low_i2c.c

linux内核源码

	psteps = of_get_property(np, "AAPL,address-step", NULL);
	steps = psteps ? (*psteps) : 0x10;
	for (host->bsteps = 0; (steps & 0x01) == 0; host->bsteps++)
		steps >>= 1;
	/* Select interface rate */
	host->speed = KW_I2C_MODE_25KHZ;
	prate = of_get_property(np, "AAPL,i2c-rate", NULL);
	if (prate) switch(*prate) {
	case 100:
		host->speed = KW_I2C_MODE_100KHZ;
		break;
	case 50:
		host->speed = KW_I2C_MODE_50KHZ;
		break;
	case 25:
		host->speed = KW_I2C_MODE_25KHZ;
		break;
	}	
	host->irq = irq_of_parse_and_map(np, 0);
	if (host->irq == NO_IRQ)
		printk(KERN_WARNING
		       "low_i2c: Failed to map interrupt for %s\n",
		       np->full_name);

	host->base = ioremap((*addrp), 0x1000);
	if (host->base == NULL) {
		printk(KERN_ERR "low_i2c: Can't map registers for %s\n",
		       np->full_name);
		kfree(host);
		return NULL;
	}

	/* Make sure IRQ is disabled */
	kw_write_reg(reg_ier, 0);

	/* Request chip interrupt */
	if (request_irq(host->irq, kw_i2c_irq, 0, "keywest i2c", host))
		host->irq = NO_IRQ;

	printk(KERN_INFO "KeyWest i2c @0x%08x irq %d %s\n",
	       *addrp, host->irq, np->full_name);

	return host;
}


static void __init kw_i2c_add(struct pmac_i2c_host_kw *host,
			      struct device_node *controller,
			      struct device_node *busnode,
			      int channel)
{
	struct pmac_i2c_bus *bus;

	bus = kzalloc(sizeof(struct pmac_i2c_bus), GFP_KERNEL);
	if (bus == NULL)
		return;

	bus->controller = of_node_get(controller);
	bus->busnode = of_node_get(busnode);
	bus->type = pmac_i2c_bus_keywest;
	bus->hostdata = host;
	bus->channel = channel;
	bus->mode = pmac_i2c_mode_std;
	bus->open = kw_i2c_open;
	bus->close = kw_i2c_close;
	bus->xfer = kw_i2c_xfer;
	mutex_init(&bus->mutex);
	if (controller == busnode)
		bus->flags = pmac_i2c_multibus;
	list_add(&bus->link, &pmac_i2c_busses);

	printk(KERN_INFO " channel %d bus %s\n", channel,
	       (controller == busnode) ? "<multibus>" : busnode->full_name);
}

static void __init kw_i2c_probe(void)
{
	struct device_node *np, *child, *parent;

	/* Probe keywest-i2c busses */
	for (np = NULL;
	     (np = of_find_compatible_node(np, "i2c","keywest-i2c")) != NULL;){
		struct pmac_i2c_host_kw *host;
		int multibus, chans, i;

		/* Found one, init a host structure */
		host = kw_i2c_host_init(np);
		if (host == NULL)
			continue;

		/* Now check if we have a multibus setup (old style) or if we
		 * have proper bus nodes. Note that the "new" way (proper bus
		 * nodes) might cause us to not create some busses that are
		 * kept hidden in the device-tree. In the future, we might
		 * want to work around that by creating busses without a node
		 * but not for now
		 */
		child = of_get_next_child(np, NULL);
		multibus = !child || strcmp(child->name, "i2c-bus");
		of_node_put(child);

		/* For a multibus setup, we get the bus count based on the
		 * parent type
		 */
		if (multibus) {
			parent = of_get_parent(np);
			if (parent == NULL)
				continue;
			chans = parent->name[0] == 'u' ? 2 : 1;
			for (i = 0; i < chans; i++)
				kw_i2c_add(host, np, np, i);
		} else {
			for (child = NULL;
			     (child = of_get_next_child(np, child)) != NULL;) {
				const u32 *reg = of_get_property(child,
						"reg", NULL);
				if (reg == NULL)
					continue;
				kw_i2c_add(host, np, child, *reg);
			}
		}
	}
}


/*
 *
 * PMU implementation
 *
 */

#ifdef CONFIG_ADB_PMU

/*
 * i2c command block to the PMU
 */
struct pmu_i2c_hdr {
	u8	bus;
	u8	mode;
	u8	bus2;
	u8	address;
	u8	sub_addr;
	u8	comb_addr;
	u8	count;
	u8	data[];
};

static void pmu_i2c_complete(struct adb_request *req)
{
	complete(req->arg);
}

static int pmu_i2c_xfer(struct pmac_i2c_bus *bus, u8 addrdir, int subsize,
			u32 subaddr, u8 *data, int len)
{
	struct adb_request *req = bus->hostdata;
	struct pmu_i2c_hdr *hdr = (struct pmu_i2c_hdr *)&req->data[1];
	struct completion comp;
	int read = addrdir & 1;
	int retry;
	int rc = 0;

	/* For now, limit ourselves to 16 bytes transfers */
	if (len > 16)
		return -EINVAL;

	init_completion(&comp);

	for (retry = 0; retry < 16; retry++) {
		memset(req, 0, sizeof(struct adb_request));
		hdr->bus = bus->channel;
		hdr->count = len;

		switch(bus->mode) {
		case pmac_i2c_mode_std:
			if (subsize != 0)
				return -EINVAL;
			hdr->address = addrdir;
			hdr->mode = PMU_I2C_MODE_SIMPLE;
			break;
		case pmac_i2c_mode_stdsub:
		case pmac_i2c_mode_combined:
			if (subsize != 1)
				return -EINVAL;
			hdr->address = addrdir & 0xfe;
			hdr->comb_addr = addrdir;
			hdr->sub_addr = subaddr;
			if (bus->mode == pmac_i2c_mode_stdsub)
				hdr->mode = PMU_I2C_MODE_STDSUB;
			else
				hdr->mode = PMU_I2C_MODE_COMBINED;
			break;
		default:
			return -EINVAL;
		}

		INIT_COMPLETION(comp);
		req->data[0] = PMU_I2C_CMD;
		req->reply[0] = 0xff;
		req->nbytes = sizeof(struct pmu_i2c_hdr) + 1;
		req->done = pmu_i2c_complete;
		req->arg = &comp;
		if (!read && len) {
			memcpy(hdr->data, data, len);
			req->nbytes += len;
		}
		rc = pmu_queue_request(req);
		if (rc)
			return rc;
		wait_for_completion(&comp);
		if (req->reply[0] == PMU_I2C_STATUS_OK)
			break;
		msleep(15);
	}
	if (req->reply[0] != PMU_I2C_STATUS_OK)
		return -EIO;

	for (retry = 0; retry < 16; retry++) {
		memset(req, 0, sizeof(struct adb_request));

		/* I know that looks like a lot, slow as hell, but darwin
		 * does it so let's be on the safe side for now
		 */
		msleep(15);

		hdr->bus = PMU_I2C_BUS_STATUS;

		INIT_COMPLETION(comp);
		req->data[0] = PMU_I2C_CMD;
		req->reply[0] = 0xff;
		req->nbytes = 2;
		req->done = pmu_i2c_complete;
		req->arg = &comp;
		rc = pmu_queue_request(req);
		if (rc)
			return rc;
		wait_for_completion(&comp);

		if (req->reply[0] == PMU_I2C_STATUS_OK && !read)
			return 0;
		if (req->reply[0] == PMU_I2C_STATUS_DATAREAD && read) {
			int rlen = req->reply_len - 1;

			if (rlen != len) {
				printk(KERN_WARNING "low_i2c: PMU returned %d"
				       " bytes, expected %d !\n", rlen, len);
				return -EIO;
			}
			if (len)
				memcpy(data, &req->reply[1], len);
			return 0;
		}
	}
	return -EIO;
}

static void __init pmu_i2c_probe(void)
{
	struct pmac_i2c_bus *bus;
	struct device_node *busnode;
	int channel, sz;

	if (!pmu_present())
		return;

	/* There might or might not be a "pmu-i2c" node, we use that
	 * or via-pmu itself, whatever we find. I haven't seen a machine
	 * with separate bus nodes, so we assume a multibus setup
	 */
	busnode = of_find_node_by_name(NULL, "pmu-i2c");
	if (busnode == NULL)
		busnode = of_find_node_by_name(NULL, "via-pmu");
	if (busnode == NULL)
		return;

	printk(KERN_INFO "PMU i2c %s\n", busnode->full_name);

	/*
	 * We add bus 1 and 2 only for now, bus 0 is "special"
	 */
	for (channel = 1; channel <= 2; channel++) {
		sz = sizeof(struct pmac_i2c_bus) + sizeof(struct adb_request);
		bus = kzalloc(sz, GFP_KERNEL);
		if (bus == NULL)
			return;

		bus->controller = busnode;
		bus->busnode = busnode;
		bus->type = pmac_i2c_bus_pmu;
		bus->channel = channel;
		bus->mode = pmac_i2c_mode_std;
		bus->hostdata = bus + 1;
		bus->xfer = pmu_i2c_xfer;
		mutex_init(&bus->mutex);
		bus->flags = pmac_i2c_multibus;
		list_add(&bus->link, &pmac_i2c_busses);

		printk(KERN_INFO " channel %d bus <multibus>\n", channel);
	}
}

#endif /* CONFIG_ADB_PMU */


/*
 *
 * SMU implementation
 *
 */

#ifdef CONFIG_PMAC_SMU

static void smu_i2c_complete(struct smu_i2c_cmd *cmd, void *misc)
{
	complete(misc);
}

static int smu_i2c_xfer(struct pmac_i2c_bus *bus, u8 addrdir, int subsize,
			u32 subaddr, u8 *data, int len)
{
	struct smu_i2c_cmd *cmd = bus->hostdata;
	struct completion comp;
	int read = addrdir & 1;
	int rc = 0;

	if ((read && len > SMU_I2C_READ_MAX) ||
	    ((!read) && len > SMU_I2C_WRITE_MAX))
		return -EINVAL;

	memset(cmd, 0, sizeof(struct smu_i2c_cmd));
	cmd->info.bus = bus->channel;
	cmd->info.devaddr = addrdir;
	cmd->info.datalen = len;

	switch(bus->mode) {
	case pmac_i2c_mode_std:
		if (subsize != 0)
			return -EINVAL;
		cmd->info.type = SMU_I2C_TRANSFER_SIMPLE;
		break;
	case pmac_i2c_mode_stdsub:
	case pmac_i2c_mode_combined:
		if (subsize > 3 || subsize < 1)
			return -EINVAL;
		cmd->info.sublen = subsize;
		/* that's big-endian only but heh ! */
		memcpy(&cmd->info.subaddr, ((char *)&subaddr) + (4 - subsize),
		       subsize);
		if (bus->mode == pmac_i2c_mode_stdsub)
			cmd->info.type = SMU_I2C_TRANSFER_STDSUB;
		else
			cmd->info.type = SMU_I2C_TRANSFER_COMBINED;
		break;
	default:
		return -EINVAL;
	}
	if (!read && len)
		memcpy(cmd->info.data, data, len);

	init_completion(&comp);
	cmd->done = smu_i2c_complete;
	cmd->misc = &comp;
	rc = smu_queue_i2c(cmd);
	if (rc < 0)
		return rc;
	wait_for_completion(&comp);
	rc = cmd->status;

	if (read && len)
		memcpy(data, cmd->info.data, len);
	return rc < 0 ? rc : 0;
}

static void __init smu_i2c_probe(void)
{
	struct device_node *controller, *busnode;
	struct pmac_i2c_bus *bus;
	const u32 *reg;
	int sz;

	if (!smu_present())
		return;

	controller = of_find_node_by_name(NULL, "smu-i2c-control");
	if (controller == NULL)
		controller = of_find_node_by_name(NULL, "smu");
	if (controller == NULL)
		return;

	printk(KERN_INFO "SMU i2c %s\n", controller->full_name);

	/* Look for childs, note that they might not be of the right
	 * type as older device trees mix i2c busses and other thigns
	 * at the same level
	 */
	for (busnode = NULL;
	     (busnode = of_get_next_child(controller, busnode)) != NULL;) {
		if (strcmp(busnode->type, "i2c") &&
		    strcmp(busnode->type, "i2c-bus"))
			continue;
		reg = of_get_property(busnode, "reg", NULL);
		if (reg == NULL)
			continue;

		sz = sizeof(struct pmac_i2c_bus) + sizeof(struct smu_i2c_cmd);
		bus = kzalloc(sz, GFP_KERNEL);
		if (bus == NULL)
			return;

		bus->controller = controller;
		bus->busnode = of_node_get(busnode);
		bus->type = pmac_i2c_bus_smu;
		bus->channel = *reg;
		bus->mode = pmac_i2c_mode_std;
		bus->hostdata = bus + 1;
		bus->xfer = smu_i2c_xfer;
		mutex_init(&bus->mutex);
		bus->flags = 0;
		list_add(&bus->link, &pmac_i2c_busses);

		printk(KERN_INFO " channel %x bus %s\n",
		       bus->channel, busnode->full_name);
	}
}

#endif /* CONFIG_PMAC_SMU */

/*
 *
 * Core code
 *
 */


struct pmac_i2c_bus *pmac_i2c_find_bus(struct device_node *node)
{
	struct device_node *p = of_node_get(node);
	struct device_node *prev = NULL;
	struct pmac_i2c_bus *bus;

	while(p) {
		list_for_each_entry(bus, &pmac_i2c_busses, link) {
			if (p == bus->busnode) {
				if (prev && bus->flags & pmac_i2c_multibus) {
					const u32 *reg;
					reg = of_get_property(prev, "reg",
								NULL);
					if (!reg)
						continue;
					if (((*reg) >> 8) != bus->channel)
						continue;
				}
				of_node_put(p);
				of_node_put(prev);
				return bus;
			}
		}
		of_node_put(prev);
		prev = p;
		p = of_get_parent(p);
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(pmac_i2c_find_bus);

u8 pmac_i2c_get_dev_addr(struct device_node *device)
{
	const u32 *reg = of_get_property(device, "reg", NULL);

	if (reg == NULL)
		return 0;

	return (*reg) & 0xff;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_dev_addr);

struct device_node *pmac_i2c_get_controller(struct pmac_i2c_bus *bus)
{
	return bus->controller;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_controller);

struct device_node *pmac_i2c_get_bus_node(struct pmac_i2c_bus *bus)
{
	return bus->busnode;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_bus_node);

int pmac_i2c_get_type(struct pmac_i2c_bus *bus)
{
	return bus->type;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_type);

int pmac_i2c_get_flags(struct pmac_i2c_bus *bus)
{
	return bus->flags;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_flags);

int pmac_i2c_get_channel(struct pmac_i2c_bus *bus)
{
	return bus->channel;
}
EXPORT_SYMBOL_GPL(pmac_i2c_get_channel);