Adding upstream version 5.10.209.upstream/5.10.209upstream

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

1 files changed, 219 insertions, 0 deletions

diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
new file mode 100644
index 000000000..5c7ae421c
--- /dev/null
+++ b/drivers/i2c/i2c-slave-eeprom.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * I2C slave mode EEPROM simulator
+ *
+ * Copyright (C) 2014 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
+ * Copyright (C) 2014 by Renesas Electronics Corporation
+ *
+ * Because most slave IP cores can only detect one I2C slave address anyhow,
+ * this driver does not support simulating EEPROM types which take more than
+ * one address.
+ */
+
+/*
+ * FIXME: What to do if only 8 bits of a 16 bit address are sent?
+ * The ST-M24C64 sends only 0xff then. Needs verification with other
+ * EEPROMs, though. We currently use the 8 bit as a valid address.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/firmware.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/sysfs.h>
+
+struct eeprom_data {
+	struct bin_attribute bin;
+	spinlock_t buffer_lock;
+	u16 buffer_idx;
+	u16 address_mask;
+	u8 num_address_bytes;
+	u8 idx_write_cnt;
+	bool read_only;
+	u8 buffer[];
+};
+
+#define I2C_SLAVE_BYTELEN GENMASK(15, 0)
+#define I2C_SLAVE_FLAG_ADDR16 BIT(16)
+#define I2C_SLAVE_FLAG_RO BIT(17)
+#define I2C_SLAVE_DEVICE_MAGIC(_len, _flags) ((_flags) | ((_len) - 1))
+
+static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
+				     enum i2c_slave_event event, u8 *val)
+{
+	struct eeprom_data *eeprom = i2c_get_clientdata(client);
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_RECEIVED:
+		if (eeprom->idx_write_cnt < eeprom->num_address_bytes) {
+			if (eeprom->idx_write_cnt == 0)
+				eeprom->buffer_idx = 0;
+			eeprom->buffer_idx = *val | (eeprom->buffer_idx << 8);
+			eeprom->idx_write_cnt++;
+		} else {
+			if (!eeprom->read_only) {
+				spin_lock(&eeprom->buffer_lock);
+				eeprom->buffer[eeprom->buffer_idx++ & eeprom->address_mask] = *val;
+				spin_unlock(&eeprom->buffer_lock);
+			}
+		}
+		break;
+
+	case I2C_SLAVE_READ_PROCESSED:
+		/* The previous byte made it to the bus, get next one */
+		eeprom->buffer_idx++;
+		fallthrough;
+	case I2C_SLAVE_READ_REQUESTED:
+		spin_lock(&eeprom->buffer_lock);
+		*val = eeprom->buffer[eeprom->buffer_idx & eeprom->address_mask];
+		spin_unlock(&eeprom->buffer_lock);
+		/*
+		 * Do not increment buffer_idx here, because we don't know if
+		 * this byte will be actually used. Read Linux I2C slave docs
+		 * for details.
+		 */
+		break;
+
+	case I2C_SLAVE_STOP:
+	case I2C_SLAVE_WRITE_REQUESTED:
+		eeprom->idx_write_cnt = 0;
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static ssize_t i2c_slave_eeprom_bin_read(struct file *filp, struct kobject *kobj,
+		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
+{
+	struct eeprom_data *eeprom;
+	unsigned long flags;
+
+	eeprom = dev_get_drvdata(kobj_to_dev(kobj));
+
+	spin_lock_irqsave(&eeprom->buffer_lock, flags);
+	memcpy(buf, &eeprom->buffer[off], count);
+	spin_unlock_irqrestore(&eeprom->buffer_lock, flags);
+
+	return count;
+}
+
+static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kobj,
+		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
+{
+	struct eeprom_data *eeprom;
+	unsigned long flags;
+
+	eeprom = dev_get_drvdata(kobj_to_dev(kobj));
+
+	spin_lock_irqsave(&eeprom->buffer_lock, flags);
+	memcpy(&eeprom->buffer[off], buf, count);
+	spin_unlock_irqrestore(&eeprom->buffer_lock, flags);
+
+	return count;
+}
+
+static int i2c_slave_init_eeprom_data(struct eeprom_data *eeprom, struct i2c_client *client,
+				      unsigned int size)
+{
+	const struct firmware *fw;
+	const char *eeprom_data;
+	int ret = device_property_read_string(&client->dev, "firmware-name", &eeprom_data);
+
+	if (!ret) {
+		ret = request_firmware_into_buf(&fw, eeprom_data, &client->dev,
+						eeprom->buffer, size);
+		if (ret)
+			return ret;
+		release_firmware(fw);
+	} else {
+		/* An empty eeprom typically has all bits set to 1 */
+		memset(eeprom->buffer, 0xff, size);
+	}
+	return 0;
+}
+
+static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct eeprom_data *eeprom;
+	int ret;
+	unsigned int size = FIELD_GET(I2C_SLAVE_BYTELEN, id->driver_data) + 1;
+	unsigned int flag_addr16 = FIELD_GET(I2C_SLAVE_FLAG_ADDR16, id->driver_data);
+
+	eeprom = devm_kzalloc(&client->dev, sizeof(struct eeprom_data) + size, GFP_KERNEL);
+	if (!eeprom)
+		return -ENOMEM;
+
+	eeprom->num_address_bytes = flag_addr16 ? 2 : 1;
+	eeprom->address_mask = size - 1;
+	eeprom->read_only = FIELD_GET(I2C_SLAVE_FLAG_RO, id->driver_data);
+	spin_lock_init(&eeprom->buffer_lock);
+	i2c_set_clientdata(client, eeprom);
+
+	ret = i2c_slave_init_eeprom_data(eeprom, client, size);
+	if (ret)
+		return ret;
+
+	sysfs_bin_attr_init(&eeprom->bin);
+	eeprom->bin.attr.name = "slave-eeprom";
+	eeprom->bin.attr.mode = S_IRUSR | S_IWUSR;
+	eeprom->bin.read = i2c_slave_eeprom_bin_read;
+	eeprom->bin.write = i2c_slave_eeprom_bin_write;
+	eeprom->bin.size = size;
+
+	ret = sysfs_create_bin_file(&client->dev.kobj, &eeprom->bin);
+	if (ret)
+		return ret;
+
+	ret = i2c_slave_register(client, i2c_slave_eeprom_slave_cb);
+	if (ret) {
+		sysfs_remove_bin_file(&client->dev.kobj, &eeprom->bin);
+		return ret;
+	}
+
+	return 0;
+};
+
+static int i2c_slave_eeprom_remove(struct i2c_client *client)
+{
+	struct eeprom_data *eeprom = i2c_get_clientdata(client);
+
+	i2c_slave_unregister(client);
+	sysfs_remove_bin_file(&client->dev.kobj, &eeprom->bin);
+
+	return 0;
+}
+
+static const struct i2c_device_id i2c_slave_eeprom_id[] = {
+	{ "slave-24c02", I2C_SLAVE_DEVICE_MAGIC(2048 / 8,  0) },
+	{ "slave-24c02ro", I2C_SLAVE_DEVICE_MAGIC(2048 / 8,  I2C_SLAVE_FLAG_RO) },
+	{ "slave-24c32", I2C_SLAVE_DEVICE_MAGIC(32768 / 8, I2C_SLAVE_FLAG_ADDR16) },
+	{ "slave-24c32ro", I2C_SLAVE_DEVICE_MAGIC(32768 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) },
+	{ "slave-24c64", I2C_SLAVE_DEVICE_MAGIC(65536 / 8, I2C_SLAVE_FLAG_ADDR16) },
+	{ "slave-24c64ro", I2C_SLAVE_DEVICE_MAGIC(65536 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) },
+	{ "slave-24c512", I2C_SLAVE_DEVICE_MAGIC(524288 / 8, I2C_SLAVE_FLAG_ADDR16) },
+	{ "slave-24c512ro", I2C_SLAVE_DEVICE_MAGIC(524288 / 8, I2C_SLAVE_FLAG_ADDR16 | I2C_SLAVE_FLAG_RO) },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, i2c_slave_eeprom_id);
+
+static struct i2c_driver i2c_slave_eeprom_driver = {
+	.driver = {
+		.name = "i2c-slave-eeprom",
+	},
+	.probe = i2c_slave_eeprom_probe,
+	.remove = i2c_slave_eeprom_remove,
+	.id_table = i2c_slave_eeprom_id,
+};
+module_i2c_driver(i2c_slave_eeprom_driver);
+
+MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
+MODULE_DESCRIPTION("I2C slave mode EEPROM simulator");
+MODULE_LICENSE("GPL v2");