From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Date: Thu, 8 Jun 2023 06:18:10 -0700 Subject: [v6 2/4] dt-bindings: hwmon: Add ASPEED TACH Control documentation In-Reply-To: References: <20230608021839.12769-1-billy_tsai@aspeedtech.com> <20230608021839.12769-3-billy_tsai@aspeedtech.com> Message-ID: List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On 6/7/23 23:21, Billy Tsai wrote: > ??????? > The code says: > > ??????? > In Aspeed AST2600 SoC features 16 TACH controllers, with each > > ??????? > controller capable of supporting up to 1 input. > > ??????? > which is a bit different. I guess there are no examples anymore, > > ??????? > but I'd really like to see how this looks like in the devicetree file, > > ??????? > and how the driver is supposed to distinguish/select the 16 inputs. > > Hi Roeck, > > The node in the devicetree file will looks like following: > > tach0: tach0 at 1e610008 { > > ??????? compatible = "aspeed,ast2600-tach"; > > ??????? reg = <0x1e610008 0x8>; > > ??????? #address-cells = <1>; > > ??????? #size-cells = <0>; > > ??????? pinctrl-names = "default"; > > ??????? pinctrl-0 = <&pinctrl_tach0_default>; > > ??????? clocks = <&syscon ASPEED_CLK_AHB>; > > ??????? resets = <&syscon ASPEED_RESET_PWM>; > > ??????? status = "disabled"; > > }; > Neither reg nor pinctrl is mentioned in the bindings. Maybe that is not needed nowadays, but I find it confusing. Either case, it is highly unusual that there would be 16 instances of this device instead of one. Why is this done ? It doesn't really make sense to me. Guenter