| What: /sys/bus/i2c/devices/<busnum>-<primary-addr>/unlock |
| Date: 2025-07-04 |
| KernelVersion: 6.17 |
| Contact: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> |
| Description: |
| Write-only attribute used to present a password and unlock |
| access to protected areas of the M24LR chip, including |
| configuration registers such as the Sector Security Status |
| (SSS) bytes. A valid password must be written to enable write |
| access to these regions via the I2C interface. |
| |
| Format: |
| - Hexadecimal string representing a 32-bit (4-byte) password |
| - Accepts 1 to 8 hex digits (e.g., "c", "1F", "a1b2c3d4") |
| - No "0x" prefix, whitespace, or trailing newline |
| - Case-insensitive |
| |
| Behavior: |
| - If the password matches the internal stored value, |
| access to protected memory/configuration is granted |
| - If the password does not match the internally stored value, |
| it will fail silently |
| |
| What: /sys/bus/i2c/devices/<busnum>-<primary-addr>/new_pass |
| Date: 2025-07-04 |
| KernelVersion: 6.17 |
| Contact: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> |
| Description: |
| Write-only attribute used to update the password required to |
| unlock the M24LR chip. |
| |
| Format: |
| - Hexadecimal string representing a new 32-bit password |
| - Accepts 1 to 8 hex digits (e.g., "1A", "ffff", "c0ffee00") |
| - No "0x" prefix, whitespace, or trailing newline |
| - Case-insensitive |
| |
| Behavior: |
| - Overwrites the current password stored in the I2C password |
| register |
| - Requires the device to be unlocked before changing the |
| password |
| - If the device is locked, the write silently fails |
| |
| What: /sys/bus/i2c/devices/<busnum>-<primary-addr>/uid |
| Date: 2025-07-04 |
| KernelVersion: 6.17 |
| Contact: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> |
| Description: |
| Read-only attribute that exposes the 8-byte unique identifier |
| programmed into the M24LR chip at the factory. |
| |
| Format: |
| - Lowercase hexadecimal string representing a 64-bit value |
| - 1 to 16 hex digits (e.g., "e00204f12345678") |
| - No "0x" prefix |
| - Includes a trailing newline |
| |
| What: /sys/bus/i2c/devices/<busnum>-<primary-addr>/total_sectors |
| Date: 2025-07-04 |
| KernelVersion: 6.17 |
| Contact: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> |
| Description: |
| Read-only attribute that exposes the total number of EEPROM |
| sectors available in the M24LR chip. |
| |
| Format: |
| - 1 to 2 hex digits (e.g. "F") |
| - No "0x" prefix |
| - Includes a trailing newline |
| |
| Notes: |
| - Value is encoded by the chip and corresponds to the EEPROM |
| size (e.g., 3 = 4 kbit for M24LR04E-R) |
| |
| What: /sys/bus/i2c/devices/<busnum>-<primary-addr>/sss |
| Date: 2025-07-04 |
| KernelVersion: 6.17 |
| Contact: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> |
| Description: |
| Read/write binary attribute representing the Sector Security |
| Status (SSS) bytes for all EEPROM sectors in STMicroelectronics |
| M24LR chips. |
| |
| Each EEPROM sector has one SSS byte, which controls I2C and |
| RF access through protection bits and optional password |
| authentication. |
| |
| Format: |
| - The file contains one byte per EEPROM sector |
| - Byte at offset N corresponds to sector N |
| - Binary access only; use tools like dd, Python, or C that |
| support byte-level I/O and offset control. |
| |
| Notes: |
| - The number of valid bytes in this file is equal to the |
| value exposed by 'total_sectors' file |
| - Write access requires prior password authentication in |
| I2C mode |
| - Refer to the M24LR datasheet for full SSS bit layout |
