[PATCH v3 0/2] reset driver for NXP LPC18xx family

[PATCH v3 0/2] reset driver for NXP LPC18xx family

[Joachim Eastwood]

This patch set adds a reset driver for NXP LPC18xx/43xx devices.

Changes in v3:
* add patch descriptions
* change parameter name in to_rgu_data macro to avoid a potential
  issue if code is changed.

Changes in v2:
* clean up header includes
* prefix M0 reset defines with LPC43XX
* fix comment about M0 reset lines
* reorganize reset call chains
* add reset number table to dt doc

There are no dependencies in this patch set. The DTS changes will
be sent separately to arm-soc once this patch set goes upstream.

Base support for the NXP LPC18xx family can be found here:
http://marc.info/?l=linux-arm-kernel&m=143016894704253&w=2

Joachim Eastwood (2):
  reset: add driver for lpc18xx rgu
  doc: dt: add documentation for lpc1850-rgu reset driver

 .../devicetree/bindings/reset/nxp,lpc1850-rgu.txt  |  84 +++++++
 drivers/reset/Makefile                             |   1 +
 drivers/reset/reset-lpc18xx.c                      | 258 +++++++++++++++++++++
 3 files changed, 343 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/nxp,lpc1850-rgu.txt
 create mode 100644 drivers/reset/reset-lpc18xx.c

-- 
1.8.0

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[PATCH v3 1/2] reset: add driver for lpc18xx rgu

[Joachim Eastwood]

Add reset driver for the Reset Generation Unit (RGU) found on NXP
LPC18xx and LPC43xx devies. This reset controller features up to 64
reset lines connected to different blocks and peripheral in the SoC.
Most reset lines on the controller are self clearing except for
those dealing with the Cortex-M0 cores on LPC43xx devices.

This driver also registers a restart handler that can be used to
reset the entire device.

Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/reset/Makefile        |   1 +
 drivers/reset/reset-lpc18xx.c | 258 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 259 insertions(+)
 create mode 100644 drivers/reset/reset-lpc18xx.c

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 157d421f755b..1d41feeb2dce 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_RESET_CONTROLLER) += core.o
+obj-$(CONFIG_ARCH_LPC18XX) += reset-lpc18xx.o
 obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
 obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
diff --git a/drivers/reset/reset-lpc18xx.c b/drivers/reset/reset-lpc18xx.c
new file mode 100644
index 000000000000..70922e9ac27f
--- /dev/null
+++ b/drivers/reset/reset-lpc18xx.c
@@ -0,0 +1,258 @@
+/*
+ * Reset driver for NXP LPC18xx/43xx Reset Generation Unit (RGU).
+ *
+ * Copyright (C) 2015 Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+/* LPC18xx RGU registers */
+#define LPC18XX_RGU_CTRL0		0x100
+#define LPC18XX_RGU_CTRL1		0x104
+#define LPC18XX_RGU_ACTIVE_STATUS0	0x150
+#define LPC18XX_RGU_ACTIVE_STATUS1	0x154
+
+#define LPC18XX_RGU_RESETS_PER_REG	32
+
+/* Internal reset outputs */
+#define LPC18XX_RGU_CORE_RST	0
+#define LPC43XX_RGU_M0SUB_RST	12
+#define LPC43XX_RGU_M0APP_RST	56
+
+struct lpc18xx_rgu_data {
+	struct reset_controller_dev rcdev;
+	struct clk *clk_delay;
+	struct clk *clk_reg;
+	void __iomem *base;
+	spinlock_t lock;
+	u32 delay_us;
+};
+
+#define to_rgu_data(p) container_of(p, struct lpc18xx_rgu_data, rcdev)
+
+static void __iomem *rgu_base;
+
+static int lpc18xx_rgu_restart(struct notifier_block *this, unsigned long mode,
+			       void *cmd)
+{
+	writel(BIT(LPC18XX_RGU_CORE_RST), rgu_base + LPC18XX_RGU_CTRL0);
+	mdelay(2000);
+
+	pr_emerg("%s: unable to restart system\n", __func__);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block lpc18xx_rgu_restart_nb = {
+	.notifier_call = lpc18xx_rgu_restart,
+	.priority = 192,
+};
+
+/*
+ * The LPC18xx RGU has mostly self-deasserting resets except for the
+ * two reset lines going to the internal Cortex-M0 cores.
+ *
+ * To prevent the M0 core resets from accidentally getting deasserted
+ * status register must be check and bits in control register set to
+ * preserve the state.
+ */
+static int lpc18xx_rgu_setclear_reset(struct reset_controller_dev *rcdev,
+				      unsigned long id, bool set)
+{
+	struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
+	u32 stat_offset = LPC18XX_RGU_ACTIVE_STATUS0;
+	u32 ctrl_offset = LPC18XX_RGU_CTRL0;
+	unsigned long flags;
+	u32 stat, rst_bit;
+
+	stat_offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
+	ctrl_offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
+	rst_bit = 1 << (id % LPC18XX_RGU_RESETS_PER_REG);
+
+	spin_lock_irqsave(&rc->lock, flags);
+	stat = ~readl(rc->base + stat_offset);
+	if (set)
+		writel(stat | rst_bit, rc->base + ctrl_offset);
+	else
+		writel(stat & ~rst_bit, rc->base + ctrl_offset);
+	spin_unlock_irqrestore(&rc->lock, flags);
+
+	return 0;
+}
+
+static int lpc18xx_rgu_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	return lpc18xx_rgu_setclear_reset(rcdev, id, true);
+}
+
+static int lpc18xx_rgu_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return lpc18xx_rgu_setclear_reset(rcdev, id, false);
+}
+
+/* Only M0 cores require explicit reset deassert */
+static int lpc18xx_rgu_reset(struct reset_controller_dev *rcdev,
+			     unsigned long id)
+{
+	struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
+
+	lpc18xx_rgu_assert(rcdev, id);
+	udelay(rc->delay_us);
+
+	switch (id) {
+	case LPC43XX_RGU_M0SUB_RST:
+	case LPC43XX_RGU_M0APP_RST:
+		lpc18xx_rgu_setclear_reset(rcdev, id, false);
+	}
+
+	return 0;
+}
+
+static int lpc18xx_rgu_status(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct lpc18xx_rgu_data *rc = to_rgu_data(rcdev);
+	u32 bit, offset = LPC18XX_RGU_ACTIVE_STATUS0;
+
+	offset += (id / LPC18XX_RGU_RESETS_PER_REG) * sizeof(u32);
+	bit = 1 << (id % LPC18XX_RGU_RESETS_PER_REG);
+
+	return !(readl(rc->base + offset) & bit);
+}
+
+static struct reset_control_ops lpc18xx_rgu_ops = {
+	.reset		= lpc18xx_rgu_reset,
+	.assert		= lpc18xx_rgu_assert,
+	.deassert	= lpc18xx_rgu_deassert,
+	.status		= lpc18xx_rgu_status,
+};
+
+static int lpc18xx_rgu_probe(struct platform_device *pdev)
+{
+	struct lpc18xx_rgu_data *rc;
+	struct resource *res;
+	u32 fcclk, firc;
+	int ret;
+
+	rc = devm_kzalloc(&pdev->dev, sizeof(*rc), GFP_KERNEL);
+	if (!rc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rc->base))
+		return PTR_ERR(rc->base);
+
+	rc->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	if (IS_ERR(rc->clk_reg)) {
+		dev_err(&pdev->dev, "reg clock not found\n");
+		return PTR_ERR(rc->clk_reg);
+	}
+
+	rc->clk_delay = devm_clk_get(&pdev->dev, "delay");
+	if (IS_ERR(rc->clk_delay)) {
+		dev_err(&pdev->dev, "delay clock not found\n");
+		return PTR_ERR(rc->clk_delay);
+	}
+
+	ret = clk_prepare_enable(rc->clk_reg);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable reg clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(rc->clk_delay);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable delay clock\n");
+		goto dis_clk_reg;
+	}
+
+	fcclk = clk_get_rate(rc->clk_reg) / USEC_PER_SEC;
+	firc = clk_get_rate(rc->clk_delay) / USEC_PER_SEC;
+	if (fcclk == 0 || firc == 0)
+		rc->delay_us = 2;
+	else
+		rc->delay_us = DIV_ROUND_UP(fcclk, firc * firc);
+
+	spin_lock_init(&rc->lock);
+
+	rc->rcdev.owner = THIS_MODULE;
+	rc->rcdev.nr_resets = 64;
+	rc->rcdev.ops = &lpc18xx_rgu_ops;
+	rc->rcdev.of_node = pdev->dev.of_node;
+
+	platform_set_drvdata(pdev, rc);
+
+	ret = reset_controller_register(&rc->rcdev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register device\n");
+		goto dis_clks;
+	}
+
+	rgu_base = rc->base;
+	ret = register_restart_handler(&lpc18xx_rgu_restart_nb);
+	if (ret)
+		dev_warn(&pdev->dev, "failed to register restart handler\n");
+
+	return 0;
+
+dis_clks:
+	clk_disable_unprepare(rc->clk_delay);
+dis_clk_reg:
+	clk_disable_unprepare(rc->clk_reg);
+
+	return ret;
+}
+
+static int lpc18xx_rgu_remove(struct platform_device *pdev)
+{
+	struct lpc18xx_rgu_data *rc = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = unregister_restart_handler(&lpc18xx_rgu_restart_nb);
+	if (ret)
+		dev_warn(&pdev->dev, "failed to unregister restart handler\n");
+
+	reset_controller_unregister(&rc->rcdev);
+
+	clk_disable_unprepare(rc->clk_delay);
+	clk_disable_unprepare(rc->clk_reg);
+
+	return 0;
+}
+
+static const struct of_device_id lpc18xx_rgu_match[] = {
+	{ .compatible = "nxp,lpc1850-rgu" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lpc18xx_rgu_match);
+
+static struct platform_driver lpc18xx_rgu_driver = {
+	.probe	= lpc18xx_rgu_probe,
+	.remove	= lpc18xx_rgu_remove,
+	.driver	= {
+		.name		= "lpc18xx-reset",
+		.of_match_table	= lpc18xx_rgu_match,
+	},
+};
+module_platform_driver(lpc18xx_rgu_driver);
+
+MODULE_AUTHOR("Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>");
+MODULE_DESCRIPTION("Reset driver for LPC18xx/43xx RGU");
+MODULE_LICENSE("GPL v2");
-- 
1.8.0

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[PATCH v3 2/2] doc: dt: add documentation for lpc1850-rgu reset driver

[Joachim Eastwood]

Add device tree binding documentation for the Reset Generation Unit
(RGU) found on NXP LPC18xx and LPC43xx devies.

This documentation also includes a table which shows the RGU reset
number and the connected peripheral.

Signed-off-by: Joachim Eastwood <manabian-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 .../devicetree/bindings/reset/nxp,lpc1850-rgu.txt  | 84 ++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/nxp,lpc1850-rgu.txt

diff --git a/Documentation/devicetree/bindings/reset/nxp,lpc1850-rgu.txt b/Documentation/devicetree/bindings/reset/nxp,lpc1850-rgu.txt
new file mode 100644
index 000000000000..b4e96a278445
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/nxp,lpc1850-rgu.txt
@@ -0,0 +1,84 @@
+NXP LPC1850  Reset Generation Unit (RGU)
+========================================
+
+Please also refer to reset.txt in this directory for common reset
+controller binding usage.
+
+Required properties:
+- compatible: Should be "nxp,lpc1850-rgu"
+- reg: register base and length
+- clocks: phandle and clock specifier to RGU clocks
+- clock-names: should contain "delay" and "reg"
+- #reset-cells: should be 1
+
+See table below for valid peripheral reset numbers. Numbers not
+in the table below are either reserved or not applicable for
+normal operation.
+
+Reset	Peripheral
+  9	System control unit (SCU)
+ 12	ARM Cortex-M0 subsystem core (LPC43xx only)
+ 13	CPU core
+ 16	LCD controller
+ 17	USB0
+ 18	USB1
+ 19	DMA
+ 20	SDIO
+ 21	External memory controller (EMC)
+ 22	Ethernet
+ 25	Flash bank A
+ 27	EEPROM
+ 28	GPIO
+ 29	Flash bank B
+ 32	Timer0
+ 33	Timer1
+ 34	Timer2
+ 35	Timer3
+ 36	Repetitive Interrupt timer (RIT)
+ 37	State Configurable Timer (SCT)
+ 38	Motor control PWM (MCPWM)
+ 39	QEI
+ 40	ADC0
+ 41	ADC1
+ 42	DAC
+ 44	USART0
+ 45	UART1
+ 46	USART2
+ 47	USART3
+ 48	I2C0
+ 49	I2C1
+ 50	SSP0
+ 51	SSP1
+ 52	I2S0 and I2S1
+ 53	Serial Flash Interface (SPIFI)
+ 54	C_CAN1
+ 55	C_CAN0
+ 56	ARM Cortex-M0 application core (LPC4370 only)
+ 57	SGPIO (LPC43xx only)
+ 58	SPI (LPC43xx only)
+ 60	ADCHS (12-bit ADC) (LPC4370 only)
+
+Refer to NXP LPC18xx or LPC43xx user manual for more details about
+the reset signals and the connected block/peripheral.
+
+Reset provider example:
+rgu: reset-controller@40053000 {
+	compatible = "nxp,lpc1850-rgu";
+	reg = <0x40053000 0x1000>;
+	clocks = <&cgu BASE_SAFE_CLK>, <&ccu1 CLK_CPU_BUS>;
+	clock-names = "delay", "reg";
+	#reset-cells = <1>;
+};
+
+Reset consumer example:
+mac: ethernet@40010000 {
+	compatible = "nxp,lpc1850-dwmac", "snps,dwmac-3.611", "snps,dwmac";
+	reg = <0x40010000 0x2000>;
+	interrupts = <5>;
+	interrupt-names = "macirq";
+	clocks = <&ccu1 CLK_CPU_ETHERNET>;
+	clock-names = "stmmaceth";
+	resets = <&rgu 22>;
+	reset-names = "stmmaceth";
+	status = "disabled";
+};
-- 
1.8.0

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Re: [PATCH v3 0/2] reset driver for NXP LPC18xx family

[Philipp Zabel]

Am Mittwoch, den 06.05.2015, 00:10 +0200 schrieb Joachim Eastwood:
> This patch set adds a reset driver for NXP LPC18xx/43xx devices.
> 
> Changes in v3:
> * add patch descriptions
> * change parameter name in to_rgu_data macro to avoid a potential
>   issue if code is changed.
> 
> Changes in v2:
> * clean up header includes
> * prefix M0 reset defines with LPC43XX
> * fix comment about M0 reset lines
> * reorganize reset call chains
> * add reset number table to dt doc
> 
> There are no dependencies in this patch set. The DTS changes will
> be sent separately to arm-soc once this patch set goes upstream.
> 
> Base support for the NXP LPC18xx family can be found here:
> http://marc.info/?l=linux-arm-kernel&m=143016894704253&w=2
> 
> Joachim Eastwood (2):
>   reset: add driver for lpc18xx rgu
>   doc: dt: add documentation for lpc1850-rgu reset driver

Applied both, thanks.

regards
Philipp

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Re: [PATCH v3 0/2] reset driver for NXP LPC18xx family

[Ezequiel Garcia]

On 05/07/2015 10:01 AM, Philipp Zabel wrote:
> Am Mittwoch, den 06.05.2015, 00:10 +0200 schrieb Joachim Eastwood:
>> This patch set adds a reset driver for NXP LPC18xx/43xx devices.
>>
>> Changes in v3:
>> * add patch descriptions
>> * change parameter name in to_rgu_data macro to avoid a potential
>>   issue if code is changed.
>>
>> Changes in v2:
>> * clean up header includes
>> * prefix M0 reset defines with LPC43XX
>> * fix comment about M0 reset lines
>> * reorganize reset call chains
>> * add reset number table to dt doc
>>
>> There are no dependencies in this patch set. The DTS changes will
>> be sent separately to arm-soc once this patch set goes upstream.
>>
>> Base support for the NXP LPC18xx family can be found here:
>> http://marc.info/?l=linux-arm-kernel&m=143016894704253&w=2
>>
>> Joachim Eastwood (2):
>>   reset: add driver for lpc18xx rgu
>>   doc: dt: add documentation for lpc1850-rgu reset driver
> 
> Applied both, thanks.
> 

Philipp,

Any chance we can have the reset controllers' tree to linux-next?

Thanks!
-- 
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar
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