On 09/22/2015 01:36 AM, Arnd Bergmann wrote:
On Saturday 19 September 2015 01:36:43 Constantine Shulyupin wrote:I am designing DT support for a hwmon chip. It has some sensors, each of them can be: - "disabled" - "thermal diode" - "thermistor" - "voltage" Four possible options for DT properties format. Option 1: Separated property for each sensor. Example nct7802 node: nct7802 { compatible = "nuvoton,nct7802"; reg = <0x2a>; nuvoton,sensor1-type = "thermistor"; nuvoton,sensor2-type = "disabled"; nuvoton,sensor3-type = "voltage"; }; Option 2: Array of strings for all sensors. nct7802 { compatible = "nuvoton,nct7802"; reg = <0x2a>; nuvoton,sensors-types = "thermistor", "disabled", "voltage"; }; Option 3: Sets of 4 cells. Borrowed from marvell,reg-init and broadcom,c45-reg-init. The first cell is the page address, the second a register address within the page, the third cell contains a mask to be ANDed with the existing register value, and the fourth cell is ORed with the result to yield the new register value. If the third cell has a value of zero, no read of the existing value is performed. Example nct7802 node: nct7802 { compatible = "nuvoton,nct7802"; reg = <0x2a>; nct7802,reg-init = <0 0x21 0 0x01 > // START = 1 <0 0x22 0x03 0x02>; // RTD1_MD = 2 };I would strongly prefer Option 1 or 2 over option 3. Between 1 and 2, I'd probably go for 1. Another option might be to have a subnode per sensor: nct7802@2a { compatible = "nuvoton,nct7802"; reg = <0x2a>; #address-cells=<1>; #size-cells=<0>; sensor@1 { compatible = "nuvoton,nct7802-thermistor"; further-properties; }; sensor@3 { compatible = "nuvoton,nct7802-voltage"; for-example-range-mv = <0 5000>; }; };
I personally would prefer this approach. It would also make it easier to add more properties. Wonder what is more appropriate, though - a compatible property or something like the following ? sensor-type = "xxx"; I don't have a preference, just asking. Also, would the index be derived from "@1", or should there be a reg property ?
In either case, I'd say that disabled sensors should not need to be listed.
Agreed. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
