On Wed, 02 Dec 2020, Lee Jones wrote:

On Sun, 22 Nov 2020, Jonathan Neuschäfer wrote:

quoted

The Netronix embedded controller is a microcontroller found in some
e-book readers designed by the original design manufacturer Netronix,
Inc. It contains RTC, battery monitoring, system power management, and
PWM functionality.

This driver implements register access and version detection.

Third-party hardware documentation is available at:

  https://github.com/neuschaefer/linux/wiki/Netronix-MSP430-embedded-controller

The EC supports interrupts, but the driver doesn't make use of them so
far.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---

v4:
- include asm/unaligned.h after linux/*
- Use put_unaligned_be16 instead of open-coded big-endian packing
- Clarify that 0x90=0xff00 causes an error in downstream kernel too
- Add commas after non-sentinel positions
- ntxec.h: declare structs device and regmap
- Replace WARN_ON usage and add comments to explain errors
- Replace dev_alert with dev_warn when the result isn't handled
- Change subdevice registration error message to dev_err
- Declare ntxec_reg8 as returning __be16
- Restructure version detection code
- Spell out ODM

v3:
- https://lore.kernel.org/lkml/20200924192455.2484005-4-j.neuschaefer@gmx.net/ (local)
- Add (EC) to CONFIG_MFD_NTXEC prompt
- Relicense as GPLv2 or later
- Add email address to copyright line
- remove empty lines in ntxec_poweroff and ntxec_restart functions
- Split long lines
- Remove 'Install ... handler' comments
- Make naming of struct i2c_client parameter consistent
- Remove struct ntxec_info
- Rework 'depends on' lines in Kconfig, hard-depend on I2C, select REGMAP_I2C and
  MFD_CORE
- Register subdevices via mfd_cells
- Move 8-bit register conversion to ntxec.h

v2:
- https://lore.kernel.org/lkml/20200905133230.1014581-4-j.neuschaefer@gmx.net/ (local)
- Add a description of the device to the patch text
- Unify spelling as 'Netronix embedded controller'.
  'Netronix' is the proper name of the manufacturer, but 'embedded controller'
  is just a label that I have assigned to the device.
- Switch to regmap, avoid regmap use in poweroff and reboot handlers.
  Inspired by cf84dc0bb40f4 ("mfd: rn5t618: Make restart handler atomic safe")
- Use a list of known-working firmware versions instead of checking for a
  known-incompatible version
- Prefix registers with NTXEC_REG_
- Define register values as constants
- Various style cleanups as suggested by Lee Jones
- Don't align = signs in struct initializers [Uwe Kleine-König]
- Don't use dev_dbg for an error message
- Explain sleep in poweroff handler
- Remove (struct ntxec).client
- Switch to .probe_new in i2c driver
- Add .remove callback
- Make CONFIG_MFD_NTXEC a tristate option
---
 drivers/mfd/Kconfig       |  11 ++
 drivers/mfd/Makefile      |   1 +
 drivers/mfd/ntxec.c       | 216 ++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/ntxec.h |  34 ++++++
 4 files changed, 262 insertions(+)
 create mode 100644 drivers/mfd/ntxec.c
 create mode 100644 include/linux/mfd/ntxec.h

[...]

quoted

+	/* Bail out if we encounter an unknown firmware version */
+	switch (version) {
+	case 0xd726: /* found in Kobo Aura */

No magic numbers.

Please submit a subsequent patch to define this.

quoted

+		break;
+	default:
+		dev_err(ec->dev,
+			"Netronix embedded controller version %04x is not supported.\n",
+			version);
+		return -ENODEV;
+	}

Applied, thanks.

Sorry, that should have been:

For my own reference (apply this as-is to your sign-off block):

  Acked-for-MFD-by: Lee Jones [off-list ref]

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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