comedi_8254.h

  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 */