3 * Generic 8254 timer/counter support
4 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
6 * COMEDI - Linux Control and Measurement Device Interface
7 * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
20 #ifndef _COMEDI_8254_H
21 #define _COMEDI_8254_H
23 #include <linux/types.h>
27 struct comedi_subdevice;
30 * Common oscillator base values in nanoseconds
32 #define I8254_OSC_BASE_10MHZ 100
33 #define I8254_OSC_BASE_5MHZ 200
34 #define I8254_OSC_BASE_4MHZ 250
35 #define I8254_OSC_BASE_2MHZ 500
36 #define I8254_OSC_BASE_1MHZ 1000
37 #define I8254_OSC_BASE_100KHZ 10000
38 #define I8254_OSC_BASE_10KHZ 100000
39 #define I8254_OSC_BASE_1KHZ 1000000
42 * I/O access size used to read/write registers
49 * Register map for generic 8254 timer (I8254_IO8 with 0 regshift)
51 #define I8254_COUNTER0_REG 0x00
52 #define I8254_COUNTER1_REG 0x01
53 #define I8254_COUNTER2_REG 0x02
54 #define I8254_CTRL_REG 0x03
55 #define I8254_CTRL_SEL_CTR(x) ((x) << 6)
56 #define I8254_CTRL_READBACK_COUNT ((3 << 6) | (1 << 4))
57 #define I8254_CTRL_READBACK_STATUS ((3 << 6) | (1 << 5))
58 #define I8254_CTRL_READBACK_SEL_CTR(x) (2 << (x))
59 #define I8254_CTRL_LATCH (0 << 4)
60 #define I8254_CTRL_LSB_ONLY (1 << 4)
61 #define I8254_CTRL_MSB_ONLY (2 << 4)
62 #define I8254_CTRL_LSB_MSB (3 << 4)
64 /* counter maps zero to 0x10000 */
65 #define I8254_MAX_COUNT 0x10000
68 * struct comedi_8254 - private data used by this module
69 * @iobase: PIO base address of the registers (in/out)
70 * @mmio: MMIO base address of the registers (read/write)
71 * @iosize: I/O size used to access the registers (b/w/l)
72 * @regshift: register gap shift
73 * @osc_base: cascaded oscillator speed in ns
74 * @divisor: divisor for single counter
75 * @divisor1: divisor loaded into first cascaded counter
76 * @divisor2: divisor loaded into second cascaded counter
77 * #next_div: next divisor for single counter
78 * @next_div1: next divisor to use for first cascaded counter
79 * @next_div2: next divisor to use for second cascaded counter
80 * @clock_src; current clock source for each counter (driver specific)
81 * @gate_src; current gate source for each counter (driver specific)
82 * @busy: flags used to indicate that a counter is "busy"
83 * @insn_config: driver specific (*insn_config) callback
89 unsigned int regshift;
90 unsigned int osc_base;
92 unsigned int divisor1;
93 unsigned int divisor2;
94 unsigned int next_div;
95 unsigned int next_div1;
96 unsigned int next_div2;
97 unsigned int clock_src[3];
98 unsigned int gate_src[3];
101 int (*insn_config)(struct comedi_device *, struct comedi_subdevice *s,
102 struct comedi_insn *, unsigned int *data);
105 unsigned int comedi_8254_status(struct comedi_8254 *, unsigned int counter);
106 unsigned int comedi_8254_read(struct comedi_8254 *, unsigned int counter);
107 void comedi_8254_write(struct comedi_8254 *,
108 unsigned int counter, unsigned int val);
110 int comedi_8254_set_mode(struct comedi_8254 *,
111 unsigned int counter, unsigned int mode);
112 int comedi_8254_load(struct comedi_8254 *,
113 unsigned int counter, unsigned int val, unsigned int mode);
115 void comedi_8254_pacer_enable(struct comedi_8254 *,
116 unsigned int counter1, unsigned int counter2,
118 void comedi_8254_update_divisors(struct comedi_8254 *);
119 void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *,
120 unsigned int *nanosec, unsigned int flags);
121 void comedi_8254_ns_to_timer(struct comedi_8254 *,
122 unsigned int *nanosec, unsigned int flags);
124 void comedi_8254_set_busy(struct comedi_8254 *,
125 unsigned int counter, bool busy);
127 void comedi_8254_subdevice_init(struct comedi_subdevice *,
128 struct comedi_8254 *);
130 struct comedi_8254 *comedi_8254_init(unsigned long iobase,
131 unsigned int osc_base,
133 unsigned int regshift);
134 struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
135 unsigned int osc_base,
137 unsigned int regshift);
139 #endif /* _COMEDI_8254_H */