--- /dev/null
+/* This file contains device independent i2c device driver helpers. */
+
+#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;
+}