mirror of
https://github.com/Telecominfraproject/OpenCellular.git
synced 2026-01-08 16:41:55 +00:00
Add I2C transmit/receive function
Implement a generalized I2C transmit-receive function that write-then-read blocks of raw data. Original 8-bit and 16-bit read/write functions are refactored. SMBus read-block protocol for ASCII string is also implemented based on this API. Signed-off-by: Rong Chang <rongchang@chromium.org> BUG=chrome-os-partner:8026,8316 TEST=manual: Type 'lightsaber' to check 8-bit read/write. Type 'charger' to check 16-bit read. Type 'charger input 4032' to check 16-bit write. Change-Id: I0ad3ad45b796d9ec03d8fbc1d643aa6a92d6343f
This commit is contained in:
Rong Chang
304
chip/lm4/i2c.c
304
chip/lm4/i2c.c
@@ -17,10 +17,21 @@
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#define NUM_PORTS 6
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#define LM4_I2C_MCS_RUN (1 << 0)
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#define LM4_I2C_MCS_START (1 << 1)
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#define LM4_I2C_MCS_STOP (1 << 2)
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#define LM4_I2C_MCS_ACK (1 << 3)
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#define LM4_I2C_MCS_HS (1 << 4)
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#define LM4_I2C_MCS_QCMD (1 << 5)
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#define START 1
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#define STOP 1
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#define NO_START 0
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#define NO_STOP 0
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static task_id_t task_waiting_on_port[NUM_PORTS];
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static struct mutex port_mutex[NUM_PORTS];
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static int wait_idle(int port)
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{
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int i;
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@@ -47,56 +58,113 @@ static int wait_idle(int port)
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return EC_SUCCESS;
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}
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/* Transmit one block of raw data, then receive one block of raw data.
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* <start> flag indicates this smbus session start from idle state.
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* <stop> flag means this session can be termicate with smbus stop bit
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*/
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static int i2c_transmit_receive(int port, int slave_addr,
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uint8_t *transmit_data, int transmit_size,
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uint8_t *receive_data, int receive_size,
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int start, int stop)
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{
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int rv, i;
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int started = start ? 0 : 1;
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uint32_t reg_mcs;
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int i2c_read16(int port, int slave_addr, int offset, int* data)
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if (transmit_size == 0 && receive_size == 0)
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return EC_SUCCESS;
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if (transmit_data) {
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LM4_I2C_MSA(port) = slave_addr & 0xff;
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for (i = 0; i < transmit_size; i++) {
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LM4_I2C_MDR(port) = transmit_data[i];
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/* Setup master control/status register
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* MCS sequence on multi-byte write:
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* 0x3 0x1 0x1 ... 0x1 0x5
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* Single byte write:
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* 0x7
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*/
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reg_mcs = LM4_I2C_MCS_RUN;
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/* Set start bit on first byte */
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if (!started) {
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started = 1;
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reg_mcs |= LM4_I2C_MCS_START;
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}
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/* Send stop bit if the stop flag is on,
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* and caller doesn't expect to receive
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* data.
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*/
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if (stop && receive_size == 0 && i ==
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(transmit_size - 1))
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reg_mcs |= LM4_I2C_MCS_STOP;
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LM4_I2C_MCS(port) = reg_mcs;
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rv = wait_idle(port);
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if (rv)
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return rv;
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}
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}
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if (receive_size) {
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if (transmit_size)
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/* resend start bit when change direction */
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started = 0;
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LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x01;
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for (i = 0; i < receive_size; i++) {
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LM4_I2C_MDR(port) = receive_data[i];
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/* MCS receive sequence on multi-byte read:
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* 0xb 0x9 0x9 ... 0x9 0x5
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* Single byte read:
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* 0x7
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*/
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reg_mcs = LM4_I2C_MCS_RUN;
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if (!started) {
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started = 1;
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reg_mcs |= LM4_I2C_MCS_START;
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}
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/* ACK all bytes except the last one */
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if (stop && i == (receive_size - 1))
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reg_mcs |= LM4_I2C_MCS_STOP;
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else
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reg_mcs |= LM4_I2C_MCS_ACK;
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LM4_I2C_MCS(port) = reg_mcs;
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rv = wait_idle(port);
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if (rv)
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return rv;
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receive_data[i] = LM4_I2C_MDR(port) & 0xff;
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}
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}
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return EC_SUCCESS;
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}
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int i2c_read16(int port, int slave_addr, int offset, int *data)
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{
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int rv;
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int d;
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uint8_t reg, buf[2];
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reg = offset & 0xff;
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/* I2C read 16-bit word:
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* Transmit 8-bit offset, and read 16bits
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*/
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mutex_lock(port_mutex + port);
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*data = 0;
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/* Transmit the offset address to the slave; leave the master in
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* transmit state. */
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LM4_I2C_MSA(port) = slave_addr & 0xff;
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LM4_I2C_MDR(port) = offset & 0xff;
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LM4_I2C_MCS(port) = 0x03;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Send repeated start followed by receive */
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LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x01;
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LM4_I2C_MCS(port) = 0x0b;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Read the first byte */
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d = LM4_I2C_MDR(port) & 0xff;
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/* Issue another read and then a stop. */
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LM4_I2C_MCS(port) = 0x05;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Read the second byte */
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if (slave_addr & I2C_FLAG_BIG_ENDIAN)
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*data = (d << 8) | (LM4_I2C_MDR(port) & 0xff);
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else
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*data = ((LM4_I2C_MDR(port) & 0xff) << 8) | d;
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rv = i2c_transmit_receive(port, slave_addr, ®, 1, buf, 2,
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START, STOP);
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mutex_unlock(port_mutex + port);
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if (rv)
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return rv;
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if (slave_addr & I2C_FLAG_BIG_ENDIAN)
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*data = ((int)buf[0] << 8) | buf[1];
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else
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*data = ((int)buf[1] << 8) | buf[0];
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return EC_SUCCESS;
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}
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@@ -104,113 +172,93 @@ int i2c_read16(int port, int slave_addr, int offset, int* data)
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int i2c_write16(int port, int slave_addr, int offset, int data)
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{
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int rv;
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uint8_t buf[3];
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buf[0] = offset & 0xff;
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if (slave_addr & I2C_FLAG_BIG_ENDIAN) {
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buf[1] = (data >> 8) & 0xff;
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buf[2] = data & 0xff;
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} else {
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buf[1] = data & 0xff;
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buf[2] = (data >> 8) & 0xff;
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}
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mutex_lock(port_mutex + port);
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/* Transmit the offset address to the slave; leave the master in
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* transmit state. */
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LM4_I2C_MDR(port) = offset & 0xff;
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LM4_I2C_MSA(port) = slave_addr & 0xff;
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LM4_I2C_MCS(port) = 0x03;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Transmit the first byte */
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if (slave_addr & I2C_FLAG_BIG_ENDIAN)
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LM4_I2C_MDR(port) = (data >> 8) & 0xff;
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else
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LM4_I2C_MDR(port) = data & 0xff;
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LM4_I2C_MCS(port) = 0x01;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Transmit the second byte and then a stop */
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if (slave_addr & I2C_FLAG_BIG_ENDIAN)
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LM4_I2C_MDR(port) = data & 0xff;
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else
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LM4_I2C_MDR(port) = (data >> 8) & 0xff;
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LM4_I2C_MCS(port) = 0x05;
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rv = i2c_transmit_receive(port, slave_addr, buf, 3, 0, 0,
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START, STOP);
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mutex_unlock(port_mutex + port);
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return wait_idle(port);
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}
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/* TODO:(crosbug.com/p/8026) combine common functions to save space */
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return rv;
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}
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int i2c_read8(int port, int slave_addr, int offset, int* data)
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{
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int rv;
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uint8_t reg, val;
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reg = offset;
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mutex_lock(port_mutex + port);
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*data = 0;
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/* Transmit the offset address to the slave; leave the master in
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* transmit state. */
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LM4_I2C_MSA(port) = slave_addr & 0xff;
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LM4_I2C_MDR(port) = offset & 0xff;
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LM4_I2C_MCS(port) = 0x03;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Send repeated start followed by receive and stop */
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LM4_I2C_MSA(port) = (slave_addr & 0xff) | 0x01;
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LM4_I2C_MCS(port) = 0x07; /* NOTE: datasheet suggests 0x0b, but
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* 0x07 with the change in direction
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* flips it to a RECEIVE and STOP.
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* I think.
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*/
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Read the byte */
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*data = LM4_I2C_MDR(port) & 0xff;
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rv = i2c_transmit_receive(port, slave_addr, ®, 1, &val, 1,
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START, STOP);
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mutex_unlock(port_mutex + port);
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return EC_SUCCESS;
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if (!rv)
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*data = val;
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return rv;
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}
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int i2c_write8(int port, int slave_addr, int offset, int data)
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{
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int rv;
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uint8_t buf[2];
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buf[0] = offset;
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buf[1] = data;
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mutex_lock(port_mutex + port);
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rv = i2c_transmit_receive(port, slave_addr, buf, 2, 0, 0,
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START, STOP);
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mutex_unlock(port_mutex + port);
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return rv;
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}
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/* Read ascii string using smbus read block protocol.
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* The return data <data> will be null terminated.
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*/
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int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
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int len)
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{
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int rv;
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uint8_t reg, block_length;
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mutex_lock(port_mutex + port);
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/* Transmit the offset address to the slave; leave the master in
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* transmit state. */
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LM4_I2C_MDR(port) = offset & 0xff;
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LM4_I2C_MSA(port) = slave_addr & 0xff;
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LM4_I2C_MCS(port) = 0x03;
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reg = offset;
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/* Send device reg space offset, and read back block length.
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* Keep this session open without a stop
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*/
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rv = i2c_transmit_receive(port, slave_addr, ®, 1, &block_length, 1,
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START, NO_STOP);
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if (rv)
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goto exit;
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rv = wait_idle(port);
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if (rv) {
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mutex_unlock(port_mutex + port);
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return rv;
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}
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if (len && block_length > (len - 1))
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block_length = len - 1;
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/* Send repeated start followed by transmit and stop */
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LM4_I2C_MDR(port) = data & 0xff;
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LM4_I2C_MCS(port) = 0x05;
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rv = i2c_transmit_receive(port, slave_addr, 0, 0, data, block_length,
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NO_START, STOP);
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data[block_length] = 0;
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exit:
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mutex_unlock(port_mutex + port);
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return wait_idle(port);
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return rv;
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}
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/*****************************************************************************/
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/* Interrupt handlers */
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@@ -265,7 +313,7 @@ static void scan_bus(int port, char *desc)
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rv = wait_idle(port);
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if (rv == EC_SUCCESS)
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uart_printf("\nFound device at 8-bit addr 0x%02x\n", a);
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}
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}
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mutex_unlock(port_mutex + port);
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@@ -36,4 +36,16 @@ int i2c_read8(int port, int slave_addr, int offset, int* data);
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* space. */
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int i2c_write8(int port, int slave_addr, int offset, int data);
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/* Read ascii string using smbus read block protocol.
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* Read bytestream from <slaveaddr>:<offset> with format:
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* [length_N] [byte_0] [byte_1] ... [byte_N-1]
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*
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* <len> : the max length of receving buffer. to read N bytes
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* ascii, len should be at least N+1 to include the
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* terminating 0.
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* <len> == 0 : buffer size > 255
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*/
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int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
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int len);
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#endif /* __CROS_EC_I2C_H */
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