From: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
To: krzk@kernel.org
Cc: abd.masalkhi@gmail.com, arnd@arndb.de, conor+dt@kernel.org,
devicetree@vger.kernel.org, gregkh@linuxfoundation.org,
krzk+dt@kernel.org, linux-kernel@vger.kernel.org,
robh@kernel.org
Subject: Re: [PATCH v2 1/3] dt-bindings: Add Device Tree binding for ST M24LR control interface
Date: Mon, 2 Jun 2025 17:23:27 +0000 [thread overview]
Message-ID: <20250602172327.2029611-1-abd.masalkhi@gmail.com> (raw)
In-Reply-To: <3c49628c-00b0-488d-a660-4b904febca1e@kernel.org>
Hi Krzysztof,
Thank you again for yourfeedback, it's been very helpful in
understanding how best to write the binding file represent
this device.
>> A Brief Overview of the Device:
>>
>> The M24LR series is a dual-interface EEPROM with both I2C and ISO/IEC 15693
>> RF support. While it is technically an EEPROM, it also exposes a control
>> interface over I2C via a second address, which is used to manage features
>> such as password protection, energy harvesting configuration, and UID access.
>> This secondary interface is not memory-mapped like traditional EEPROMs, which
>> is why I initially considered separating the control aspect in the software.
>>
>> How to Access the EEPROM and the System Parameter Sector?
>>
>> According to the datasheet for the M24LR04E-R, the E2 bit must be set
>> appropriately in the I2C device select code to distinguish between EEPROM
>> access and control access.
>>
>> What is E2?
>> E2 is a bit in the I2C device select code. It determines which internal
>> function of the chip is being accessed.
>>
>> Device Select Code Format:
>> Bit: b7 b6 b5 b4 b3 b2 b1 b0
>> Value: 1 0 1 0 E2 1 1 R/W
>>
>> To access the EEPROM memory, E2 (b3) should be 0:
>>
>> Device Select Code Format:
>> Bit: b7 b6 b5 b4 b3 b2 b1 b0
>> Value: 1 0 1 0 0 1 1 R/W
>>
>> To access the system control interface, E2 (b3) should be 1:
>
> So these are just two different addresses. I already commented on this.
> This is not I2C mux but a device with two addresses.
I'd like to clarify one point before proceeding further, If I remove
the i2c-mux usage from the binding file, as your recommendation, does
this also imply that I should stop using the i2c-mux API in my driver
implementation itself? and treat this as a multi-function device, or
Is it acceptable to keep the current driver logic as-is, while limiting
the change to just fixing the binding and device tree representation?
and if only the binding file, should i represent it as the following:
eeprom-ctl@57 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "st,m24lr04e-r";
reg = <0x57>;
}
Best regards,
Abd-Alrhman Masalkhi
next prev parent reply other threads:[~2025-06-02 17:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-01 15:30 [PATCH v2 0/3] Add control driver for ST M24LR RFID/NFC EEPROM chips Abd-Alrhman Masalkhi
2025-06-01 15:30 ` [PATCH v2 1/3] dt-bindings: eeprom: Add ST M24LR control interface Abd-Alrhman Masalkhi
2025-06-01 15:42 ` Krzysztof Kozlowski
2025-06-02 3:48 ` [PATCH v2 1/3] dt-bindings: Add Device Tree binding for " Abd-Alrhman Masalkhi
2025-06-02 6:28 ` Krzysztof Kozlowski
2025-06-02 17:23 ` Abd-Alrhman Masalkhi [this message]
2025-06-02 18:11 ` Krzysztof Kozlowski
2025-06-02 17:47 ` Abd-Alrhman Masalkhi
2025-06-01 16:33 ` [PATCH v2 1/3] dt-bindings: eeprom: Add " Rob Herring (Arm)
2025-06-03 5:40 ` Abd-Alrhman Masalkhi
2025-06-03 6:56 ` Krzysztof Kozlowski
2025-06-01 15:30 ` [PATCH v2 2/3] misc: add sysfs control driver for ST M24LR series RFID/NFC chips Abd-Alrhman Masalkhi
2025-06-01 15:30 ` [PATCH v2 3/3] ABI: sysfs: document control attributes for ST M24LR Abd-Alrhman Masalkhi
2025-06-01 15:50 ` [PATCH v2 0/3] Add control driver for ST M24LR RFID/NFC EEPROM chips Greg KH
-- strict thread matches above, loose matches on Subject: below --
2025-05-31 13:37 [PATCH 1/3] dt-bindings: misc: Add binding for ST M24LR control interface Krzysztof Kozlowski
2025-06-01 7:31 ` [PATCH v2 1/3] dt-bindings: Add Device Tree " Abd-Alrhman Masalkhi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250602172327.2029611-1-abd.masalkhi@gmail.com \
--to=abd.masalkhi@gmail.com \
--cc=arnd@arndb.de \
--cc=conor+dt@kernel.org \
--cc=devicetree@vger.kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=krzk+dt@kernel.org \
--cc=krzk@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=robh@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®