Commit 82d51481 authored by Björn Ardö's avatar Björn Ardö Committed by Wolfram Sang
Browse files

i2c-eeprom_slave: Add support for more eeprom models 



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

Signed-off-by: default avatarBjörn Ardö <bjorn.ardo@axis.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 0a321b97

drivers/i2c/i2c-slave-eeprom.c

+25 −11
Original line number Diff line number Diff line
@@ -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);