1 /* 2 * comedi_8254.h 3 * Generic 8254 timer/counter support 4 * Copyright (C) 2014 H Hartley Sweeten <hsweeten@visionengravers.com> 5 * 6 * COMEDI - Linux Control and Measurement Device Interface 7 * Copyright (C) 2000 David A. Schleef <ds@schleef.org> 8 * 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. 13 * 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. 18 */ 19 20 #ifndef _COMEDI_8254_H 21 #define _COMEDI_8254_H 22 23 /* 24 * Common oscillator base values in nanoseconds 25 */ 26 #define I8254_OSC_BASE_10MHZ 100 27 #define I8254_OSC_BASE_5MHZ 200 28 #define I8254_OSC_BASE_4MHZ 250 29 #define I8254_OSC_BASE_2MHZ 500 30 #define I8254_OSC_BASE_1MHZ 1000 31 #define I8254_OSC_BASE_100KHZ 10000 32 #define I8254_OSC_BASE_10KHZ 100000 33 #define I8254_OSC_BASE_1KHZ 1000000 34 35 /* 36 * I/O access size used to read/write registers 37 */ 38 #define I8254_IO8 1 39 #define I8254_IO16 2 40 #define I8254_IO32 4 41 42 /* 43 * Register map for generic 8254 timer (I8254_IO8 with 0 regshift) 44 */ 45 #define I8254_COUNTER0_REG 0x00 46 #define I8254_COUNTER1_REG 0x01 47 #define I8254_COUNTER2_REG 0x02 48 #define I8254_CTRL_REG 0x03 49 #define I8254_CTRL_SEL_CTR(x) ((x) << 6) 50 #define I8254_CTRL_READBACK_COUNT ((3 << 6) | (1 << 4)) 51 #define I8254_CTRL_READBACK_STATUS ((3 << 6) | (1 << 5)) 52 #define I8254_CTRL_READBACK_SEL_CTR(x) (2 << (x)) 53 #define I8254_CTRL_LATCH (0 << 4) 54 #define I8254_CTRL_LSB_ONLY (1 << 4) 55 #define I8254_CTRL_MSB_ONLY (2 << 4) 56 #define I8254_CTRL_LSB_MSB (3 << 4) 57 58 /* counter maps zero to 0x10000 */ 59 #define I8254_MAX_COUNT 0x10000 60 61 /** 62 * struct comedi_8254 - private data used by this module 63 * @iobase: PIO base address of the registers (in/out) 64 * @mmio: MMIO base address of the registers (read/write) 65 * @iosize: I/O size used to access the registers (b/w/l) 66 * @regshift: register gap shift 67 * @osc_base: cascaded oscillator speed in ns 68 * @divisor: divisor for single counter 69 * @divisor1: divisor loaded into first cascaded counter 70 * @divisor2: divisor loaded into second cascaded counter 71 * #next_div: next divisor for single counter 72 * @next_div1: next divisor to use for first cascaded counter 73 * @next_div2: next divisor to use for second cascaded counter 74 * @clock_src; current clock source for each counter (driver specific) 75 * @gate_src; current gate source for each counter (driver specific) 76 * @busy: flags used to indicate that a counter is "busy" 77 * @insn_config: driver specific (*insn_config) callback 78 */ 79 struct comedi_8254 { 80 unsigned long iobase; 81 void __iomem *mmio; 82 unsigned int iosize; 83 unsigned int regshift; 84 unsigned int osc_base; 85 unsigned int divisor; 86 unsigned int divisor1; 87 unsigned int divisor2; 88 unsigned int next_div; 89 unsigned int next_div1; 90 unsigned int next_div2; 91 unsigned int clock_src[3]; 92 unsigned int gate_src[3]; 93 bool busy[3]; 94 95 int (*insn_config)(struct comedi_device *, struct comedi_subdevice *s, 96 struct comedi_insn *, unsigned int *data); 97 }; 98 99 unsigned int comedi_8254_status(struct comedi_8254 *, unsigned int counter); 100 unsigned int comedi_8254_read(struct comedi_8254 *, unsigned int counter); 101 void comedi_8254_write(struct comedi_8254 *, 102 unsigned int counter, unsigned int val); 103 104 int comedi_8254_set_mode(struct comedi_8254 *, 105 unsigned int counter, unsigned int mode); 106 int comedi_8254_load(struct comedi_8254 *, 107 unsigned int counter, unsigned int val, unsigned int mode); 108 109 void comedi_8254_pacer_enable(struct comedi_8254 *, 110 unsigned int counter1, unsigned int counter2, 111 bool enable); 112 void comedi_8254_update_divisors(struct comedi_8254 *); 113 void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *, 114 unsigned int *nanosec, unsigned int flags); 115 void comedi_8254_ns_to_timer(struct comedi_8254 *, 116 unsigned int *nanosec, unsigned int flags); 117 118 void comedi_8254_set_busy(struct comedi_8254 *, 119 unsigned int counter, bool busy); 120 121 void comedi_8254_subdevice_init(struct comedi_subdevice *, 122 struct comedi_8254 *); 123 124 struct comedi_8254 *comedi_8254_init(unsigned long iobase, 125 unsigned int osc_base, 126 unsigned int iosize, 127 unsigned int regshift); 128 struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio, 129 unsigned int osc_base, 130 unsigned int iosize, 131 unsigned int regshift); 132 133 #endif /* _COMEDI_8254_H */ 134