summaryrefslogtreecommitdiff
path: root/drivers/i2c/i2c-slave-eeprom.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/i2c-slave-eeprom.c')
-rw-r--r--drivers/i2c/i2c-slave-eeprom.c109
1 files changed, 79 insertions, 30 deletions
diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c
index b2039f94c9d8..6bc2ef650a74 100644
--- a/drivers/i2c/i2c-slave-eeprom.c
+++ b/drivers/i2c/i2c-slave-eeprom.c
@@ -1,19 +1,23 @@
+// 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
*
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the
- * Free Software Foundation; version 2 of the License.
- *
- * Because most IP blocks can only detect one I2C slave address anyhow, this
- * driver does not support simulating EEPROM types which take more than one
- * address. It is prepared to simulate bigger EEPROMs with an internal 16 bit
- * pointer, yet implementation is deferred until the need actually arises.
+ * 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>
@@ -24,12 +28,20 @@
struct eeprom_data {
struct bin_attribute bin;
- bool first_write;
spinlock_t buffer_lock;
- u8 buffer_idx;
+ 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)
{
@@ -37,23 +49,27 @@ static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
switch (event) {
case I2C_SLAVE_WRITE_RECEIVED:
- if (eeprom->first_write) {
- eeprom->buffer_idx = *val;
- eeprom->first_write = false;
+ 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 {
- spin_lock(&eeprom->buffer_lock);
- eeprom->buffer[eeprom->buffer_idx++] = *val;
- spin_unlock(&eeprom->buffer_lock);
+ 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 */
+ fallthrough;
case I2C_SLAVE_READ_REQUESTED:
spin_lock(&eeprom->buffer_lock);
- *val = eeprom->buffer[eeprom->buffer_idx];
+ *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
@@ -64,7 +80,7 @@ static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
case I2C_SLAVE_STOP:
case I2C_SLAVE_WRITE_REQUESTED:
- eeprom->first_write = true;
+ eeprom->idx_write_cnt = 0;
break;
default:
@@ -75,12 +91,12 @@ static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
}
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)
+ const struct bin_attribute *attr, char *buf, loff_t off, size_t count)
{
struct eeprom_data *eeprom;
unsigned long flags;
- eeprom = dev_get_drvdata(container_of(kobj, struct device, kobj));
+ eeprom = dev_get_drvdata(kobj_to_dev(kobj));
spin_lock_irqsave(&eeprom->buffer_lock, flags);
memcpy(buf, &eeprom->buffer[off], count);
@@ -90,12 +106,12 @@ static ssize_t i2c_slave_eeprom_bin_read(struct file *filp, struct kobject *kobj
}
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)
+ const struct bin_attribute *attr, char *buf, loff_t off, size_t count)
{
struct eeprom_data *eeprom;
unsigned long flags;
- eeprom = dev_get_drvdata(container_of(kobj, struct device, kobj));
+ eeprom = dev_get_drvdata(kobj_to_dev(kobj));
spin_lock_irqsave(&eeprom->buffer_lock, flags);
memcpy(&eeprom->buffer[off], buf, count);
@@ -104,20 +120,48 @@ static ssize_t i2c_slave_eeprom_bin_write(struct file *filp, struct kobject *kob
return count;
}
-static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_device_id *id)
+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 = i2c_client_get_device_id(client);
struct eeprom_data *eeprom;
int ret;
- unsigned size = id->driver_data;
+ 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->first_write = true;
+ 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;
@@ -138,18 +182,23 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
return 0;
};
-static int i2c_slave_eeprom_remove(struct i2c_client *client)
+static void 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", 2048 / 8 },
+ { "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);
generated by cgit (git 2.34.1) at 2025-12-25 03:20:14 +0000