dm: clk: add clk driver support for stm32h7 SoCs

This driver implements basic clock setup, only clock gating
is implemented.

This driver doesn't implement .of_match as it's binded
by MFD RCC driver.

Files include/dt-bindings/clock/stm32h7-clks.h and
doc/device-tree-bindings/clock/st,stm32h7-rcc.txt
will be available soon in a kernel tag, as all the
bindings have been acked by Rob Herring [1].

[1] http://lkml.iu.edu/hypermail/linux/kernel/1704.0/00935.html



Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/device-tree-bindings/clock/st,stm32h7-rcc.txt

+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)
+
+- st,syscfg: phandle for pwrcfg, mandatory to disable/enable backup domain
+  write protection (RTC clock).
+
+- pll x node: Allow to register a pll with specific parameters.
+  Please see PLL section below.
+
+Example:
+
+	rcc: rcc@58024400 {
+		#reset-cells = <1>;
+		#clock-cells = <2>
+		compatible = "st,stm32h743-rcc", "st,stm32-rcc";
+		reg = <0x58024400 0x400>;
+		clocks = <&clk_hse>, <&clk_lse>, <&clk_i2s_ckin>;
+
+		st,syscfg = <&pwrcfg>;
+
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		vco1@58024430 {
+			#clock-cells = <0>;
+			compatible = "stm32,pll";
+			reg = <0>;
+		};
+
+		vco2@58024438 {
+			#clock-cells = <0>;
+			compatible = "stm32,pll";
+			reg = <1>;
+			st,clock-div = <2>;
+			st,clock-mult = <40>;
+			st,frac-status = <0>;
+			st,frac = <0>;
+			st,vcosel = <1>;
+			st,pllrge = <2>;
+		};
+	};
+
+
+STM32H7 PLL
+-----------
+
+The VCO of STM32 PLL could be reprensented like this:
+
+  Vref    ---------       --------
+    ---->| / DIVM  |---->| x DIVN | ------> VCO
+          ---------       --------
+		             ^
+			     |
+	                  -------
+		         | FRACN |
+		          -------
+
+When the PLL is configured in integer mode:
+- VCO = ( Vref / DIVM ) * DIVN
+
+When the PLL is configured in fractional mode:
+- VCO = ( Vref / DIVM ) * ( DIVN + FRACN / 2^13)
+
+
+Required properties for pll node:
+- compatible: Should be:
+  "stm32,pll"
+
+- #clock-cells: from common clock binding; shall be set to 0
+- reg: Should be the pll number.
+
+Optional properties:
+- st,clock-div:  DIVM division factor       : <1..63>
+- st,clock-mult: DIVN multiplication factor : <4..512>
+
+- st,frac-status:
+   - 0 Pll is configured in integer mode
+   - 1 Pll is configure in fractional mode
+
+- st,frac: Fractional part of the multiplication factor : <0..8191>
+
+- st,vcosel: VCO selection
+  - 0: Wide VCO range:192 to 836 MHz
+  - 1: Medium VCO range:150 to 420 MHz
+
+- st,pllrge: PLL input frequency range
+  - 0: The PLL input (Vref / DIVM) clock range frequency is between 1 and 2 MHz
+  - 1: The PLL input (Vref / DIVM) clock range frequency is between 2 and 4 MHz
+  - 2: The PLL input (Vref / DIVM) clock range frequency is between 4 and 8 MHz
+  - 3: The PLL input (Vref / DIVM) clock range frequency is between 8 and 16 MHz
+
+
+The peripheral clock consumer should specify the desired clock by
+having the clock ID in its "clocks" phandle cell.
+
+All available clocks are defined as preprocessor macros in
+dt-bindings/clock/stm32h7-clks.h header and can be used in device
+tree sources.
+
+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
+
+All available preprocessor macros for reset are defined dt-bindings//mfd/stm32h7-rcc.h
+header and can be used in device tree sources.
+
+example:
+
+	timer2 {
+		resets	= <&rcc STM32H7_APB1L_RESET(TIM2)>;
+	};

drivers/clk/Makefile

@@ -22,3 +22,4 @@ obj-$(CONFIG_CLK_BCM6345) += clk_bcm6345.o
 obj-$(CONFIG_CLK_BOSTON) += clk_boston.o
 obj-$(CONFIG_ARCH_ASPEED) += aspeed/
 obj-$(CONFIG_STM32F7) += clk_stm32f7.o
+obj-$(CONFIG_STM32H7) += clk_stm32h7.o

include/dt-bindings/clock/stm32h7-clks.h

+/* SYS, CORE AND BUS CLOCKS */
+#define SYS_D1CPRE 0
+#define HCLK 1
+#define PCLK1 2
+#define PCLK2 3
+#define PCLK3 4
+#define PCLK4 5
+#define HSI_DIV 6
+#define HSE_1M 7
+#define I2S_CKIN 8
+#define CK_DSI_PHY 9
+#define HSE_CK 10
+#define LSE_CK 11
+#define CSI_KER_DIV122 12
+#define RTC_CK 13
+#define CPU_SYSTICK 14
+
+/* OSCILLATOR BANK */
+#define OSC_BANK 18
+#define HSI_CK 18
+#define HSI_KER_CK 19
+#define CSI_CK 20
+#define CSI_KER_CK 21
+#define RC48_CK 22
+#define LSI_CK 23
+
+/* MCLOCK BANK */
+#define MCLK_BANK 28
+#define PER_CK 28
+#define PLLSRC 29
+#define SYS_CK 30
+#define TRACEIN_CK 31
+
+/* ODF BANK */
+#define ODF_BANK 32
+#define PLL1_P 32
+#define PLL1_Q 33
+#define PLL1_R 34
+#define PLL2_P 35
+#define PLL2_Q 36
+#define PLL2_R 37
+#define PLL3_P 38
+#define PLL3_Q 39
+#define PLL3_R 40
+
+/* MCO BANK */
+#define MCO_BANK 41
+#define MCO1 41
+#define MCO2 42
+
+/* PERIF BANK */
+#define PERIF_BANK 50
+#define D1SRAM1_CK 50
+#define ITCM_CK 51
+#define DTCM2_CK 52
+#define DTCM1_CK 53
+#define FLITF_CK 54
+#define JPGDEC_CK 55
+#define DMA2D_CK 56
+#define MDMA_CK 57
+#define USB2ULPI_CK 58
+#define USB1ULPI_CK 59
+#define ETH1RX_CK 60
+#define ETH1TX_CK 61
+#define ETH1MAC_CK 62
+#define ART_CK 63
+#define DMA2_CK 64
+#define DMA1_CK 65
+#define D2SRAM3_CK 66
+#define D2SRAM2_CK 67
+#define D2SRAM1_CK 68
+#define HASH_CK 69
+#define CRYPT_CK 70
+#define CAMITF_CK 71
+#define BKPRAM_CK 72
+#define HSEM_CK 73
+#define BDMA_CK 74
+#define CRC_CK 75
+#define GPIOK_CK 76
+#define GPIOJ_CK 77
+#define GPIOI_CK 78
+#define GPIOH_CK 79
+#define GPIOG_CK 80
+#define GPIOF_CK 81
+#define GPIOE_CK 82
+#define GPIOD_CK 83
+#define GPIOC_CK 84
+#define GPIOB_CK 85
+#define GPIOA_CK 86
+#define WWDG1_CK 87
+#define DAC12_CK 88
+#define WWDG2_CK 89
+#define TIM14_CK 90
+#define TIM13_CK 91
+#define TIM12_CK 92
+#define TIM7_CK 93
+#define TIM6_CK 94
+#define TIM5_CK 95
+#define TIM4_CK 96
+#define TIM3_CK 97
+#define TIM2_CK 98
+#define MDIOS_CK 99
+#define OPAMP_CK 100
+#define CRS_CK 101
+#define TIM17_CK 102
+#define TIM16_CK 103
+#define TIM15_CK 104
+#define TIM8_CK 105
+#define TIM1_CK 106
+#define TMPSENS_CK 107
+#define RTCAPB_CK 108
+#define VREF_CK 109
+#define COMP12_CK 110
+#define SYSCFG_CK 111
+/* must be equal to last peripheral clock index */
+#define LAST_PERIF_BANK SYSCFG_CK
+
+/* KERNEL BANK */
+#define KERN_BANK 120
+#define SDMMC1_CK 120
+#define QUADSPI_CK 121
+#define FMC_CK 122
+#define USB2OTG_CK 123
+#define USB1OTG_CK 124
+#define ADC12_CK 125
+#define SDMMC2_CK 126
+#define RNG_CK 127
+#define ADC3_CK 128
+#define DSI_CK 129
+#define LTDC_CK 130
+#define USART8_CK 131
+#define USART7_CK 132
+#define HDMICEC_CK 133
+#define I2C3_CK 134
+#define I2C2_CK 135
+#define I2C1_CK 136
+#define UART5_CK 137
+#define UART4_CK 138
+#define USART3_CK 139
+#define USART2_CK 140
+#define SPDIFRX_CK 141
+#define SPI3_CK 142
+#define SPI2_CK 143
+#define LPTIM1_CK 144
+#define FDCAN_CK 145
+#define SWP_CK 146
+#define HRTIM_CK 147
+#define DFSDM1_CK 148
+#define SAI3_CK 149
+#define SAI2_CK 150
+#define SAI1_CK 151
+#define SPI5_CK 152
+#define SPI4_CK 153
+#define SPI1_CK 154
+#define USART6_CK 155
+#define USART1_CK 156
+#define SAI4B_CK 157
+#define SAI4A_CK 158
+#define LPTIM5_CK 159
+#define LPTIM4_CK 160
+#define LPTIM3_CK 161
+#define LPTIM2_CK 162
+#define I2C4_CK 163
+#define SPI6_CK 164
+#define LPUART1_CK 165
+
+#define STM32H7_MAX_CLKS 166