ping -- Christian Gmeiner, MSc https://soundcloud.com/christian-gmeiner 2014-10-09 11:07 GMT+02:00 Christian Gmeiner <christian.gmeiner@xxxxxxxxx>: > I have a at24 EEPROM connected via i2c bus provided by ISCH i2c > bus driver. This bus driver does not support > I2C_FUNC_SMBUS_WRITE_I2C_BLOCK and so I was looking for a way > to be able to write the eeprom. This patch adds support for > I2C_SMBUS_BYTE_DATA writing via i2c_smbus_write_byte_data. > It is quite slow, but it works. > > Signed-off-by: Christian Gmeiner <christian.gmeiner@xxxxxxxxx> > --- > drivers/misc/eeprom/at24.c | 35 +++++++++++++++++++++++++++++------ > 1 file changed, 29 insertions(+), 6 deletions(-) > > diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c > index d87f77f..f51daac 100644 > --- a/drivers/misc/eeprom/at24.c > +++ b/drivers/misc/eeprom/at24.c > @@ -56,6 +56,7 @@ struct at24_data { > struct at24_platform_data chip; > struct memory_accessor macc; > int use_smbus; > + int use_smbuse_write; > > /* > * Lock protects against activities from other Linux tasks, > @@ -324,7 +325,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, > { > struct i2c_client *client; > struct i2c_msg msg; > - ssize_t status; > + ssize_t status = 0; > unsigned long timeout, write_time; > unsigned next_page; > > @@ -365,9 +366,18 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, > timeout = jiffies + msecs_to_jiffies(write_timeout); > do { > write_time = jiffies; > - if (at24->use_smbus) { > - status = i2c_smbus_write_i2c_block_data(client, > - offset, count, buf); > + if (at24->use_smbuse_write) { > + switch (at24->use_smbuse_write) { > + case I2C_SMBUS_I2C_BLOCK_DATA: > + status = i2c_smbus_write_i2c_block_data(client, > + offset, count, buf); > + break; > + case I2C_SMBUS_BYTE_DATA: > + status = i2c_smbus_write_byte_data(client, > + offset, buf[0]); > + break; > + } > + > if (status == 0) > status = count; > } else { > @@ -487,6 +497,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > struct at24_platform_data chip; > bool writable; > int use_smbus = 0; > + int use_smbus_write = 0; > struct at24_data *at24; > int err; > unsigned i, num_addresses; > @@ -546,6 +557,18 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > } > } > > + /* Use I2C operations unless we're stuck with SMBus extensions. */ > + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { > + if (i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) { > + use_smbus_write = I2C_SMBUS_I2C_BLOCK_DATA; > + } else if (i2c_check_functionality(client->adapter, > + I2C_FUNC_SMBUS_WRITE_BYTE_DATA)) { > + use_smbus_write = I2C_SMBUS_BYTE_DATA; > + chip.page_size = 1; > + } > + } > + > if (chip.flags & AT24_FLAG_TAKE8ADDR) > num_addresses = 8; > else > @@ -559,6 +582,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > > mutex_init(&at24->lock); > at24->use_smbus = use_smbus; > + at24->use_smbuse_write = use_smbus_write; > at24->chip = chip; > at24->num_addresses = num_addresses; > > @@ -576,8 +600,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) > > writable = !(chip.flags & AT24_FLAG_READONLY); > if (writable) { > - if (!use_smbus || i2c_check_functionality(client->adapter, > - I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)) { > + if (!use_smbus || use_smbus_write) { > > unsigned write_max = chip.page_size; > > -- > 1.9.3 > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
