libi2cdriver: library for i2c device drivers

Change-Id: Ib6d5617e4b62e0bc5b25e6fa92b44baf536b1961

distrib/sets/lists/minix/md.evbarm

@@ -97,6 +97,8 @@
 ./usr/lib/libclkconf_pic.a		minix-sys
 ./usr/lib/libgpio.a			minix-sys
 ./usr/lib/libgpio_pic.a			minix-sys
+./usr/lib/libi2cdriver.a		minix-sys
+./usr/lib/libi2cdriver_pic.a		minix-sys
 ./usr/lib/libpadconf.a			minix-sys
 ./usr/lib/libpadconf_pic.a		minix-sys
 ./usr/mdec				minix-sys

distrib/sets/lists/minix/mi

@@ -1073,6 +1073,7 @@
 ./usr/include/minix/hash.h		minix-sys
 ./usr/include/minix/hgfs.h		minix-sys
 ./usr/include/minix/i2c.h		minix-sys
+./usr/include/minix/i2cdriver.h		minix-sys
 ./usr/include/minix/input.h		minix-sys
 ./usr/include/minix/ioctl.h		minix-sys
 ./usr/include/minix/ipcconst.h		minix-sys

include/minix/Makefile

@@ -11,7 +11,7 @@ INCS+=	acpi.h audio_fw.h bitmap.h \
 	debug.h devio.h devman.h dmap.h \
 	driver.h drivers.h drvlib.h ds.h \
 	endpoint.h fb.h fslib.h gpio.h gcov.h hash.h \
-	hgfs.h i2c.h ioctl.h input.h ipc.h ipcconst.h \
+	hgfs.h i2c.h i2cdriver.h ioctl.h input.h ipc.h ipcconst.h \
 	keymap.h log.h mmio.h mount.h mthread.h minlib.h \
 	netdriver.h optset.h padconf.h partition.h portio.h \
 	priv.h procfs.h profile.h queryparam.h \

include/minix/i2cdriver.h

@@ -0,0 +1,21 @@
+/* Prototypes and definitions for i2c drivers. */
+
+#ifndef _MINIX_I2CDRIVER_H
+#define _MINIX_I2CDRIVER_H
+
+#include <minix/endpoint.h>
+#include <minix/i2c.h>
+#include <minix/ipc.h>
+
+/* Functions defined by i2cdriver.c: */
+int i2cdriver_env_parse(uint32_t * bus, i2c_addr_t * address,
+						i2c_addr_t * valid_addrs);
+void i2cdriver_announce(uint32_t bus);
+endpoint_t i2cdriver_bus_endpoint(uint32_t bus);
+int i2cdriver_subscribe_bus_updates(uint32_t bus);
+void i2cdriver_handle_bus_update(endpoint_t * bus_endpoint, uint32_t bus,
+							i2c_addr_t address);
+int i2cdriver_reserve_device(endpoint_t bus_endpoint, i2c_addr_t address);
+int i2cdriver_exec(endpoint_t bus_endpoint, minix_i2c_ioctl_exec_t *ioctl_exec);
+
+#endif /* _MINIX_I2CDRIVER_H */

lib/Makefile

@@ -54,7 +54,7 @@ SUBDIR += libvassert libhgfs libvboxfs libvirtio
 .endif
 
 .if (${MACHINE_ARCH} == "earm")
-SUBDIR += libclkconf libgpio libpadconf
+SUBDIR += libclkconf libgpio libi2cdriver libpadconf
 .endif
 
 .if (${MKRUMP} != "no")

lib/libi2cdriver/Makefile

@@ -0,0 +1,7 @@
+# Makefile for libi2cdriver
+
+LIB=	i2cdriver
+
+SRCS=	i2cdriver.c
+
+.include <bsd.lib.mk>

lib/libi2cdriver/i2cdriver.c

@@ -0,0 +1,195 @@
+/* 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;
+}