[PATCH v3 2/7] bindings: spi-samsung: document the clocks and the clock-name property
From: s.nawrocki@samsung.com (Sylwester Nawrocki)
Date: 2016-07-18 10:30:07
Also in:
linux-clk, linux-devicetree, linux-samsung-soc, linux-spi
On 07/16/2016 10:30 PM, Rob Herring wrote:
quoted
diff --git a/Documentation/devicetree/bindings/spi/spi-samsung.txtb/Documentation/devicetree/bindings/spi/spi-samsung.txtquoted
index 57d5539..f45c6eb 100644--- a/Documentation/devicetree/bindings/spi/spi-samsung.txt +++ b/Documentation/devicetree/bindings/spi/spi-samsung.txt@@ -24,6 +24,15 @@ Required SoC Specific Properties: - dma-names: Names for the dma channels. There must be at least one channel named "tx" for transmit and named "rx" for receive. +- clocks: specifies the clock IDs provided to the SPI controller; they are + required for interacting with the controller itself, for synchronizing the bus + and as I/O clock (the latter is required by exynos5433 and exynos7). + +- clock-names: string names of the clocks in the 'clocks' property; for all the + the devices the names must be "spi", "spi_busclkN" (where N is determined by + "samsung,spi-src-clk"), while Exynos5433 should specify a third clockThis sounds like you are describing the configuration of the clocks, not the connections. The binding here should list clocks for all possible vaules of N as those are all the input clocks to the block.quoted
quoted
+ "spi_ioclk" for the I/O clock.
I agree we should list all possible spi_busclkN, I must admit I might have introduced some confusion by suggesting wording for clock-names similar to the above while discussing those things internally. Afterwards I came to a similar conclusion all possible input clocks should be listed These will differ depending on the compatible. I checked in documentation of most of related SoCs and for "samsung,s3c6410-spi" or older compatibles possible N is 0..2 (PCLK, USBCLK, PLL clock), for "samsung,s5pv210-spi" and newer possible N is 0 (SCLK_SPI). It's important to have all the input clocks listed so we have a list of parent clocks to the SPI controller's internal clocks, should we ever decide to model them with the clk API. -- Thanks, Sylwester