accelerants/common/i2c.c

31 	I2c timings, rounded up (Philips 1995 i2c bus specification, p20)
94 wait_for_clk(const i2c_bus *bus, bigtime_t timeout)
99 	spin(bus->timing.r);
106 		bus->get_signals(bus->cookie, &clk, &data);
115 		spin(bus->timing.r);
122 send_start_condition(const i2c_bus *bus)
126 	bus->set_signals(bus->cookie, 1, 1);
128 	status = wait_for_clk(bus, bus->timing.start_timeout);
134 	spin(bus->timing.su_sta);
135 	bus->set_signals(bus->cookie, 1, 0);
136 	spin(bus->timing.hd_sta);
137 	bus->set_signals(bus->cookie, 0, 0);
138 	spin(bus->timing.f);
146 send_stop_condition(const i2c_bus *bus)
150 	bus->set_signals(bus->cookie, 0, 0);
151 	spin(bus->timing.r);
152 	bus->set_signals(bus->cookie, 1, 0);
155 	// to make the slave release bus control
156 	status = wait_for_clk(bus, bus->timing.ack_timeout);
162 	spin(bus->timing.su_sto);
163 	bus->set_signals(bus->cookie, 1, 1);
164 	spin(bus->timing.buf);
172 send_bit(const i2c_bus *bus, uint8 bit, int timeout)
178 	bus->set_signals(bus->cookie, 0, bit & 1);
179 	spin(bus->timing.su_dat);
180 	bus->set_signals(bus->cookie, 1, bit & 1);
182 	status = wait_for_clk(bus, timeout);
188 	spin(bus->timing.high);
189 	bus->set_signals(bus->cookie, 0, bit & 1);
190 	spin(bus->timing.f + bus->timing.low);
198 send_acknowledge(const i2c_bus *bus)
204 	bus->set_signals(bus->cookie, 0, 1);
205 	spin(bus->timing.su_dat);
206 	bus->set_signals(bus->cookie, 1, 1);
208 	status = wait_for_clk(bus, bus->timing.ack_start_timeout);
221 		bus->get_signals(bus->cookie, &clk, &data);
226 		if (system_time() - startTime > bus->timing.ack_timeout) {
228 				__func__, bus->timing.ack_timeout);
232 		spin(bus->timing.r);
238 	spin(bus->timing.high);
240 	bus->set_signals(bus->cookie, 0, 1);
241 	spin(bus->timing.f + bus->timing.low);
249 send_byte(const i2c_bus *bus, uint8 byte, bool acknowledge)
256 		status_t status = send_bit(bus, byte >> i,
257 			i == 7 ? bus->timing.byte_timeout : bus->timing.bit_timeout);
263 		return send_acknowledge(bus);
271 send_slave_address(const i2c_bus *bus, uint8 slaveAddress, bool isWrite)
276 	status = send_byte(bus, (slaveAddress & 0xfe) | (isWrite ? 0 : 1), true);
284 	// - 0000 010x - address reserved for different bus format
294 	return send_byte(bus, slaveAddress >> 8, true);
301 receive_bit(const i2c_bus *bus, bool *bit, int timeout)
306 	bus->set_signals(bus->cookie, 1, 1);
310 	status = wait_for_clk(bus, timeout);
316 	bus->get_signals(bus->cookie, &clk, &data);
319 	spin(bus->timing.high);
322 	bus->set_signals(bus->cookie, 0, 1);
325 	spin(bus->timing.f + bus->timing.low);
339 receive_byte(const i2c_bus *bus, uint8 *resultByte, bool acknowledge)
345 	bus->set_signals(bus->cookie, 0, 1);
350 		status_t status = receive_bit(bus, &bit,
351 			i == 7 ? bus->timing.byte_timeout : bus->timing.bit_timeout);
362 	return send_bit(bus, acknowledge ? 0 : 1, bus->timing.bit_timeout);
368 send_bytes(const i2c_bus *bus, const uint8 *writeBuffer, ssize_t writeLength)
373 		status_t status = send_byte(bus, *writeBuffer, true);
384 receive_bytes(const i2c_bus *bus, uint8 *readBuffer, ssize_t readLength)
389 		status_t status = receive_byte(bus, readBuffer, readLength > 1);
403 i2c_send_receive_callback(const i2c_bus *bus, uint32 slaveAddress, const uint8 *writeBuffer,
413 	status = send_start_condition(bus);
417 	status = send_slave_address(bus, slaveAddress, true);
421 	status = send_bytes(bus, writeBuffer, writeLength);
425 	status = send_start_condition(bus);
429 	status = send_slave_address(bus, slaveAddress, false);
433 	status = receive_bytes(bus, readBuffer, readLength);
437 	return send_stop_condition(bus);
441 	send_stop_condition(bus);