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i2c-eeprom_slave: Add support for more eeprom models

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Add a 32 and a 64 kbit memory. These needs 16 bit address
so added support for that as well.

Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Björn Ardö 2019-09-04 11:29:53 +02:00 committed by Wolfram Sang
parent 0a321b9736
commit 82d5148154
1 changed files with 25 additions and 11 deletions
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36
drivers/i2c/i2c-slave-eeprom.c
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@ -11,6 +11,7 @@
* pointer, yet implementation is deferred until the need actually arises.
*/
#include <linux/bitfield.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
@ -21,12 +22,18 @@
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;
u8 buffer[];
};
#define I2C_SLAVE_BYTELEN GENMASK(15, 0)
#define I2C_SLAVE_FLAG_ADDR16 BIT(16)
#define I2C_SLAVE_DEVICE_MAGIC(_len, _flags) ((_flags) | (_len))
static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
enum i2c_slave_event event, u8 *val)
{
@ -34,12 +41,14 @@ 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;
eeprom->buffer[eeprom->buffer_idx++ & eeprom->address_mask] = *val;
spin_unlock(&eeprom->buffer_lock);
}
break;
@ -50,7 +59,7 @@ static int i2c_slave_eeprom_slave_cb(struct i2c_client *client,
/* 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
@ -61,7 +70,7 @@ 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:
@ -105,13 +114,16 @@ static int i2c_slave_eeprom_probe(struct i2c_client *client, const struct i2c_de
{
struct eeprom_data *eeprom;
int ret;
unsigned size = id->driver_data;
unsigned int size = FIELD_GET(I2C_SLAVE_BYTELEN, id->driver_data);
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->idx_write_cnt = 0;
eeprom->num_address_bytes = flag_addr16 ? 2 : 1;
eeprom->address_mask = size - 1;
spin_lock_init(&eeprom->buffer_lock);
i2c_set_clientdata(client, eeprom);
@ -146,7 +158,9 @@ static int i2c_slave_eeprom_remove(struct i2c_client *client)
}
static const struct i2c_device_id i2c_slave_eeprom_id[] = {
{ "slave-24c02", 2048 / 8 },
{ "slave-24c02", I2C_SLAVE_DEVICE_MAGIC(2048 / 8, 0) },
{ "slave-24c32", I2C_SLAVE_DEVICE_MAGIC(32768 / 8, I2C_SLAVE_FLAG_ADDR16) },
{ "slave-24c64", I2C_SLAVE_DEVICE_MAGIC(65536 / 8, I2C_SLAVE_FLAG_ADDR16) },
{ }
};
MODULE_DEVICE_TABLE(i2c, i2c_slave_eeprom_id);