2018-01-26 11:13 GMT+01:00 Johannes Pöhlmann <johannes.poehlmann@xxxxxxxxxxx>:
> 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
This model is compatible with at24cm01. We don't support it yet, but
instead of a new DT property, just add a new supported model with
compatible = 'atmel,at24cm01' and AT24_FLAG_ADDR16 to the driver code.
Thanks,
Bartosz
