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 <[email protected]> 6 * 7 * COMEDI - Linux Control and Measurement Device Interface 8 * Copyright (C) 2000 David A. Schleef <[email protected]> 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 18 struct comedi_device; 19 struct comedi_insn; 20 struct 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 62 struct 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 */ 73 typedef 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 */ 94 struct 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 }; 114 115 unsigned int comedi_8254_status(struct comedi_8254 *i8254, 116 unsigned int counter); 117 unsigned int comedi_8254_read(struct comedi_8254 *i8254, unsigned int counter); 118 void comedi_8254_write(struct comedi_8254 *i8254, 119 unsigned int counter, unsigned int val); 120 121 int comedi_8254_set_mode(struct comedi_8254 *i8254, 122 unsigned int counter, unsigned int mode); 123 int comedi_8254_load(struct comedi_8254 *i8254, 124 unsigned int counter, unsigned int val, unsigned int mode); 125 126 void comedi_8254_pacer_enable(struct comedi_8254 *i8254, 127 unsigned int counter1, unsigned int counter2, 128 bool enable); 129 void comedi_8254_update_divisors(struct comedi_8254 *i8254); 130 void comedi_8254_cascade_ns_to_timer(struct comedi_8254 *i8254, 131 unsigned int *nanosec, unsigned int flags); 132 void comedi_8254_ns_to_timer(struct comedi_8254 *i8254, 133 unsigned int *nanosec, unsigned int flags); 134 135 void comedi_8254_set_busy(struct comedi_8254 *i8254, 136 unsigned int counter, bool busy); 137 138 void comedi_8254_subdevice_init(struct comedi_subdevice *s, 139 struct comedi_8254 *i8254); 140 141 #ifdef CONFIG_HAS_IOPORT 142 struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase, 143 unsigned int osc_base, 144 unsigned int iosize, 145 unsigned int regshift); 146 #else 147 static 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 155 156 struct 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 */ 162