linux-toradex.git/drivers/misc/eeprom/Kconfig, branch master

eeprom: add driver for ST M24LR series RFID/NFC EEPROM chips

2025-08-19T10:51:22+00:00

adds support for STMicroelectronics M24LRxx devices, which expose
two separate I2C addresses: one for system control and one for EEPROM
access. The driver implements both a sysfs-based interface for control
registers (e.g. UID, password authentication) and an nvmem provider
for EEPROM access.

Signed-off-by: Abd-Alrhman Masalkhi 
Link: https://lore.kernel.org/r/20250717063934.5083-3-abd.masalkhi@gmail.com
Signed-off-by: Greg Kroah-Hartman

eeprom: at25: convert to spi-mem API

2025-07-16T12:24:52+00:00

Replace the RAW SPI accesses with spi-mem API. The latter will fall back to
RAW SPI accesses if spi-mem callbacks are not implemented by a controller
driver.

Notable advantages:
- read function now allocates a bounce buffer for SPI DMA compatibility,
  similar to write function;
- the driver can now be used in conjunction with SPI controller drivers
  providing spi-mem API only, e.g. spi-nxp-fspi.
- during the initial probe the driver polls busy/ready status bit for 25ms
  instead of giving up instantly and hoping that the FW didn't write the
  EEPROM

Notes:
- mutex_lock() has been dropped from fm25_aux_read() because the latter is
  only being called in probe phase and therefore cannot race with
  at25_ee_read() or at25_ee_write()

Quick 4KB block size test with CY15B102Q 256KB F-RAM over spi_omap2_mcspi
driver (no spi-mem ops provided, fallback to raw SPI inside spi-mem):

OP	| throughput, KB/s	| change
--------+-----------------------+-------
write	| 1717.847 -> 1656.684	| -3.6%
read	| 1115.868 -> 1059.367	| -5.1%

The lower throughtput probably comes from the 3 messages per SPI transfer
inside spi-mem instead of hand-crafted 2 messages per transfer in the
former at25 code. However, if the raw SPI access is not preserved, then
the driver doesn't grow from the lines-of-code perspective and subjectively
could be considered even a bit simpler.

Higher performance impact on the read operation could be explained by the
newly introduced bounce buffer in read operation. I didn't find any
explanation or guarantee, why would a bounce buffer be not needed on the
read side, so I assume it's a pure luck that nobody read EEPROM into
some variable on stack on an architecture where kernel stack would be
not DMA-able.

Cc: Michael Walle 
Cc: Hui Wang 
Link: https://lore.kernel.org/all/28ab8b72afee1af59b628f7389f0d7f5@kernel.org/
Signed-off-by: Alexander Sverdlin 
Link: https://lore.kernel.org/r/20250702222823.864803-1-alexander.sverdlin@siemens.com
Signed-off-by: Greg Kroah-Hartman

eeprom: Fix the cacography in Kconfig

2024-11-05T04:33:47+00:00

The word 'swtich' is wrong, so fix it.

Signed-off-by: Luo Yifan 
Link: https://lore.kernel.org/r/20241022062534.122428-1-luoyifan@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman

eeprom: ee1004: Add nvmem support

2024-07-04T10:02:56+00:00

Currently the driver does not register a nvmem provider, which means
that userspace programs cannot access the ee1004 EEPROM through the
standard nvmem sysfs API.
Fix this by replacing the custom sysfs attribute with a standard nvmem
interface, which also takes care of backwards compatibility.

Tested on a Dell Inspiron 3505.

Signed-off-by: Armin Wolf 
Link: https://lore.kernel.org/r/20240625063459.429953-2-W_Armin@gmx.de
Signed-off-by: Greg Kroah-Hartman

eeprom: Remove deprecated legacy eeprom driver

2023-10-05T09:09:40+00:00

Driver was marked deprecated 4 years ago, so it's time to remove it.
This driver is the only i2c client driver using class I2C_CLASS_SPD.
Apparently, as a follow-up step, we can remove I2C_CLASS_SPD
altogether.

Signed-off-by: Heiner Kallweit 
Reviewed-by: Jean Delvare 
Link: https://lore.kernel.org/r/18241458-52db-4537-bead-d570801253c3@gmail.com
Signed-off-by: Greg Kroah-Hartman

eeprom: at24: also select REGMAP

2023-06-08T07:58:57+00:00

Selecting only REGMAP_I2C can leave REGMAP unset, causing build errors,
so also select REGMAP to prevent the build errors.

../drivers/misc/eeprom/at24.c:540:42: warning: 'struct regmap_config' declared inside parameter list will not be visible outside of this definition or declaration
  540 |                                   struct regmap_config *regmap_config)
../drivers/misc/eeprom/at24.c: In function 'at24_make_dummy_client':
../drivers/misc/eeprom/at24.c:552:18: error: implicit declaration of function 'devm_regmap_init_i2c' [-Werror=implicit-function-declaration]
  552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
../drivers/misc/eeprom/at24.c:552:16: warning: assignment to 'struct regmap *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
  552 |         regmap = devm_regmap_init_i2c(dummy_client, regmap_config);
../drivers/misc/eeprom/at24.c: In function 'at24_probe':
../drivers/misc/eeprom/at24.c:586:16: error: variable 'regmap_config' has initializer but incomplete type
  586 |         struct regmap_config regmap_config = { };
../drivers/misc/eeprom/at24.c:586:30: error: storage size of 'regmap_config' isn't known
  586 |         struct regmap_config regmap_config = { };
../drivers/misc/eeprom/at24.c:586:30: warning: unused variable 'regmap_config' [-Wunused-variable]

Fixes: 5c015258478e ("eeprom: at24: add basic regmap_i2c support")
Signed-off-by: Randy Dunlap 
Signed-off-by: Bartosz Golaszewski

nvmem: prepare basics for FRAM support

2021-06-11T10:23:10+00:00

Added enum and string for FRAM (ferroelectric RAM) to expose it as file
named "fram".
Added documentation of sysfs file.

Signed-off-by: Jiri Prchal 
Link: https://lore.kernel.org/r/20210611094601.95131-2-jiri.prchal@aksignal.cz
Signed-off-by: Greg Kroah-Hartman

eeprom: Deprecate the legacy eeprom driver

2019-09-04T07:57:35+00:00

Time has come to get rid of the old eeprom driver. The at24 driver
should be used instead. So mark the eeprom driver as deprecated and
give users some time to migrate. Then we can remove the legacy
eeprom driver completely.

Signed-off-by: Jean Delvare 
Cc: Arnd Bergmann 
Link: https://lore.kernel.org/r/20190902104838.058725c2@endymion
Signed-off-by: Greg Kroah-Hartman

eeprom: make older eeprom drivers select NVMEM_SYSFS

2019-07-25T12:39:51+00:00

misc/eeprom/{at24,at25,eeprom_93xx46} drivers all register their
corresponding devices in the nvmem framework in compat mode which requires
nvmem sysfs interface to be present. The latter, however, has been split
out from nvmem under a separate Kconfig in commit ae0c2d725512 ("nvmem:
core: add NVMEM_SYSFS Kconfig"). As a result, probing certain I2C-attached
EEPROMs now fails with

  at24: probe of 0-0050 failed with error -38

because of a stub implementation of nvmem_sysfs_setup_compat()
in drivers/nvmem/nvmem.h. Update the nvmem dependency for these drivers
so they could load again:

  at24 0-0050: 32768 byte 24c256 EEPROM, writable, 64 bytes/write

Cc: Adrian Bunk 
Cc: Bartosz Golaszewski 
Cc: Srinivas Kandagatla 
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Arseny Solokha 
Link: https://lore.kernel.org/r/20190716111236.27803-1-asolokha@kb.kras.ru
Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman