diff options
Diffstat (limited to 'drivers/i2c/i2c-slave-eeprom.c')
| -rw-r--r-- | drivers/i2c/i2c-slave-eeprom.c | 54 |
1 files changed, 41 insertions, 13 deletions
diff --git a/drivers/i2c/i2c-slave-eeprom.c b/drivers/i2c/i2c-slave-eeprom.c index be65d3842878..db9763cb4dae 100644 --- a/drivers/i2c/i2c-slave-eeprom.c +++ b/drivers/i2c/i2c-slave-eeprom.c @@ -11,6 +11,13 @@ * pointer, yet implementation is deferred until the need actually arises. */ +/* + * 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/i2c.h> #include <linux/init.h> #include <linux/module.h> @@ -21,12 +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)) + static int i2c_slave_eeprom_slave_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) { @@ -34,13 +49,17 @@ 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; @@ -50,7 +69,7 @@ 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 +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: @@ -105,13 +124,17 @@ 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; + eeprom->read_only = FIELD_GET(I2C_SLAVE_FLAG_RO, id->driver_data); spin_lock_init(&eeprom->buffer_lock); i2c_set_clientdata(client, eeprom); @@ -146,7 +169,12 @@ 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-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) }, { } }; MODULE_DEVICE_TABLE(i2c, i2c_slave_eeprom_id); |