ping
--
Christian Gmeiner, MSc
2012/12/19 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 2baeec5..723b411 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 {
> @@ -484,6 +494,7 @@ 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;
> @@ -547,6 +558,18 @@ 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
> @@ -562,6 +585,7 @@ 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;
>
> @@ -579,8 +603,7 @@ 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;
>
> --
> 1.7.12.2.421.g261b511
>
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