int port, |
227 | * int data, unsigned long context); |
228 | * |
229 | * where 'dev', and 'context' match the values passed to this function, |
230 | * 'port' is the 8255 port number 0 to 3 (including the control port), 'dir' |
231 | * is the direction (0 for read, 1 for write) and 'data' is the value to be |
232 | * written. It should return 0 if writing or the value read if reading. |
233 | * |
234 | * |
235 | * Return: -ENOMEM if failed to allocate memory, zero on success. |
236 | */ |
237 | int subdev_8255_cb_init(struct comedi_device *dev, struct comedi_subdevice *s, |
238 | int (*io)(struct comedi_device *dev, int dir, int port, |
239 | int data, unsigned long context), |
240 | unsigned long context) |
241 | { |
242 | return __subdev_8255_init(dev, s, io, context); |
243 | } |
244 | EXPORT_SYMBOL_GPL(subdev_8255_cb_init); |
245 | |
246 | /** |
247 | * subdev_8255_regbase - get offset of 8255 registers or call-back context |
248 | * @s: comedi subdevice |
249 | * |
250 | * Returns the 'regbase' or 'context' parameter that was previously passed to |
251 | * subdev_8255_io_init(), subdev_8255_mm_init(), or subdev_8255_cb_init() to |
252 | * set up the subdevice. Only valid if the subdevice was set up successfully. |
253 | */ |
254 | unsigned long subdev_8255_regbase(struct comedi_subdevice *s) |
255 | { |
256 | struct subdev_8255_private *spriv = s->private; |
257 | |
258 | return spriv->context; |
259 | } |
260 | EXPORT_SYMBOL_GPL(subdev_8255_regbase); |
261 | |
262 | static int __init comedi_8255_module_init(void) |
263 | { |
264 | return 0; |
265 | } |
266 | module_init(comedi_8255_module_init); |
267 | |
268 | static void __exit comedi_8255_module_exit(void) |
269 | { |
270 | } |
271 | module_exit(comedi_8255_module_exit); |
272 | |
273 | MODULE_AUTHOR("Comedi https://www.comedi.org" ); |
274 | MODULE_DESCRIPTION("Comedi: Generic 8255 digital I/O support" ); |
275 | MODULE_LICENSE("GPL" ); |
276 | |