/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * comedi_8254.h
 * Generic 8254 timer/counter support
 * Copyright (C) 2014 H Hartley Sweeten <[email protected]>
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 2000 David A. Schleef <[email protected]>
 */

#ifndef _COMEDI_8254_H
#define _COMEDI_8254_H

#include <linux/types.h>

struct comedi_device;
struct comedi_insn;
struct comedi_subdevice;

/*
 * Common oscillator base values in nanoseconds
 */
#define I8254_OSC_BASE_10MHZ    100
#define I8254_OSC_BASE_5MHZ    200
#define I8254_OSC_BASE_4MHZ    250
#define I8254_OSC_BASE_2MHZ    500
#define I8254_OSC_BASE_1MHZ    1000
#define I8254_OSC_BASE_100KHZ    10000
#define I8254_OSC_BASE_10KHZ    100000
#define I8254_OSC_BASE_1KHZ    1000000

/*
 * I/O access size used to read/write registers
 */
#define I8254_IO8        1
#define I8254_IO16        2
#define I8254_IO32        4

/*
 * Register map for generic 8254 timer (I8254_IO8 with 0 regshift)
 */
#define I8254_COUNTER0_REG        0x00
#define I8254_COUNTER1_REG        0x01
#define I8254_COUNTER2_REG        0x02
#define I8254_CTRL_REG            0x03
#define I8254_CTRL_SEL_CTR(x)        ((x) << 6)
#define I8254_CTRL_READBACK(x)        (I8254_CTRL_SEL_CTR(3) | BIT(x))
#define I8254_CTRL_READBACK_COUNT    I8254_CTRL_READBACK(4)
#define I8254_CTRL_READBACK_STATUS    I8254_CTRL_READBACK(5)
#define I8254_CTRL_READBACK_SEL_CTR(x)    (2 << (x))
#define I8254_CTRL_RW(x)        (((x) & 0x3) << 4)
#define I8254_CTRL_LATCH        I8254_CTRL_RW(0)
#define I8254_CTRL_LSB_ONLY        I8254_CTRL_RW(1)
#define I8254_CTRL_MSB_ONLY        I8254_CTRL_RW(2)
#define I8254_CTRL_LSB_MSB        I8254_CTRL_RW(3)

/* counter maps zero to 0x10000 */
#define I8254_MAX_COUNT            0x10000

/**
 * struct comedi_8254 - private data used by this module
 * @iobase:        PIO base address of the registers (in/out)
 * @mmio:        MMIO base address of the registers (read/write)
 * @iosize:        I/O size used to access the registers (b/w/l)
 * @regshift:        register gap shift
 * @osc_base:        cascaded oscillator speed in ns
 * @divisor:        divisor for single counter
 * @divisor1:        divisor loaded into first cascaded counter
 * @divisor2:        divisor loaded into second cascaded counter
 * #next_div:        next divisor for single counter
 * @next_div1:        next divisor to use for first cascaded counter
 * @next_div2:        next divisor to use for second cascaded counter
 * @clock_src;        current clock source for each counter (driver specific)
 * @gate_src;        current gate source  for each counter (driver specific)
 * @busy:        flags used to indicate that a counter is "busy"
 * @insn_config:    driver specific (*insn_config) callback
 */
struct comedi_8254 {
    unsigned long iobase;
    void __iomem *mmio;
    unsigned int iosize;
    unsigned int regshift;
    unsigned int osc_base;
    unsigned int divisor;
    unsigned int divisor1;
    unsigned int divisor2;
    unsigned int next_div;
    unsigned int next_div1;
    unsigned int next_div2;
    unsigned int clock_src[3];
    unsigned int gate_src[3];
    bool busy[3];

    int (*insn_config)(struct comedi_device *dev,
               struct comedi_subdevice *s,
               struct comedi_insn *insn, unsigned int *data);
};

unsigned int comedi_8254_status(struct comedi_8254 *i8254,
                unsigned int counter);
unsigned int comedi_8254_read(struct comedi_8254 *i8254, unsigned int counter);
void comedi_8254_write(struct comedi_8254 *i8254,
               unsigned int counter, unsigned int val);

int comedi_8254_set_mode(struct comedi_8254 *i8254,
             unsigned int counter, unsigned int mode);
int comedi_8254_load(struct comedi_8254 *i8254,
             unsigned int counter, unsigned int val, unsigned int mode);

void comedi_8254_pacer_enable(struct comedi_8254 *i8254,
                  unsigned int counter1, unsigned int counter2,
                  bool enable);
void comedi_8254_update_divisors(struct comedi_8254 *i8254);
void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *i8254,
                     unsigned int *nanosec, unsigned int flags);
void comedi_8254_ns_to_timer(struct comedi_8254 *i8254,
                 unsigned int *nanosec, unsigned int flags);

void comedi_8254_set_busy(struct comedi_8254 *i8254,
              unsigned int counter, bool busy);

void comedi_8254_subdevice_init(struct comedi_subdevice *s,
                struct comedi_8254 *i8254);

struct comedi_8254 *comedi_8254_init(unsigned long iobase,
                     unsigned int osc_base,
                     unsigned int iosize,
                     unsigned int regshift);
struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio,
                    unsigned int osc_base,
                    unsigned int iosize,
                    unsigned int regshift);

#endif    /* _COMEDI_8254_H */