diff options
Diffstat (limited to 'hw/max7310.c')
| -rw-r--r-- | hw/max7310.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/hw/max7310.c b/hw/max7310.c new file mode 100644 index 0000000000..a4aaf17d29 --- /dev/null +++ b/hw/max7310.c @@ -0,0 +1,188 @@ +/* + * MAX7310 8-port GPIO expansion chip. + * + * Copyright (c) 2006 Openedhand Ltd. + * Written by Andrzej Zaborowski <balrog@zabor.org> + * + * This file is licensed under GNU GPL. + */ + +#include "vl.h" + +struct max7310_s { + i2c_slave i2c; + int i2c_command_byte; + int len; + + uint8_t level; + uint8_t direction; + uint8_t polarity; + uint8_t status; + uint8_t command; + qemu_irq handler[8]; + qemu_irq *gpio_in; +}; + +void max7310_reset(i2c_slave *i2c) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + s->level &= s->direction; + s->direction = 0xff; + s->polarity = 0xf0; + s->status = 0x01; + s->command = 0x00; +} + +static int max7310_rx(i2c_slave *i2c) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + + switch (s->command) { + case 0x00: /* Input port */ + return s->level ^ s->polarity; + break; + + case 0x01: /* Output port */ + return s->level & ~s->direction; + break; + + case 0x02: /* Polarity inversion */ + return s->polarity; + + case 0x03: /* Configuration */ + return s->direction; + + case 0x04: /* Timeout */ + return s->status; + break; + + case 0xff: /* Reserved */ + return 0xff; + + default: +#ifdef VERBOSE + printf("%s: unknown register %02x\n", __FUNCTION__, s->command); +#endif + break; + } + return 0xff; +} + +static int max7310_tx(i2c_slave *i2c, uint8_t data) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + uint8_t diff; + int line; + + if (s->len ++ > 1) { +#ifdef VERBOSE + printf("%s: message too long (%i bytes)\n", __FUNCTION__, s->len); +#endif + return 1; + } + + if (s->i2c_command_byte) { + s->command = data; + s->i2c_command_byte = 0; + return 0; + } + + switch (s->command) { + case 0x01: /* Output port */ + for (diff = (data ^ s->level) & ~s->direction; diff; + diff &= ~(1 << line)) { + line = ffs(diff) - 1; + if (s->handler[line]) + qemu_set_irq(s->handler[line], (data >> line) & 1); + } + s->level = (s->level & s->direction) | (data & ~s->direction); + break; + + case 0x02: /* Polarity inversion */ + s->polarity = data; + break; + + case 0x03: /* Configuration */ + s->level &= ~(s->direction ^ data); + s->direction = data; + break; + + case 0x04: /* Timeout */ + s->status = data; + break; + + case 0x00: /* Input port - ignore writes */ + break; + default: +#ifdef VERBOSE + printf("%s: unknown register %02x\n", __FUNCTION__, s->command); +#endif + return 1; + } + + return 0; +} + +static void max7310_event(i2c_slave *i2c, enum i2c_event event) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + s->len = 0; + + switch (event) { + case I2C_START_SEND: + s->i2c_command_byte = 1; + break; + case I2C_FINISH: + if (s->len == 1) +#ifdef VERBOSE + printf("%s: message too short (%i bytes)\n", __FUNCTION__, s->len); +#endif + break; + default: + break; + } +} + +static void max7310_gpio_set(void *opaque, int line, int level) +{ + struct max7310_s *s = (struct max7310_s *) opaque; + if (line >= sizeof(s->handler) / sizeof(*s->handler) || line < 0) + cpu_abort(cpu_single_env, "bad GPIO line"); + + if (level) + s->level |= s->direction & (1 << line); + else + s->level &= ~(s->direction & (1 << line)); +} + +/* MAX7310 is SMBus-compatible (can be used with only SMBus protocols), + * but also accepts sequences that are not SMBus so return an I2C device. */ +struct i2c_slave *max7310_init(i2c_bus *bus) +{ + struct max7310_s *s = (struct max7310_s *) + i2c_slave_init(bus, 0, sizeof(struct max7310_s)); + s->i2c.event = max7310_event; + s->i2c.recv = max7310_rx; + s->i2c.send = max7310_tx; + s->gpio_in = qemu_allocate_irqs(max7310_gpio_set, s, + sizeof(s->handler) / sizeof(*s->handler)); + + max7310_reset(&s->i2c); + + return &s->i2c; +} + +qemu_irq *max7310_gpio_in_get(i2c_slave *i2c) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + return s->gpio_in; +} + +void max7310_gpio_out_set(i2c_slave *i2c, int line, qemu_irq handler) +{ + struct max7310_s *s = (struct max7310_s *) i2c; + if (line >= sizeof(s->handler) / sizeof(*s->handler) || line < 0) + cpu_abort(cpu_single_env, "bad GPIO line"); + + s->handler[line] = handler; +} |