summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorGabriel Fernandez <gabriel.fernandez@st.com>2017-08-21 13:59:02 +0200
committerStephen Boyd <sboyd@codeaurora.org>2017-08-31 18:35:47 -0700
commit3e4d618b0722b64c551c3f2fc4c4f9cb3558ed93 (patch)
treef41a5b11fd021214e2f6d8186f54ddb74f5511ab /Documentation
parent0a9c869d5c568054a828a38357f30d77659e5b1e (diff)
downloadlinux-3e4d618b0722b64c551c3f2fc4c4f9cb3558ed93.tar.gz
linux-3e4d618b0722b64c551c3f2fc4c4f9cb3558ed93.tar.bz2
linux-3e4d618b0722b64c551c3f2fc4c4f9cb3558ed93.zip
clk: stm32h7: Add stm32h743 clock driver
This patch enables clocks for STM32H743 boards. Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com> for MFD changes: Acked-by: Lee Jones <lee.jones@linaro.org> for DT-Bindings Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt71
1 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
new file mode 100644
index 000000000000..a135504c7d57
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/st,stm32h7-rcc.txt
@@ -0,0 +1,71 @@
+STMicroelectronics STM32H7 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,stm32h743-rcc"
+
+- reg: should be register base and length as documented in the
+ datasheet
+
+- #reset-cells: 1, see below
+
+- #clock-cells : from common clock binding; shall be set to 1
+
+- clocks: External oscillator clock phandle
+ - high speed external clock signal (HSE)
+ - low speed external clock signal (LSE)
+ - external I2S clock (I2S_CKIN)
+
+Optional properties:
+- st,syscfg: phandle for pwrcfg, mandatory to disable/enable backup domain
+ write protection (RTC clock).
+
+Example:
+
+ rcc: reset-clock-controller@58024400 {
+ compatible = "st,stm32h743-rcc", "st,stm32-rcc";
+ reg = <0x58024400 0x400>;
+ #reset-cells = <1>;
+ #clock-cells = <2>;
+ clocks = <&clk_hse>, <&clk_lse>, <&clk_i2s_ckin>;
+
+ st,syscfg = <&pwrcfg>;
+};
+
+The peripheral clock consumer should specify the desired clock by
+having the clock ID in its "clocks" phandle cell.
+
+Example:
+
+ timer5: timer@40000c00 {
+ compatible = "st,stm32-timer";
+ reg = <0x40000c00 0x400>;
+ interrupts = <50>;
+ clocks = <&rcc TIM5_CK>;
+ };
+
+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 = AHB4RSTR_offset / 4 * 32 + CRCRST_bit_offset = 0x88 / 4 * 32 + 19 = 1107
+
+Example:
+
+ timer2 {
+ resets = <&rcc STM32H7_APB1L_RESET(TIM2)>;
+ };