[PATCH v3 0/4] Add STM32 Reset Driver

[PATCH v3 0/4] Add STM32 Reset Driver

[gabriel.fernandez at st.com]

From: Gabriel Fernandez <gabriel.fernandez@st.com>

v3:
 - Use the builtin for the register

v2:
 - switch to the non-relaxed variants
 - describe dt-binfings in one place

The STM32 MCUs family IPs can be reset by accessing some registers
from the RCC block.

Gabriel Fernandez (1):
  ARM: dts: stm32f429: add missing #reset-cells of rcc

Maxime Coquelin (3):
  dt-bindings: mfd: Add STM32F4 RCC numeric constants into DT include
    file
  dt-bindings: Document the STM32 reset bindings
  drivers: reset: Add STM32 reset driver

 .../devicetree/bindings/clock/st,stm32-rcc.txt     |  42 ++++++--
 .../devicetree/bindings/reset/st,stm32-rcc.txt     |   6 ++
 arch/arm/boot/dts/stm32f429.dtsi                   |   1 +
 drivers/reset/Makefile                             |   1 +
 drivers/reset/reset-stm32.c                        | 108 +++++++++++++++++++++
 include/dt-bindings/mfd/stm32f4-rcc.h              |  98 +++++++++++++++++++
 6 files changed, 249 insertions(+), 7 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
 create mode 100644 drivers/reset/reset-stm32.c
 create mode 100644 include/dt-bindings/mfd/stm32f4-rcc.h

-- 
1.9.1

[PATCH v3 1/4] dt-bindings: mfd: Add STM32F4 RCC numeric constants into DT include file

[gabriel.fernandez at st.com]

From: Maxime Coquelin <mcoquelin.stm32@gmail.com>

Ths patch lists STM32F4's RCC numeric constants.
It will be used by clock and reset drivers, and DT bindings.

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
---
 include/dt-bindings/mfd/stm32f4-rcc.h | 98 +++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 include/dt-bindings/mfd/stm32f4-rcc.h

diff --git a/include/dt-bindings/mfd/stm32f4-rcc.h b/include/dt-bindings/mfd/stm32f4-rcc.h
new file mode 100644
index 0000000..e98942dc
--- /dev/null
+++ b/include/dt-bindings/mfd/stm32f4-rcc.h
@@ -0,0 +1,98 @@
+/*
+ * This header provides constants for the STM32F4 RCC IP
+ */
+
+#ifndef _DT_BINDINGS_MFD_STM32F4_RCC_H
+#define _DT_BINDINGS_MFD_STM32F4_RCC_H
+
+/* AHB1 */
+#define STM32F4_RCC_AHB1_GPIOA	0
+#define STM32F4_RCC_AHB1_GPIOB	1
+#define STM32F4_RCC_AHB1_GPIOC	2
+#define STM32F4_RCC_AHB1_GPIOD	3
+#define STM32F4_RCC_AHB1_GPIOE	4
+#define STM32F4_RCC_AHB1_GPIOF	5
+#define STM32F4_RCC_AHB1_GPIOG	6
+#define STM32F4_RCC_AHB1_GPIOH	7
+#define STM32F4_RCC_AHB1_GPIOI	8
+#define STM32F4_RCC_AHB1_GPIOJ	9
+#define STM32F4_RCC_AHB1_GPIOK	10
+#define STM32F4_RCC_AHB1_CRC	12
+#define STM32F4_RCC_AHB1_DMA1	21
+#define STM32F4_RCC_AHB1_DMA2	22
+#define STM32F4_RCC_AHB1_DMA2D	23
+#define STM32F4_RCC_AHB1_ETHMAC	25
+#define STM32F4_RCC_AHB1_OTGHS	29
+
+#define STM32F4_AHB1_RESET(bit) (STM32F4_RCC_AHB1_##bit + (0x10 * 8))
+#define STM32F4_AHB1_CLOCK(bit) (STM32F4_RCC_AHB1_##bit + (0x30 * 8))
+
+
+/* AHB2 */
+#define STM32F4_RCC_AHB2_DCMI	0
+#define STM32F4_RCC_AHB2_CRYP	4
+#define STM32F4_RCC_AHB2_HASH	5
+#define STM32F4_RCC_AHB2_RNG	6
+#define STM32F4_RCC_AHB2_OTGFS	7
+
+#define STM32F4_AHB2_RESET(bit)	(STM32F4_RCC_AHB2_##bit + (0x14 * 8))
+#define STM32F4_AHB2_CLOCK(bit)	(STM32F4_RCC_AHB2_##bit + (0x34 * 8))
+
+/* AHB3 */
+#define STM32F4_RCC_AHB3_FMC	0
+
+#define STM32F4_AHB3_RESET(bit)	(STM32F4_RCC_AHB3_##bit + (0x18 * 8))
+#define STM32F4_AHB3_CLOCK(bit)	(STM32F4_RCC_AHB3_##bit + (0x38 * 8))
+
+/* APB1 */
+#define STM32F4_RCC_APB1_TIM2	0
+#define STM32F4_RCC_APB1_TIM3	1
+#define STM32F4_RCC_APB1_TIM4	2
+#define STM32F4_RCC_APB1_TIM5	3
+#define STM32F4_RCC_APB1_TIM6	4
+#define STM32F4_RCC_APB1_TIM7	5
+#define STM32F4_RCC_APB1_TIM12	6
+#define STM32F4_RCC_APB1_TIM13	7
+#define STM32F4_RCC_APB1_TIM14	8
+#define STM32F4_RCC_APB1_WWDG	11
+#define STM32F4_RCC_APB1_SPI2	14
+#define STM32F4_RCC_APB1_SPI3	15
+#define STM32F4_RCC_APB1_UART2	17
+#define STM32F4_RCC_APB1_UART3	18
+#define STM32F4_RCC_APB1_UART4	19
+#define STM32F4_RCC_APB1_UART5	20
+#define STM32F4_RCC_APB1_I2C1	21
+#define STM32F4_RCC_APB1_I2C2	22
+#define STM32F4_RCC_APB1_I2C3	23
+#define STM32F4_RCC_APB1_CAN1	25
+#define STM32F4_RCC_APB1_CAN2	26
+#define STM32F4_RCC_APB1_PWR	28
+#define STM32F4_RCC_APB1_DAC	29
+#define STM32F4_RCC_APB1_UART7	30
+#define STM32F4_RCC_APB1_UART8	31
+
+#define STM32F4_APB1_RESET(bit)	(STM32F4_RCC_APB1_##bit + (0x20 * 8))
+#define STM32F4_APB1_CLOCK(bit)	(STM32F4_RCC_APB1_##bit + (0x40 * 8))
+
+/* APB2 */
+#define STM32F4_RCC_APB2_TIM1	0
+#define STM32F4_RCC_APB2_TIM8	1
+#define STM32F4_RCC_APB2_USART1	4
+#define STM32F4_RCC_APB2_USART6	5
+#define STM32F4_RCC_APB2_ADC	8
+#define STM32F4_RCC_APB2_SDIO	11
+#define STM32F4_RCC_APB2_SPI1	12
+#define STM32F4_RCC_APB2_SPI4	13
+#define STM32F4_RCC_APB2_SYSCFG	14
+#define STM32F4_RCC_APB2_TIM9	16
+#define STM32F4_RCC_APB2_TIM10	17
+#define STM32F4_RCC_APB2_TIM11	18
+#define STM32F4_RCC_APB2_SPI5	20
+#define STM32F4_RCC_APB2_SPI6	21
+#define STM32F4_RCC_APB2_SAI1	22
+#define STM32F4_RCC_APB2_LTDC	26
+
+#define STM32F4_APB2_RESET(bit)	(STM32F4_RCC_APB2_##bit + (0x24 * 8))
+#define STM32F4_APB2_CLOCK(bit)	(STM32F4_RCC_APB2_##bit + (0x44 * 8))
+
+#endif /* _DT_BINDINGS_MFD_STM32F4_RCC_H */
-- 
1.9.1

[PATCH v3 2/4] dt-bindings: Document the STM32 reset bindings

[gabriel.fernandez at st.com]

From: Maxime Coquelin <mcoquelin.stm32@gmail.com>

This adds documentation of device tree bindings for the
STM32 reset controller.

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../devicetree/bindings/clock/st,stm32-rcc.txt     | 42 ++++++++++++++++++----
 .../devicetree/bindings/reset/st,stm32-rcc.txt     |  6 ++++
 2 files changed, 41 insertions(+), 7 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-rcc.txt

diff --git a/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt b/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt
index fee3205..c209de6 100644
--- a/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt
+++ b/Documentation/devicetree/bindings/clock/st,stm32-rcc.txt
@@ -1,16 +1,16 @@
 STMicroelectronics STM32 Reset and Clock Controller
 ===================================================
 
-The RCC IP is both a reset and a clock controller. This documentation only
-describes the clock part.
+The RCC IP is both a reset and a clock controller.
 
-Please also refer to clock-bindings.txt in this directory for common clock
-controller binding usage.
+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"
 - 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
@@ -19,6 +19,7 @@ Required properties:
 Example:
 
 	rcc: rcc at 40023800 {
+		#reset-cells = <1>;
 		#clock-cells = <2>
 		compatible = "st,stm32f42xx-rcc", "st,stm32-rcc";
 		reg = <0x40023800 0x400>;
@@ -35,16 +36,23 @@ 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 0>
+		clocks = <&rcc 0 STM32F4_AHB1_CLOCK(GPIOA)>
 	};
 
 	/* Gated clock, AHB2 bit 4 (CRYP) */
 	... {
-		clocks = <&rcc 0 36>
+		clocks = <&rcc 0 STM32F4_AHB2_CLOCK(CRYP)>
 	};
 
 Specifying other clocks
@@ -61,5 +69,25 @@ Example:
 
 	/* Misc clock, FCLK */
 	... {
-		clocks = <&rcc 1 1>
+		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)>;
 	};
diff --git a/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt b/Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
new file mode 100644
index 0000000..01db343
--- /dev/null
+++ b/Documentation/devicetree/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
-- 
1.9.1

[PATCH v3 3/4] drivers: reset: Add STM32 reset driver

[gabriel.fernandez at st.com]

From: Maxime Coquelin <mcoquelin.stm32@gmail.com>

The STM32 MCUs family IPs can be reset by accessing some registers
from the RCC block.

The list of available reset lines is documented in the DT bindings.

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
---
 drivers/reset/Makefile      |   1 +
 drivers/reset/reset-stm32.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 drivers/reset/reset-stm32.c

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 5d65a93..64ebb0c 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
 obj-$(CONFIG_MACH_PISTACHIO) += reset-pistachio.o
 obj-$(CONFIG_ARCH_MESON) += reset-meson.o
+obj-$(CONFIG_ARCH_STM32) += reset-stm32.o
 obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_ARCH_STI) += sti/
 obj-$(CONFIG_ARCH_HISI) += hisilicon/
diff --git a/drivers/reset/reset-stm32.c b/drivers/reset/reset-stm32.c
new file mode 100644
index 0000000..3a7c8527
--- /dev/null
+++ b/drivers/reset/reset-stm32.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) Maxime Coquelin 2015
+ * Author:  Maxime Coquelin <mcoquelin.stm32@gmail.com>
+ * License terms:  GNU General Public License (GPL), version 2
+ *
+ * Heavily based on sunxi driver from Maxime Ripard.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+struct stm32_reset_data {
+	spinlock_t			lock;
+	void __iomem			*membase;
+	struct reset_controller_dev	rcdev;
+};
+
+static int stm32_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct stm32_reset_data *data = container_of(rcdev,
+						     struct stm32_reset_data,
+						     rcdev);
+	int bank = id / BITS_PER_LONG;
+	int offset = id % BITS_PER_LONG;
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	reg = readl(data->membase + (bank * 4));
+	writel(reg | BIT(offset), data->membase + (bank * 4));
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	struct stm32_reset_data *data = container_of(rcdev,
+						     struct stm32_reset_data,
+						     rcdev);
+	int bank = id / BITS_PER_LONG;
+	int offset = id % BITS_PER_LONG;
+	unsigned long flags;
+	u32 reg;
+
+	spin_lock_irqsave(&data->lock, flags);
+
+	reg = readl(data->membase + (bank * 4));
+	writel(reg & ~BIT(offset), data->membase + (bank * 4));
+
+	spin_unlock_irqrestore(&data->lock, flags);
+
+	return 0;
+}
+
+static const struct reset_control_ops stm32_reset_ops = {
+	.assert		= stm32_reset_assert,
+	.deassert	= stm32_reset_deassert,
+};
+
+static const struct of_device_id stm32_reset_dt_ids[] = {
+	 { .compatible = "st,stm32-rcc", },
+	 { /* sentinel */ },
+};
+
+static int stm32_reset_probe(struct platform_device *pdev)
+{
+	struct stm32_reset_data *data;
+	struct resource *res;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	data->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(data->membase))
+		return PTR_ERR(data->membase);
+
+	spin_lock_init(&data->lock);
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = resource_size(res) * 8;
+	data->rcdev.ops = &stm32_reset_ops;
+	data->rcdev.of_node = pdev->dev.of_node;
+
+	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+}
+
+static struct platform_driver stm32_reset_driver = {
+	.probe	= stm32_reset_probe,
+	.driver = {
+		.name		= "stm32-rcc-reset",
+		.of_match_table	= stm32_reset_dt_ids,
+	},
+};
+builtin_platform_driver(stm32_reset_driver);
-- 
1.9.1

[PATCH v3 4/4] ARM: dts: stm32f429: add missing #reset-cells of rcc

[gabriel.fernandez at st.com]

From: Gabriel Fernandez <gabriel.fernandez@st.com>

This patch adds #reset-cells property to rcc node.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
---
 arch/arm/boot/dts/stm32f429.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index 35df462..fe89236 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -326,6 +326,7 @@
 		};
 
 		rcc: rcc at 40023810 {
+			#reset-cells = <1>;
 			#clock-cells = <2>;
 			compatible = "st,stm32f42xx-rcc", "st,stm32-rcc";
 			reg = <0x40023800 0x400>;
-- 
1.9.1

[PATCH v3 0/4] Add STM32 Reset Driver

[Philipp Zabel]

Am Freitag, den 22.07.2016, 11:37 +0200 schrieb
gabriel.fernandez at st.com:
> From: Gabriel Fernandez <gabriel.fernandez@st.com>
> 
> v3:
>  - Use the builtin for the register
> 
> v2:
>  - switch to the non-relaxed variants
>  - describe dt-binfings in one place
> 
> The STM32 MCUs family IPs can be reset by accessing some registers
> from the RCC block.
> 
> Gabriel Fernandez (1):
>   ARM: dts: stm32f429: add missing #reset-cells of rcc
> 
> Maxime Coquelin (3):
>   dt-bindings: mfd: Add STM32F4 RCC numeric constants into DT include
>     file
>   dt-bindings: Document the STM32 reset bindings
>   drivers: reset: Add STM32 reset driver
> 
>  .../devicetree/bindings/clock/st,stm32-rcc.txt     |  42 ++++++--
>  .../devicetree/bindings/reset/st,stm32-rcc.txt     |   6 ++
>  arch/arm/boot/dts/stm32f429.dtsi                   |   1 +
>  drivers/reset/Makefile                             |   1 +
>  drivers/reset/reset-stm32.c                        | 108 +++++++++++++++++++++
>  include/dt-bindings/mfd/stm32f4-rcc.h              |  98 +++++++++++++++++++
>  6 files changed, 249 insertions(+), 7 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/reset/st,stm32-rcc.txt
>  create mode 100644 drivers/reset/reset-stm32.c
>  create mode 100644 include/dt-bindings/mfd/stm32f4-rcc.h

Thank you, I've applied all four patches.

regards
Philipp