minix/lib/libi2cdriver/i2cdriver.c
Thomas Cort 75bd3009d3 libi2cdriver: add functions for IC register access
Many i2c device drivers used similar code to access registers on
the ICs they drive. This commit implements that functionality in
libi2cdriver and updates the drivers to use the library instead of
their own register access functions. The net result is 375+ fewer
lines of code and less work for people developing new drivers.

The two exceptions were cat24c256 and parts of tda19988. They access
the bus in uncommon ways. It doesn't make sense at this time to
move their read/write functions into libi2cdriver.

Change-Id: Id8280b71af33b710a49944d7f20a7262be9f5988
2013-09-18 08:10:26 -04:00

367 lines
7.1 KiB
C

/* This file contains device independent i2c device driver helpers. */
#include <assert.h>
#include <minix/drivers.h>
#include <minix/endpoint.h>
#include <minix/i2c.h>
#include <minix/i2cdriver.h>
#include <minix/ipc.h>
#include <minix/ds.h>
void
i2cdriver_announce(uint32_t bus)
{
/* Announce we are up after a fresh start or restart. */
int r;
char key[DS_MAX_KEYLEN];
char label[DS_MAX_KEYLEN];
char *driver_prefix = "drv.i2c.";
/* Callers are allowed to use sendrec to communicate with drivers.
* For this reason, there may blocked callers when a driver restarts.
* Ask the kernel to unblock them (if any).
*/
#if USE_STATECTL
if ((r = sys_statectl(SYS_STATE_CLEAR_IPC_REFS)) != OK) {
panic("chardriver_init: sys_statectl failed: %d", r);
}
#endif
/* Publish a driver up event. */
r = ds_retrieve_label_name(label, getprocnr());
if (r != OK) {
panic("unable to get own label: %d\n", r);
}
/* example key: drv.i2c.1.cat24c245.0x50 */
snprintf(key, DS_MAX_KEYLEN, "%s%d.%s", driver_prefix, bus, label);
r = ds_publish_u32(key, DS_DRIVER_UP, DSF_OVERWRITE);
if (r != OK) {
panic("unable to publish driver up event: %d\n", r);
}
}
int
i2cdriver_env_parse(uint32_t * bus, i2c_addr_t * address,
i2c_addr_t * valid_addrs)
{
/* fill in bus and address with the values passed on the command line */
int r;
int found;
long int busl;
long int addressl;
r = env_parse("bus", "d", 0, &busl, 1, 3);
if (r != EP_SET) {
return -1;
}
*bus = (uint32_t) busl;
r = env_parse("address", "x", 0, &addressl, 0x0000, 0x03ff);
if (r != EP_SET) {
return -1;
}
*address = addressl;
found = 0;
while (*valid_addrs != 0x0000) {
if (*address == *valid_addrs) {
found = 1;
break;
}
valid_addrs++;
}
if (!found) {
return 1;
}
return 0;
}
endpoint_t
i2cdriver_bus_endpoint(uint32_t bus)
{
/* locate the driver for the i2c bus itself */
int r;
char *label_prefix = "i2c.";
char label[DS_MAX_KEYLEN];
endpoint_t bus_endpoint;
snprintf(label, DS_MAX_KEYLEN, "%s%d", label_prefix, bus);
r = ds_retrieve_label_endpt(label, &bus_endpoint);
if (r != OK) {
return 0;
}
return bus_endpoint;
}
int
i2cdriver_subscribe_bus_updates(uint32_t bus)
{
int r;
char regex[DS_MAX_KEYLEN];
/* only capture events for the specified bus */
snprintf(regex, DS_MAX_KEYLEN, "drv\\.chr\\.i2c\\.%d", bus);
/* Subscribe to driver events from the i2c bus */
r = ds_subscribe(regex, DSF_INITIAL | DSF_OVERWRITE);
if (r != OK) {
return r;
}
return OK;
}
void
i2cdriver_handle_bus_update(endpoint_t * bus_endpoint, uint32_t bus,
i2c_addr_t address)
{
char key[DS_MAX_KEYLEN];
u32_t value;
int type;
endpoint_t owner_endpoint, old_endpoint;
int r;
/* check for pending events */
while ((r = ds_check(key, &type, &owner_endpoint)) == OK) {
r = ds_retrieve_u32(key, &value);
if (r != OK) {
return;
}
if (value == DS_DRIVER_UP) {
old_endpoint = *bus_endpoint;
/* look up the bus's (potentially new) endpoint */
*bus_endpoint = i2cdriver_bus_endpoint(bus);
/* was updated endpoint? */
if (old_endpoint != *bus_endpoint) {
/* re-reserve device to allow the driver to
* continue working, even through a manual
* down/up.
*/
i2cdriver_reserve_device(*bus_endpoint,
address);
}
}
}
}
int
i2cdriver_reserve_device(endpoint_t bus_endpoint, i2c_addr_t address)
{
int r;
message m;
m.m_type = BUSC_I2C_RESERVE;
m.DEVICE = address;
r = sendrec(bus_endpoint, &m);
if (r != OK) {
return EIO;
}
return m.REP_STATUS; /* return reply code OK, EBUSY, EINVAL, etc. */
}
int
i2cdriver_exec(endpoint_t bus_endpoint, minix_i2c_ioctl_exec_t * ioctl_exec)
{
int r;
message m;
cp_grant_id_t grant_nr;
grant_nr = cpf_grant_direct(bus_endpoint, (vir_bytes) ioctl_exec,
sizeof(minix_i2c_ioctl_exec_t), CPF_READ | CPF_WRITE);
memset(&m, '\0', sizeof(message));
m.m_type = BUSC_I2C_EXEC;
m.IO_GRANT = (char *) grant_nr;
r = sendrec(bus_endpoint, &m);
cpf_revoke(grant_nr);
if (r != OK) {
return EIO;
}
return m.REP_STATUS;
}
static int
__i2creg_read(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t raw,
uint8_t reg, uint32_t * val, size_t vallen)
{
int r, i;
minix_i2c_ioctl_exec_t ioctl_exec;
assert(val != NULL);
assert(vallen >= 1 && vallen <= 4);
memset(&ioctl_exec, '\0', sizeof(minix_i2c_ioctl_exec_t));
/* Read from chip */
ioctl_exec.iie_op = I2C_OP_READ_WITH_STOP;
ioctl_exec.iie_addr = address;
if (!raw) {
/* write the register address */
ioctl_exec.iie_cmd[0] = reg;
ioctl_exec.iie_cmdlen = 1;
}
/* read vallen bytes */
ioctl_exec.iie_buflen = vallen;
r = i2cdriver_exec(bus_endpoint, &ioctl_exec);
if (r != OK) {
return -1;
}
for (*val = 0, i = 0; i < vallen; i++) {
*val = ((*val) << 8) | ioctl_exec.iie_buf[i];
}
return OK;
}
int
i2creg_raw_read8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t * val)
{
int r;
uint32_t val32;
r = __i2creg_read(bus_endpoint, address, 1, 0, &val32, 1);
*val = val32 & 0xff;
return r;
}
int
i2creg_read8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint8_t * val)
{
int r;
uint32_t val32;
r = __i2creg_read(bus_endpoint, address, 0, reg, &val32, 1);
*val = val32 & 0xff;
return r;
}
int
i2creg_read16(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint16_t * val)
{
int r;
uint32_t val32;
r = __i2creg_read(bus_endpoint, address, 0, reg, &val32, 2);
*val = val32 & 0xffff;
return r;
}
int
i2creg_read24(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint32_t * val)
{
return __i2creg_read(bus_endpoint, address, 0, reg, val, 3);
}
static int
__i2creg_write(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t raw,
uint8_t reg, uint8_t val)
{
int r;
minix_i2c_ioctl_exec_t ioctl_exec;
memset(&ioctl_exec, '\0', sizeof(minix_i2c_ioctl_exec_t));
/* Write to chip */
ioctl_exec.iie_op = I2C_OP_WRITE_WITH_STOP;
ioctl_exec.iie_addr = address;
if (raw) {
/* write just the value */
ioctl_exec.iie_buf[0] = val;
ioctl_exec.iie_buflen = 1;
} else {
/* write the register address and value */
ioctl_exec.iie_buf[0] = reg;
ioctl_exec.iie_buf[1] = val;
ioctl_exec.iie_buflen = 2;
}
r = i2cdriver_exec(bus_endpoint, &ioctl_exec);
if (r != OK) {
return -1;
}
return OK;
}
int
i2creg_write8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint8_t val)
{
return __i2creg_write(bus_endpoint, address, 0, reg, val);
}
int
i2creg_raw_write8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t val)
{
return __i2creg_write(bus_endpoint, address, 1, 0, val);
}
int
i2creg_set_bits8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint8_t bits)
{
int r;
uint8_t val;
r = i2creg_read8(bus_endpoint, address, reg, &val);
if (r != OK) {
return -1;
}
val |= bits;
r = i2creg_write8(bus_endpoint, address, reg, val);
if (r != OK) {
return -1;
}
return OK;
}
int
i2creg_clear_bits8(endpoint_t bus_endpoint, i2c_addr_t address, uint8_t reg,
uint8_t bits)
{
int r;
uint8_t val;
r = i2creg_read8(bus_endpoint, address, reg, &val);
if (r != OK) {
return -1;
}
val &= ~bits;
r = i2creg_write8(bus_endpoint, address, reg, val);
if (r != OK) {
return -1;
}
return OK;
}