linux-kernel - Re: [PATCH v6 5/5] hwmon: Add support for Amphenol ChipCap 2

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Date: Fri, 2 Feb 2024 10:57:26 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Javier Carrasco <javier.carrasco.cruz@...il.com>
Cc: Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jean Delvare <jdelvare@...e.com>, Jonathan Corbet <corbet@....net>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, Rob Herring <robh@...nel.org>,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-hwmon@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v6 5/5] hwmon: Add support for Amphenol ChipCap 2

On Tue, Jan 30, 2024 at 10:06:48PM +0100, Javier Carrasco wrote:
> The Amphenol ChipCap 2 is a capacitive polymer humidity and temperature
> sensor with an integrated EEPROM and minimum/maximum humidity alarms.
> 
> All device variants offer an I2C interface and depending on the part
> number, two different output modes:
> - CC2D: digital output
> - CC2A: analog (PDM) output
> 
> This driver adds support for the digital variant (CC2D part numbers),
> which includes the following part numbers:
> - non-sleep measurement mode (CC2D23, CC2D25, CC2D33, CC2D35)
> - sleep measurement mode (CC2D23S, CC2D25S, CC2D33S, CC2D35S)
> 
> The Chipcap 2 EEPROM can be accessed to configure a series of parameters
> like the minimum/maximum humidity alarm threshold and hysteresis. The
> EEPROM is only accessible in the command window after a power-on reset.
> The default window lasts 10 ms if no Start_CM command is sent. After the
> command window is finished (either after the mentioned timeout of after
> a Start_NOM command is sent), the device enters the normal operation
> mode and makes a first measurement automatically.
> 
> Unfortunately, the device does not provide any hardware or software
> reset and therefore the driver must trigger power cycles to enter the
> command mode. A dedicated, external regulator is required for that.
> 
> This driver keeps the device off until a measurement or access to the
> EEPROM is required, making use of the first automatic measurement to
> avoid different code paths for sleep and non-sleep devices.
> 
> The minimum and maximum humidity alarms are configured with two
> registers per alarm: one stores the alarm threshold and the other one
> keeps the value that turns off the alarm. The alarm signals are only
> updated when a measurement is carried out.
> 
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>

Applied.

Thanks,
Guenter