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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
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parentInitial commit. (diff)
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Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+STMicroelectronics STM32 Reset and Clock Controller
+===================================================
+
+The RCC IP is both a reset and a clock controller.
+
+Please refer to clock-bindings.txt for common clock controller binding usage.
+Please also refer to reset.txt for common reset controller binding usage.
+
+Required properties:
+- compatible: Should be:
+ "st,stm32f42xx-rcc"
+ "st,stm32f469-rcc"
+ "st,stm32f746-rcc"
+ "st,stm32f769-rcc"
+
+- reg: should be register base and length as documented in the
+ datasheet
+- #reset-cells: 1, see below
+- #clock-cells: 2, device nodes should specify the clock in their "clocks"
+ property, containing a phandle to the clock device node, an index selecting
+ between gated clocks and other clocks and an index specifying the clock to
+ use.
+- clocks: External oscillator clock phandle
+ - high speed external clock signal (HSE)
+ - external I2S clock (I2S_CKIN)
+
+Example:
+
+ rcc: rcc@40023800 {
+ #reset-cells = <1>;
+ #clock-cells = <2>
+ compatible = "st,stm32f42xx-rcc", "st,stm32-rcc";
+ reg = <0x40023800 0x400>;
+ clocks = <&clk_hse>, <&clk_i2s_ckin>;
+ };
+
+Specifying gated clocks
+=======================
+
+The primary index must be set to 0.
+
+The secondary index is the bit number within the RCC register bank, starting
+from the first RCC clock enable register (RCC_AHB1ENR, address offset 0x30).
+
+It is calculated as: index = register_offset / 4 * 32 + bit_offset.
+Where bit_offset is the bit offset within the register (LSB is 0, MSB is 31).
+
+To simplify the usage and to share bit definition with the reset and clock
+drivers of the RCC IP, macros are available to generate the index in
+human-readble format.
+
+For STM32F4 series, the macro are available here:
+ - include/dt-bindings/mfd/stm32f4-rcc.h
+
+Example:
+
+ /* Gated clock, AHB1 bit 0 (GPIOA) */
+ ... {
+ clocks = <&rcc 0 STM32F4_AHB1_CLOCK(GPIOA)>
+ };
+
+ /* Gated clock, AHB2 bit 4 (CRYP) */
+ ... {
+ clocks = <&rcc 0 STM32F4_AHB2_CLOCK(CRYP)>
+ };
+
+Specifying other clocks
+=======================
+
+The primary index must be set to 1.
+
+The secondary index is bound with the following magic numbers:
+
+ 0 SYSTICK
+ 1 FCLK
+ 2 CLK_LSI (low-power clock source)
+ 3 CLK_LSE (generated from a 32.768 kHz low-speed external
+ crystal or ceramic resonator)
+ 4 CLK_HSE_RTC (HSE division factor for RTC clock)
+ 5 CLK_RTC (real-time clock)
+ 6 PLL_VCO_I2S (vco frequency of I2S pll)
+ 7 PLL_VCO_SAI (vco frequency of SAI pll)
+ 8 CLK_LCD (LCD-TFT)
+ 9 CLK_I2S (I2S clocks)
+ 10 CLK_SAI1 (audio clocks)
+ 11 CLK_SAI2
+ 12 CLK_I2SQ_PDIV (post divisor of pll i2s q divisor)
+ 13 CLK_SAIQ_PDIV (post divisor of pll sai q divisor)
+
+ 14 CLK_HSI (Internal ocscillator clock)
+ 15 CLK_SYSCLK (System Clock)
+ 16 CLK_HDMI_CEC (HDMI-CEC clock)
+ 17 CLK_SPDIF (SPDIF-Rx clock)
+ 18 CLK_USART1 (U(s)arts clocks)
+ 19 CLK_USART2
+ 20 CLK_USART3
+ 21 CLK_UART4
+ 22 CLK_UART5
+ 23 CLK_USART6
+ 24 CLK_UART7
+ 25 CLK_UART8
+ 26 CLK_I2C1 (I2S clocks)
+ 27 CLK_I2C2
+ 28 CLK_I2C3
+ 29 CLK_I2C4
+ 30 CLK_LPTIMER (LPTimer1 clock)
+ 31 CLK_PLL_SRC
+ 32 CLK_DFSDM1
+ 33 CLK_ADFSDM1
+ 34 CLK_F769_DSI
+)
+
+Example:
+
+ /* Misc clock, FCLK */
+ ... {
+ clocks = <&rcc 1 STM32F4_APB1_CLOCK(TIM2)>
+ };
+
+
+Specifying softreset control of devices
+=======================================
+
+Device nodes should specify the reset channel required in their "resets"
+property, containing a phandle to the reset device node and an index specifying
+which channel to use.
+The index is the bit number within the RCC registers bank, starting from RCC
+base address.
+It is calculated as: index = register_offset / 4 * 32 + bit_offset.
+Where bit_offset is the bit offset within the register.
+For example, for CRC reset:
+ crc = AHB1RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x10 / 4 * 32 + 12 = 140
+
+example:
+
+ timer2 {
+ resets = <&rcc STM32F4_APB1_RESET(TIM2)>;
+ };