1 /* SPDX-License-Identifier: GPL-2.0+ */
4 * Generic 8254 timer/counter support
5 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com>
7 * COMEDI - Linux Control and Measurement Device Interface
8 * Copyright (C) 2000 David A. Schleef <ds@schleef.org>
11 #ifndef _COMEDI_8254_H
12 #define _COMEDI_8254_H
14 #include <linux/types.h>
18 struct comedi_subdevice;
21 * Common oscillator base values in nanoseconds
23 #define I8254_OSC_BASE_10MHZ 100
24 #define I8254_OSC_BASE_5MHZ 200
25 #define I8254_OSC_BASE_4MHZ 250
26 #define I8254_OSC_BASE_2MHZ 500
27 #define I8254_OSC_BASE_1MHZ 1000
28 #define I8254_OSC_BASE_100KHZ 10000
29 #define I8254_OSC_BASE_10KHZ 100000
30 #define I8254_OSC_BASE_1KHZ 1000000
33 * I/O access size used to read/write registers
40 * Register map for generic 8254 timer (I8254_IO8 with 0 regshift)
42 #define I8254_COUNTER0_REG 0x00
43 #define I8254_COUNTER1_REG 0x01
44 #define I8254_COUNTER2_REG 0x02
45 #define I8254_CTRL_REG 0x03
46 #define I8254_CTRL_SEL_CTR(x) ((x) << 6)
47 #define I8254_CTRL_READBACK(x) (I8254_CTRL_SEL_CTR(3) | BIT(x))
48 #define I8254_CTRL_READBACK_COUNT I8254_CTRL_READBACK(4)
49 #define I8254_CTRL_READBACK_STATUS I8254_CTRL_READBACK(5)
50 #define I8254_CTRL_READBACK_SEL_CTR(x) (2 << (x))
51 #define I8254_CTRL_RW(x) (((x) & 0x3) << 4)
52 #define I8254_CTRL_LATCH I8254_CTRL_RW(0)
53 #define I8254_CTRL_LSB_ONLY I8254_CTRL_RW(1)
54 #define I8254_CTRL_MSB_ONLY I8254_CTRL_RW(2)
55 #define I8254_CTRL_LSB_MSB I8254_CTRL_RW(3)
57 /* counter maps zero to 0x10000 */
58 #define I8254_MAX_COUNT 0x10000
61 * struct comedi_8254 - private data used by this module
62 * @iobase: PIO base address of the registers (in/out)
63 * @mmio: MMIO base address of the registers (read/write)
64 * @iosize: I/O size used to access the registers (b/w/l)
65 * @regshift: register gap shift
66 * @osc_base: cascaded oscillator speed in ns
67 * @divisor: divisor for single counter
68 * @divisor1: divisor loaded into first cascaded counter
69 * @divisor2: divisor loaded into second cascaded counter
70 * #next_div: next divisor for single counter
71 * @next_div1: next divisor to use for first cascaded counter
72 * @next_div2: next divisor to use for second cascaded counter
73 * @clock_src; current clock source for each counter (driver specific)
74 * @gate_src; current gate source for each counter (driver specific)
75 * @busy: flags used to indicate that a counter is "busy"
76 * @insn_config: driver specific (*insn_config) callback
82 unsigned int regshift;
83 unsigned int osc_base;
85 unsigned int divisor1;
86 unsigned int divisor2;
87 unsigned int next_div;
88 unsigned int next_div1;
89 unsigned int next_div2;
90 unsigned int clock_src[3];
91 unsigned int gate_src[3];
94 int (*insn_config)(struct comedi_device *dev,
95 struct comedi_subdevice *s,
96 struct comedi_insn *insn, unsigned int *data);
99 unsigned int comedi_8254_status(struct comedi_8254 *i8254,
100 unsigned int counter);
101 unsigned int comedi_8254_read(struct comedi_8254 *i8254, unsigned int counter);
102 void comedi_8254_write(struct comedi_8254 *i8254,
103 unsigned int counter, unsigned int val);
105 int comedi_8254_set_mode(struct comedi_8254 *i8254,
106 unsigned int counter, unsigned int mode);
107 int comedi_8254_load(struct comedi_8254 *i8254,
108 unsigned int counter, unsigned int val, unsigned int mode);
110 void comedi_8254_pacer_enable(struct comedi_8254 *i8254,
111 unsigned int counter1, unsigned int counter2,
113 void comedi_8254_update_divisors(struct comedi_8254 *i8254);
114 void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *i8254,
115 unsigned int *nanosec, unsigned int flags);
116 void comedi_8254_ns_to_timer(struct comedi_8254 *i8254,
117 unsigned int *nanosec, unsigned int flags);
119 void comedi_8254_set_busy(struct comedi_8254 *i8254,
120 unsigned int counter, bool busy);
122 void comedi_8254_subdevice_init(struct comedi_subdevice *s,
123 struct comedi_8254 *i8254);
125 struct comedi_8254 *comedi_8254_init(unsigned long iobase,
126 unsigned int osc_base,
128 unsigned int regshift);
129 struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
130 unsigned int osc_base,
132 unsigned int regshift);
134 #endif /* _COMEDI_8254_H */