1/* SPDX-License-Identifier: GPL-2.0+ */
2/*
3 * comedi_8254.h
4 * Generic 8254 timer/counter support
5 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
6 *
7 * COMEDI - Linux Control and Measurement Device Interface
8 * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
9 */
10
11#ifndef _COMEDI_8254_H
12#define _COMEDI_8254_H
13
14#include <linux/types.h>
15#include <linux/errno.h>
16#include <linux/err.h>
17
18struct comedi_device;
19struct comedi_insn;
20struct comedi_subdevice;
21
22/*
23 * Common oscillator base values in nanoseconds
24 */
25#define I8254_OSC_BASE_10MHZ 100
26#define I8254_OSC_BASE_5MHZ 200
27#define I8254_OSC_BASE_4MHZ 250
28#define I8254_OSC_BASE_2MHZ 500
29#define I8254_OSC_BASE_1MHZ 1000
30#define I8254_OSC_BASE_100KHZ 10000
31#define I8254_OSC_BASE_10KHZ 100000
32#define I8254_OSC_BASE_1KHZ 1000000
33
34/*
35 * I/O access size used to read/write registers
36 */
37#define I8254_IO8 1
38#define I8254_IO16 2
39#define I8254_IO32 4
40
41/*
42 * Register map for generic 8254 timer (I8254_IO8 with 0 regshift)
43 */
44#define I8254_COUNTER0_REG 0x00
45#define I8254_COUNTER1_REG 0x01
46#define I8254_COUNTER2_REG 0x02
47#define I8254_CTRL_REG 0x03
48#define I8254_CTRL_SEL_CTR(x) ((x) << 6)
49#define I8254_CTRL_READBACK(x) (I8254_CTRL_SEL_CTR(3) | BIT(x))
50#define I8254_CTRL_READBACK_COUNT I8254_CTRL_READBACK(4)
51#define I8254_CTRL_READBACK_STATUS I8254_CTRL_READBACK(5)
52#define I8254_CTRL_READBACK_SEL_CTR(x) (2 << (x))
53#define I8254_CTRL_RW(x) (((x) & 0x3) << 4)
54#define I8254_CTRL_LATCH I8254_CTRL_RW(0)
55#define I8254_CTRL_LSB_ONLY I8254_CTRL_RW(1)
56#define I8254_CTRL_MSB_ONLY I8254_CTRL_RW(2)
57#define I8254_CTRL_LSB_MSB I8254_CTRL_RW(3)
58
59/* counter maps zero to 0x10000 */
60#define I8254_MAX_COUNT 0x10000
61
62struct comedi_8254;
63
64/**
65 * typedef comedi_8254_iocb_fn - call-back function type for 8254 register access
66 * @i8254: pointer to struct comedi_8254
67 * @dir: direction (0 = read, 1 = write)
68 * @reg: register number
69 * @val: value to write
70 *
71 * Return: Register value when reading, 0 when writing.
72 */
73typedef unsigned int comedi_8254_iocb_fn(struct comedi_8254 *i8254, int dir,
74 unsigned int reg, unsigned int val);
75
76/**
77 * struct comedi_8254 - private data used by this module
78 * @iocb: I/O call-back function for register access
79 * @context: context for register access (e.g. a base address)
80 * @iosize: I/O size used to access the registers (b/w/l)
81 * @regshift: register gap shift
82 * @osc_base: cascaded oscillator speed in ns
83 * @divisor: divisor for single counter
84 * @divisor1: divisor loaded into first cascaded counter
85 * @divisor2: divisor loaded into second cascaded counter
86 * #next_div: next divisor for single counter
87 * @next_div1: next divisor to use for first cascaded counter
88 * @next_div2: next divisor to use for second cascaded counter
89 * @clock_src; current clock source for each counter (driver specific)
90 * @gate_src; current gate source for each counter (driver specific)
91 * @busy: flags used to indicate that a counter is "busy"
92 * @insn_config: driver specific (*insn_config) callback
93 */
94struct comedi_8254 {
95 comedi_8254_iocb_fn *iocb;
96 unsigned long context;
97 unsigned int iosize;
98 unsigned int regshift;
99 unsigned int osc_base;
100 unsigned int divisor;
101 unsigned int divisor1;
102 unsigned int divisor2;
103 unsigned int next_div;
104 unsigned int next_div1;
105 unsigned int next_div2;
106 unsigned int clock_src[3];
107 unsigned int gate_src[3];
108 bool busy[3];
109
110 int (*insn_config)(struct comedi_device *dev,
111 struct comedi_subdevice *s,
112 struct comedi_insn *insn, unsigned int *data);
113};
114
115unsigned int comedi_8254_status(struct comedi_8254 *i8254,
116 unsigned int counter);
117unsigned int comedi_8254_read(struct comedi_8254 *i8254, unsigned int counter);
118void comedi_8254_write(struct comedi_8254 *i8254,
119 unsigned int counter, unsigned int val);
120
121int comedi_8254_set_mode(struct comedi_8254 *i8254,
122 unsigned int counter, unsigned int mode);
123int comedi_8254_load(struct comedi_8254 *i8254,
124 unsigned int counter, unsigned int val, unsigned int mode);
125
126void comedi_8254_pacer_enable(struct comedi_8254 *i8254,
127 unsigned int counter1, unsigned int counter2,
128 bool enable);
129void comedi_8254_update_divisors(struct comedi_8254 *i8254);
130void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *i8254,
131 unsigned int *nanosec, unsigned int flags);
132void comedi_8254_ns_to_timer(struct comedi_8254 *i8254,
133 unsigned int *nanosec, unsigned int flags);
134
135void comedi_8254_set_busy(struct comedi_8254 *i8254,
136 unsigned int counter, bool busy);
137
138void comedi_8254_subdevice_init(struct comedi_subdevice *s,
139 struct comedi_8254 *i8254);
140
141#ifdef CONFIG_HAS_IOPORT
142struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
143 unsigned int osc_base,
144 unsigned int iosize,
145 unsigned int regshift);
146#else
147static inline struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
148 unsigned int osc_base,
149 unsigned int iosize,
150 unsigned int regshift)
151{
152 return ERR_PTR(-ENXIO);
153}
154#endif
155
156struct comedi_8254 *comedi_8254_mm_alloc(void __iomem *mmio,
157 unsigned int osc_base,
158 unsigned int iosize,
159 unsigned int regshift);
160
161#endif /* _COMEDI_8254_H */
162

source code of linux/include/linux/comedi/comedi_8254.h