Am 25.01.2018 um 17:07 schrieb Bartosz Golaszewski:
> 2018-01-25 14:40 GMT+01:00 Johannes Poehlmann <johannes.poehlmann@xxxxxxxxxxx>:
>> Hi Bartosz,
>>
>> The patch was build against recent linus master
>> commit 5b7d27967dabfb17c21b0d98b29153b9e3ee71e5
>> Merge: f165495 624ca9c
>> Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> Date: Wed Jan 24 17:24:30 2018 -0800
>>
>> checkpatch.pl run to 0 Errors
>> tested on powerpc 32bit
>>
>> Any recommendations/comments ?
>>
>>
>> -------------------------------------------------------------------
>>
>> Signed-off-by: Johannes Poehlmann <johannes.poehlmann@xxxxxxxxxxx>
>>
>> needed with some eeprom chips
>> modelled after at25
>> ---
>> .../devicetree/bindings/eeprom/eeprom.txt | 3 +++
>> drivers/misc/eeprom/at24.c | 24 ++++++++++++++++++++--
>> 2 files changed, 25 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/eeprom/eeprom.txt b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> index 27f2bc1..8f3293c 100644
>> --- a/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> +++ b/Documentation/devicetree/bindings/eeprom/eeprom.txt
>> @@ -38,10 +38,13 @@ Optional properties:
>>
>> - size: total eeprom size in bytes
>>
>> + - address-width : number of address bits (8 or 16)
>> +
>> Example:
>>
>> eeprom@52 {
>> compatible = "atmel,24c32";
>> reg = <0x52>;
>> pagesize = <32>;
>> + address-width = <16>;
>> };
>> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
>> index 4d63ac8..2a6d476 100644
>> --- a/drivers/misc/eeprom/at24.c
>> +++ b/drivers/misc/eeprom/at24.c
>> @@ -651,11 +651,27 @@ static int at24_write(void *priv, unsigned int off, void *val, size_t count)
>> return 0;
>> }
>>
>> -static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>> +static int at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>> {
>> int err;
>> u32 val;
>>
>> + if (device_property_read_u32(dev, "address-width", &val) == 0) {
>> + switch (val) {
>> + case 8:
>> + chip->flags &= ~AT24_FLAG_ADDR16;
>> + break;
>> + case 16:
>> + chip->flags |= AT24_FLAG_ADDR16;
>> + break;
>> + default:
>> + dev_err(dev,
>> + "Error: bad \"address-width\" property: %u\n",
>> + val);
>> + return -ENODEV;
>> + }
>> + }
>> +
>> if (device_property_present(dev, "read-only"))
>> chip->flags |= AT24_FLAG_READONLY;
>>
>> @@ -674,6 +690,7 @@ static void at24_get_pdata(struct device *dev, struct at24_platform_data *chip)
>> */
>> chip->page_size = 1;
>> }
>> + return 0;
>> }
>>
>> static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>> @@ -716,7 +733,10 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id)
>> magic >>= AT24_SIZE_BYTELEN;
>> chip.flags = magic & AT24_BITMASK(AT24_SIZE_FLAGS);
>>
>> - at24_get_pdata(&client->dev, &chip);
>> + err = at24_get_pdata(&client->dev, &chip);
>> + if (err)
>> + return err;
>> +
>>
>> chip.setup = NULL;
>> chip.context = NULL;
>> --
>> 2.1.4
>>
>
> What EEPROM model do you need that for? Is it not covered by all the
> standard types we already support in the driver?
>
> Thanks,
> Bartosz
>
Hi Bartosz,
I need this for a M24M01-D* eeprom.
(http://www.st.com/content/ccc/resource/technical/document/datasheet/group0/cb/91/ba/7d/0b/c1/4d/f6/CD00147128/files/CD00147128.pdf/jcr:content/translations/en.CD00147128.pdf)
It is 1 Mbit sized and has 2 byte addresses.
Under another I2C address it offers a additional write lockable page
of 256 Byte, but with _2 byte addresses_. I could not correctly read
this "second eeprom" with one of the standard eeprom at24* models.
With the patch and using a device tree entry of
compatible = "at,24c02";
address-width = <16>;
reg = <0x5C>;
pagesize = <256>;
gave me a 256 Byte "eeprom" file in sysfs with no errors.
Regards
Johannes
