Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 415 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
new file mode 100644
index 0000000000..138c3f5e00
--- /dev/null
+++ b/drivers/i2c/i2c-smbus.c
@@ -0,0 +1,415 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * i2c-smbus.c - SMBus extensions to the I2C protocol
+ *
+ * Copyright (C) 2008 David Brownell
+ * Copyright (C) 2010-2019 Jean Delvare <jdelvare@suse.de>
+ */
+
+#include <linux/device.h>
+#include <linux/dmi.h>
+#include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+struct i2c_smbus_alert {
+	struct work_struct	alert;
+	struct i2c_client	*ara;		/* Alert response address */
+};
+
+struct alert_data {
+	unsigned short		addr;
+	enum i2c_alert_protocol	type;
+	unsigned int		data;
+};
+
+/* If this is the alerting device, notify its driver */
+static int smbus_do_alert(struct device *dev, void *addrp)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct alert_data *data = addrp;
+	struct i2c_driver *driver;
+
+	if (!client || client->addr != data->addr)
+		return 0;
+	if (client->flags & I2C_CLIENT_TEN)
+		return 0;
+
+	/*
+	 * Drivers should either disable alerts, or provide at least
+	 * a minimal handler.  Lock so the driver won't change.
+	 */
+	device_lock(dev);
+	if (client->dev.driver) {
+		driver = to_i2c_driver(client->dev.driver);
+		if (driver->alert)
+			driver->alert(client, data->type, data->data);
+		else
+			dev_warn(&client->dev, "no driver alert()!\n");
+	} else
+		dev_dbg(&client->dev, "alert with no driver\n");
+	device_unlock(dev);
+
+	/* Stop iterating after we find the device */
+	return -EBUSY;
+}
+
+/*
+ * The alert IRQ handler needs to hand work off to a task which can issue
+ * SMBus calls, because those sleeping calls can't be made in IRQ context.
+ */
+static irqreturn_t smbus_alert(int irq, void *d)
+{
+	struct i2c_smbus_alert *alert = d;
+	struct i2c_client *ara;
+
+	ara = alert->ara;
+
+	for (;;) {
+		s32 status;
+		struct alert_data data;
+
+		/*
+		 * Devices with pending alerts reply in address order, low
+		 * to high, because of slave transmit arbitration.  After
+		 * responding, an SMBus device stops asserting SMBALERT#.
+		 *
+		 * Note that SMBus 2.0 reserves 10-bit addresses for future
+		 * use.  We neither handle them, nor try to use PEC here.
+		 */
+		status = i2c_smbus_read_byte(ara);
+		if (status < 0)
+			break;
+
+		data.data = status & 1;
+		data.addr = status >> 1;
+		data.type = I2C_PROTOCOL_SMBUS_ALERT;
+
+		dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
+			data.addr, data.data);
+
+		/* Notify driver for the device which issued the alert */
+		device_for_each_child(&ara->adapter->dev, &data,
+				      smbus_do_alert);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void smbalert_work(struct work_struct *work)
+{
+	struct i2c_smbus_alert *alert;
+
+	alert = container_of(work, struct i2c_smbus_alert, alert);
+
+	smbus_alert(0, alert);
+
+}
+
+/* Setup SMBALERT# infrastructure */
+static int smbalert_probe(struct i2c_client *ara)
+{
+	struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
+	struct i2c_smbus_alert *alert;
+	struct i2c_adapter *adapter = ara->adapter;
+	int res, irq;
+
+	alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
+			     GFP_KERNEL);
+	if (!alert)
+		return -ENOMEM;
+
+	if (setup) {
+		irq = setup->irq;
+	} else {
+		irq = fwnode_irq_get_byname(dev_fwnode(adapter->dev.parent),
+					    "smbus_alert");
+		if (irq <= 0)
+			return irq;
+	}
+
+	INIT_WORK(&alert->alert, smbalert_work);
+	alert->ara = ara;
+
+	if (irq > 0) {
+		res = devm_request_threaded_irq(&ara->dev, irq,
+						NULL, smbus_alert,
+						IRQF_SHARED | IRQF_ONESHOT,
+						"smbus_alert", alert);
+		if (res)
+			return res;
+	}
+
+	i2c_set_clientdata(ara, alert);
+	dev_info(&adapter->dev, "supports SMBALERT#\n");
+
+	return 0;
+}
+
+/* IRQ and memory resources are managed so they are freed automatically */
+static void smbalert_remove(struct i2c_client *ara)
+{
+	struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
+
+	cancel_work_sync(&alert->alert);
+}
+
+static const struct i2c_device_id smbalert_ids[] = {
+	{ "smbus_alert", 0 },
+	{ /* LIST END */ }
+};
+MODULE_DEVICE_TABLE(i2c, smbalert_ids);
+
+static struct i2c_driver smbalert_driver = {
+	.driver = {
+		.name	= "smbus_alert",
+	},
+	.probe		= smbalert_probe,
+	.remove		= smbalert_remove,
+	.id_table	= smbalert_ids,
+};
+
+/**
+ * i2c_handle_smbus_alert - Handle an SMBus alert
+ * @ara: the ARA client on the relevant adapter
+ * Context: can't sleep
+ *
+ * Helper function to be called from an I2C bus driver's interrupt
+ * handler. It will schedule the alert work, in turn calling the
+ * corresponding I2C device driver's alert function.
+ *
+ * It is assumed that ara is a valid i2c client previously returned by
+ * i2c_new_smbus_alert_device().
+ */
+int i2c_handle_smbus_alert(struct i2c_client *ara)
+{
+	struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
+
+	return schedule_work(&alert->alert);
+}
+EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
+
+module_i2c_driver(smbalert_driver);
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+#define SMBUS_HOST_NOTIFY_LEN	3
+struct i2c_slave_host_notify_status {
+	u8 index;
+	u8 addr;
+};
+
+static int i2c_slave_host_notify_cb(struct i2c_client *client,
+				    enum i2c_slave_event event, u8 *val)
+{
+	struct i2c_slave_host_notify_status *status = client->dev.platform_data;
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_RECEIVED:
+		/* We only retrieve the first byte received (addr)
+		 * since there is currently no support to retrieve the data
+		 * parameter from the client.
+		 */
+		if (status->index == 0)
+			status->addr = *val;
+		if (status->index < U8_MAX)
+			status->index++;
+		break;
+	case I2C_SLAVE_STOP:
+		if (status->index == SMBUS_HOST_NOTIFY_LEN)
+			i2c_handle_smbus_host_notify(client->adapter,
+						     status->addr);
+		fallthrough;
+	case I2C_SLAVE_WRITE_REQUESTED:
+		status->index = 0;
+		break;
+	case I2C_SLAVE_READ_REQUESTED:
+	case I2C_SLAVE_READ_PROCESSED:
+		*val = 0xff;
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
+ * @adapter: the target adapter
+ * Context: can sleep
+ *
+ * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
+ *
+ * Handling is done by creating a device and its callback and handling data
+ * received via the SMBus host-notify address (0x8)
+ *
+ * This returns the client, which should be ultimately freed using
+ * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
+ */
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+	struct i2c_board_info host_notify_board_info = {
+		I2C_BOARD_INFO("smbus_host_notify", 0x08),
+		.flags  = I2C_CLIENT_SLAVE,
+	};
+	struct i2c_slave_host_notify_status *status;
+	struct i2c_client *client;
+	int ret;
+
+	status = kzalloc(sizeof(struct i2c_slave_host_notify_status),
+			 GFP_KERNEL);
+	if (!status)
+		return ERR_PTR(-ENOMEM);
+
+	host_notify_board_info.platform_data = status;
+
+	client = i2c_new_client_device(adapter, &host_notify_board_info);
+	if (IS_ERR(client)) {
+		kfree(status);
+		return client;
+	}
+
+	ret = i2c_slave_register(client, i2c_slave_host_notify_cb);
+	if (ret) {
+		i2c_unregister_device(client);
+		kfree(status);
+		return ERR_PTR(ret);
+	}
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device);
+
+/**
+ * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
+ * support
+ * @client: the client to free
+ * Context: can sleep
+ *
+ * Free the i2c_client allocated via i2c_new_slave_host_notify_device
+ */
+void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+	if (IS_ERR_OR_NULL(client))
+		return;
+
+	i2c_slave_unregister(client);
+	kfree(client->dev.platform_data);
+	i2c_unregister_device(client);
+}
+EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
+#endif
+
+/*
+ * SPD is not part of SMBus but we include it here for convenience as the
+ * target systems are the same.
+ * Restrictions to automatic SPD instantiation:
+ *  - Only works if all filled slots have the same memory type
+ *  - Only works for DDR2, DDR3 and DDR4 for now
+ *  - Only works on systems with 1 to 4 memory slots
+ */
+#if IS_ENABLED(CONFIG_DMI)
+void i2c_register_spd(struct i2c_adapter *adap)
+{
+	int n, slot_count = 0, dimm_count = 0;
+	u16 handle;
+	u8 common_mem_type = 0x0, mem_type;
+	u64 mem_size;
+	const char *name;
+
+	while ((handle = dmi_memdev_handle(slot_count)) != 0xffff) {
+		slot_count++;
+
+		/* Skip empty slots */
+		mem_size = dmi_memdev_size(handle);
+		if (!mem_size)
+			continue;
+
+		/* Skip undefined memory type */
+		mem_type = dmi_memdev_type(handle);
+		if (mem_type <= 0x02)		/* Invalid, Other, Unknown */
+			continue;
+
+		if (!common_mem_type) {
+			/* First filled slot */
+			common_mem_type = mem_type;
+		} else {
+			/* Check that all filled slots have the same type */
+			if (mem_type != common_mem_type) {
+				dev_warn(&adap->dev,
+					 "Different memory types mixed, not instantiating SPD\n");
+				return;
+			}
+		}
+		dimm_count++;
+	}
+
+	/* No useful DMI data, bail out */
+	if (!dimm_count)
+		return;
+
+	dev_info(&adap->dev, "%d/%d memory slots populated (from DMI)\n",
+		 dimm_count, slot_count);
+
+	if (slot_count > 4) {
+		dev_warn(&adap->dev,
+			 "Systems with more than 4 memory slots not supported yet, not instantiating SPD\n");
+		return;
+	}
+
+	/*
+	 * Memory types could be found at section 7.18.2 (Memory Device — Type), table 78
+	 * https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
+	 */
+	switch (common_mem_type) {
+	case 0x12:	/* DDR */
+	case 0x13:	/* DDR2 */
+	case 0x18:	/* DDR3 */
+	case 0x1B:	/* LPDDR */
+	case 0x1C:	/* LPDDR2 */
+	case 0x1D:	/* LPDDR3 */
+		name = "spd";
+		break;
+	case 0x1A:	/* DDR4 */
+	case 0x1E:	/* LPDDR4 */
+		name = "ee1004";
+		break;
+	default:
+		dev_info(&adap->dev,
+			 "Memory type 0x%02x not supported yet, not instantiating SPD\n",
+			 common_mem_type);
+		return;
+	}
+
+	/*
+	 * We don't know in which slots the memory modules are. We could
+	 * try to guess from the slot names, but that would be rather complex
+	 * and unreliable, so better probe all possible addresses until we
+	 * have found all memory modules.
+	 */
+	for (n = 0; n < slot_count && dimm_count; n++) {
+		struct i2c_board_info info;
+		unsigned short addr_list[2];
+
+		memset(&info, 0, sizeof(struct i2c_board_info));
+		strscpy(info.type, name, I2C_NAME_SIZE);
+		addr_list[0] = 0x50 + n;
+		addr_list[1] = I2C_CLIENT_END;
+
+		if (!IS_ERR(i2c_new_scanned_device(adap, &info, addr_list, NULL))) {
+			dev_info(&adap->dev,
+				 "Successfully instantiated SPD at 0x%hx\n",
+				 addr_list[0]);
+			dimm_count--;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(i2c_register_spd);
+#endif
+
+MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
+MODULE_DESCRIPTION("SMBus protocol extensions support");
+MODULE_LICENSE("GPL");