serial: 8250_exar: Replace custom EEPROM code with eeprom_93cx6

From: Parker Newman <[email protected]>

This series of patches replaces the custom 93cx6 EEPROM read functions in the 8250_exar driver with the eeprom_93cx6 driver. This removes duplicate code and improves code readability.

In order to use the eeprom_93cx6 driver a quirk needed to be added to add an extra clock cycle before reading from the EEPROM. This is similar to the quirk in the eeprom_93xx46 driver.

More details in associated patch and mailing list discussion with Andy Shevchenko about these changes:

Changes in v2:
- Dropped patch 3 "misc: eeprom: eeprom_93cx6: Replace printk(KERN_ERR...) with pr_err()".
- Moved Kconfig change into main patch.
- Moved quirk define into struct eeprom_93cx6.
- Moved quirk check function into eeprom_93cx6.h.
- Refactored cti_read_osc_freq() based on feedback.
- Minor commit message formatting fixes.

Changes in v3:
- Rebased to v6.12-rc1.
- Minor commit message rewording.
- Replace CTI_EE_MASK_OSC_FREQ_UPPER/LOWER with a single define in patch 4.
- Add patch 5 from Andy Shevchenko: "serial: 8250_exar: Group CTI EEPROM offsets by device".

Changes in v4:
- Remove trailing newline in patch 1.
- Move CTI_EE_MASK_OSC_FREQ change from patch 4 to patch 3.

Andy Shevchenko (1):
serial: 8250_exar: Group CTI EEPROM offsets by device

Parker Newman (4):
misc: eeprom: eeprom_93cx6: Add quirk for extra read clock cycle
misc: eeprom: eeprom_93cx6: Switch to BIT() macro
serial: 8250_exar: Replace custom EEPROM read with eeprom_93cx6
serial: 8250_exar: Remove old exar_ee_read() and other unneeded code

 drivers/misc/eeprom/eeprom_93cx6.c  |  15 +++-
 drivers/tty/serial/8250/8250_exar.c | 130 ++++++++--------------------
 drivers/tty/serial/8250/Kconfig     |   1 +
 include/linux/eeprom_93cx6.h        |  11 +++
 4 files changed, 62 insertions(+), 95 deletions(-)

base-commit: 9852d85ec9d492ebef56dc5f229416c925758edc --
2.46.0