dm: reset: add stm32 reset driver

This driver is adapted from linux drivers/reset/reset-stm32.c
It's compatible with STM32 F4/F7/H7 SoCs.

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

To add support for each SoC family, a SoC's specific
include/dt-binfings/mfd/stm32xx-rcc.h file must be added.

This patch only includes stm32h7-rcc.h dedicated for STM32H7 SoCs.
Other SoCs support will be added in the future.

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

doc/device-tree-bindings/reset/st,stm32-rcc.txt

@@ -0,0 +1,6 @@
+STMicroelectronics STM32 Peripheral Reset Controller
+====================================================
+
+The RCC IP is both a reset and a clock controller.
+
+Please see Documentation/devicetree/bindings/clock/st,stm32-rcc.txt

drivers/reset/Kconfig

@@ -28,6 +28,13 @@ config STI_RESET
 	  Say Y if you want to control reset signals provided by system config
 	  block.
 
+config STM32_RESET
+	bool "Enable the STM32 reset"
+	depends on STM32
+	help
+	  Support for reset controllers on STMicroelectronics STM32 family SoCs.
+	  This resset driver is compatible with STM32 F4/F7 and H7 SoCs.
+
 config TEGRA_CAR_RESET
 	bool "Enable Tegra CAR-based reset driver"
 	depends on TEGRA_CAR

drivers/reset/Makefile

@@ -6,6 +6,7 @@ obj-$(CONFIG_DM_RESET) += reset-uclass.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-reset.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-reset-test.o
 obj-$(CONFIG_STI_RESET) += sti-reset.o
+obj-$(CONFIG_STM32_RESET) += stm32-reset.o
 obj-$(CONFIG_TEGRA_CAR_RESET) += tegra-car-reset.o
 obj-$(CONFIG_TEGRA186_RESET) += tegra186-reset.o
 obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o

drivers/reset/stm32-reset.c

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author(s): Patrice CHOTARD, <patrice.chotard@st.com> for STMicroelectronics.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <reset-uclass.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct stm32_reset_priv {
+	fdt_addr_t base;
+};
+
+static int stm32_reset_request(struct reset_ctl *reset_ctl)
+{
+	return 0;
+}
+
+static int stm32_reset_free(struct reset_ctl *reset_ctl)
+{
+	return 0;
+}
+
+static int stm32_reset_assert(struct reset_ctl *reset_ctl)
+{
+	struct stm32_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	int bank = (reset_ctl->id / BITS_PER_LONG) * 4;
+	int offset = reset_ctl->id % BITS_PER_LONG;
+	debug("%s: reset id = %ld bank = %d offset = %d)\n", __func__,
+	      reset_ctl->id, bank, offset);
+
+	setbits_le32(priv->base + bank, BIT(offset));
+
+	return 0;
+}
+
+static int stm32_reset_deassert(struct reset_ctl *reset_ctl)
+{
+	struct stm32_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	int bank = (reset_ctl->id / BITS_PER_LONG) * 4;
+	int offset = reset_ctl->id % BITS_PER_LONG;
+	debug("%s: reset id = %ld bank = %d offset = %d)\n", __func__,
+	      reset_ctl->id, bank, offset);
+
+	clrbits_le32(priv->base + bank, BIT(offset));
+
+	return 0;
+}
+
+static const struct reset_ops stm32_reset_ops = {
+	.request	= stm32_reset_request,
+	.free		= stm32_reset_free,
+	.rst_assert	= stm32_reset_assert,
+	.rst_deassert	= stm32_reset_deassert,
+};
+
+static int stm32_reset_probe(struct udevice *dev)
+{
+	struct stm32_reset_priv *priv = dev_get_priv(dev);
+
+	priv->base = devfdt_get_addr(dev);
+	if (priv->base == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(stm32_rcc_reset) = {
+	.name			= "stm32_rcc_reset",
+	.id			= UCLASS_RESET,
+	.probe			= stm32_reset_probe,
+	.priv_auto_alloc_size	= sizeof(struct stm32_reset_priv),
+	.ops			= &stm32_reset_ops,
+};

include/dt-bindings/mfd/stm32h7-rcc.h

@@ -0,0 +1,138 @@
+/*
+ * This header provides constants for the STM32H7 RCC IP
+ */
+
+#ifndef _DT_BINDINGS_MFD_STM32H7_RCC_H
+#define _DT_BINDINGS_MFD_STM32H7_RCC_H
+
+/* AHB3 */
+#define STM32H7_RCC_AHB3_MDMA		0
+#define STM32H7_RCC_AHB3_DMA2D		4
+#define STM32H7_RCC_AHB3_JPGDEC		5
+#define STM32H7_RCC_AHB3_FMC		12
+#define STM32H7_RCC_AHB3_QUADSPI	14
+#define STM32H7_RCC_AHB3_SDMMC1		16
+#define STM32H7_RCC_AHB3_CPU1		31
+
+#define STM32H7_AHB3_RESET(bit) (STM32H7_RCC_AHB3_##bit + (0x7C * 8))
+
+/* AHB1 */
+#define STM32H7_RCC_AHB1_DMA1		0
+#define STM32H7_RCC_AHB1_DMA2		1
+#define STM32H7_RCC_AHB1_ADC12		5
+#define STM32H7_RCC_AHB1_ART		14
+#define STM32H7_RCC_AHB1_ETH1MAC	15
+#define STM32H7_RCC_AHB1_USB1OTG	25
+#define STM32H7_RCC_AHB1_USB2OTG	27
+#define STM32H7_RCC_AHB1_CPU2		31
+
+#define STM32H7_AHB1_RESET(bit) (STM32H7_RCC_AHB1_##bit + (0x80 * 8))
+
+/* AHB2 */
+#define STM32H7_RCC_AHB2_CAMITF		0
+#define STM32H7_RCC_AHB2_CRYPT		4
+#define STM32H7_RCC_AHB2_HASH		5
+#define STM32H7_RCC_AHB2_RNG		6
+#define STM32H7_RCC_AHB2_SDMMC2		9
+
+#define STM32H7_AHB2_RESET(bit) (STM32H7_RCC_AHB2_##bit + (0x84 * 8))
+
+/* AHB4 */
+#define STM32H7_RCC_AHB4_GPIOA		0
+#define STM32H7_RCC_AHB4_GPIOB		1
+#define STM32H7_RCC_AHB4_GPIOC		2
+#define STM32H7_RCC_AHB4_GPIOD		3
+#define STM32H7_RCC_AHB4_GPIOE		4
+#define STM32H7_RCC_AHB4_GPIOF		5
+#define STM32H7_RCC_AHB4_GPIOG		6
+#define STM32H7_RCC_AHB4_GPIOH		7
+#define STM32H7_RCC_AHB4_GPIOI		8
+#define STM32H7_RCC_AHB4_GPIOJ		9
+#define STM32H7_RCC_AHB4_GPIOK		10
+#define STM32H7_RCC_AHB4_CRC		19
+#define STM32H7_RCC_AHB4_BDMA		21
+#define STM32H7_RCC_AHB4_ADC3		24
+#define STM32H7_RCC_AHB4_HSEM		25
+
+#define STM32H7_AHB4_RESET(bit) (STM32H7_RCC_AHB4_##bit + (0x88 * 8))
+
+
+/* APB3 */
+#define STM32H7_RCC_APB3_LTDC		3
+#define STM32H7_RCC_APB3_DSI		4
+
+#define STM32H7_APB3_RESET(bit) (STM32H7_RCC_APB3_##bit + (0x8C * 8))
+
+/* APB1L */
+#define STM32H7_RCC_APB1L_TIM2		0
+#define STM32H7_RCC_APB1L_TIM3		1
+#define STM32H7_RCC_APB1L_TIM4		2
+#define STM32H7_RCC_APB1L_TIM5		3
+#define STM32H7_RCC_APB1L_TIM6		4
+#define STM32H7_RCC_APB1L_TIM7		5
+#define STM32H7_RCC_APB1L_TIM12		6
+#define STM32H7_RCC_APB1L_TIM13		7
+#define STM32H7_RCC_APB1L_TIM14		8
+#define STM32H7_RCC_APB1L_LPTIM1	9
+#define STM32H7_RCC_APB1L_SPI2		14
+#define STM32H7_RCC_APB1L_SPI3		15
+#define STM32H7_RCC_APB1L_SPDIF_RX	16
+#define STM32H7_RCC_APB1L_USART2	17
+#define STM32H7_RCC_APB1L_USART3	18
+#define STM32H7_RCC_APB1L_UART4		19
+#define STM32H7_RCC_APB1L_UART5		20
+#define STM32H7_RCC_APB1L_I2C1		21
+#define STM32H7_RCC_APB1L_I2C2		22
+#define STM32H7_RCC_APB1L_I2C3		23
+#define STM32H7_RCC_APB1L_HDMICEC	27
+#define STM32H7_RCC_APB1L_DAC12		29
+#define STM32H7_RCC_APB1L_USART7	30
+#define STM32H7_RCC_APB1L_USART8	31
+
+#define STM32H7_APB1L_RESET(bit) (STM32H7_RCC_APB1L_##bit + (0x90 * 8))
+
+/* APB1H */
+#define STM32H7_RCC_APB1H_CRS		1
+#define STM32H7_RCC_APB1H_SWP		2
+#define STM32H7_RCC_APB1H_OPAMP		4
+#define STM32H7_RCC_APB1H_MDIOS		5
+#define STM32H7_RCC_APB1H_FDCAN		8
+
+#define STM32H7_APB1H_RESET(bit) (STM32H7_RCC_APB1H_##bit + (0x94 * 8))
+
+/* APB2 */
+#define STM32H7_RCC_APB2_TIM1		0
+#define STM32H7_RCC_APB2_TIM8		1
+#define STM32H7_RCC_APB2_USART1		4
+#define STM32H7_RCC_APB2_USART6		5
+#define STM32H7_RCC_APB2_SPI1		12
+#define STM32H7_RCC_APB2_SPI4		13
+#define STM32H7_RCC_APB2_TIM15		16
+#define STM32H7_RCC_APB2_TIM16		17
+#define STM32H7_RCC_APB2_TIM17		18
+#define STM32H7_RCC_APB2_SPI5		20
+#define STM32H7_RCC_APB2_SAI1		22
+#define STM32H7_RCC_APB2_SAI2		23
+#define STM32H7_RCC_APB2_SAI3		24
+#define STM32H7_RCC_APB2_DFSDM1		28
+#define STM32H7_RCC_APB2_HRTIM		29
+
+#define STM32H7_APB2_RESET(bit) (STM32H7_RCC_APB2_##bit + (0x98 * 8))
+
+/* APB4 */
+#define STM32H7_RCC_APB4_SYSCFG		1
+#define STM32H7_RCC_APB4_LPUART1	3
+#define STM32H7_RCC_APB4_SPI6		5
+#define STM32H7_RCC_APB4_I2C4		7
+#define STM32H7_RCC_APB4_LPTIM2		9
+#define STM32H7_RCC_APB4_LPTIM3		10
+#define STM32H7_RCC_APB4_LPTIM4		11
+#define STM32H7_RCC_APB4_LPTIM5		12
+#define STM32H7_RCC_APB4_COMP12		14
+#define STM32H7_RCC_APB4_VREF		15
+#define STM32H7_RCC_APB4_SAI4		21
+#define STM32H7_RCC_APB4_TMPSENS	26
+
+#define STM32H7_APB4_RESET(bit) (STM32H7_RCC_APB4_##bit + (0x9C * 8))
+
+#endif /* _DT_BINDINGS_MFD_STM32H7_RCC_H */