dts/bindings/clocks: stm32: 'clock-names' optional for source clock setting

Since implementation of clock source selection in consumer device drivers
could be achieved without usage of a clock-names property and no
example of usage is provided up to now, remove this property from existing
examples.
Additionally, make it clear in stm32 clock control binding that it is
driver's responsibility to correctly access clock source information
and use it as required.

Signed-off-by: Erwan Gouriou <[email protected]>

Author: erwango

dts/bindings/clock/st,stm32-rcc.yaml

@@ -37,6 +37,20 @@ description: |
   the bus controlling the peripheral and the second index specifies the bit used to
   control the peripheral clock in that bus register.
 
+  Specifying an alternate clock source:
+
+  Specifying an alternate source clock could be done by adding a clock specifier to the
+  clock property:
+  ... {
+           ...
+           clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00000020>,
+                        <&rcc STM32_SRC_HSI I2C1_SEL(2)>;
+           ...
+  }
+  In this example I2C1 device is assigned HSI as clock source.
+  It is device driver's responsibility to querry and use clock source information in
+  accordance with clock_control API specifications.
+
 compatible: "st,stm32-rcc"
 
 include: [clock-controller.yaml, base.yaml]

tests/drivers/clock_control/stm32_clock_configuration/stm32h7_devices/boards/spi1_per_ck_d1ppre_1.overlay

@@ -23,6 +23,5 @@
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>,
 		 <&rcc STM32_SRC_CKPER SPI123_SEL(4)>;
-	clock-names = "reg", "kernel";
 	status = "okay";
 };

tests/drivers/clock_control/stm32_clock_configuration/stm32h7_devices/boards/spi1_per_ck_hsi.overlay

@@ -23,6 +23,5 @@
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>,
 		 <&rcc STM32_SRC_CKPER SPI123_SEL(4)>;
-	clock-names = "reg", "kernel";
 	status = "okay";
 };

tests/drivers/clock_control/stm32_clock_configuration/stm32h7_devices/boards/spi1_pll3p_1_d1ppre_4.overlay

@@ -26,6 +26,5 @@
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>,
 		 <&rcc STM32_SRC_PLL3_P SPI123_SEL(2)>;
-	clock-names = "reg", "kernel";
 	status = "okay";
 };

tests/drivers/clock_control/stm32_clock_configuration/stm32h7_devices/boards/spi1_pllq_1_d1ppre_1.overlay

@@ -23,6 +23,5 @@
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>,
 		 <&rcc STM32_SRC_PLL1_Q SPI123_SEL(0)>;
-	clock-names = "reg", "kernel";
 	status = "okay";
 };

tests/drivers/clock_control/stm32_clock_configuration/stm32h7_devices/boards/spi1_pllq_2_d1ppre_4.overlay

@@ -28,6 +28,5 @@
 &spi1 {
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>;
-	clock-names = "reg";
 	status = "okay";
 };

tests/drivers/spi/spi_loopback/boards/nucleo_h723zg.overlay

@@ -15,5 +15,4 @@
 	/delete-property/ clocks;
 	clocks = <&rcc STM32_CLOCK_BUS_APB2 0x00001000>,
 		 <&rcc STM32_SRC_PLL1_Q SPI123_SEL(0)>;
-	clock-names = "reg", "kernel";
 };