Commit 5611fe48 authored by Benjamin Collins's avatar Benjamin Collins Committed by Benjamin Herrenschmidt
Browse files

powerpc: Add support for CTS-1000 GPIO controlled system poweroff 



CTS-1000 is based on P4080. GPIO 27 is used to signal the FPGA to
switch off power, and also associates IRQ 8 with front-panel button
press (which we use to call orderly_poweroff()).

The relevant device-tree looks like this:

	gpio0: gpio@130000 {
		compatible = "fsl,qoriq-gpio";
		reg = <0x130000 0x1000>;
		interrupts = <55 2 0 0>;
		#gpio-cells = <2>;
		gpio-controller;

		/* Allows powering off the system via GPIO signal. */
		gpio-halt@27 {
			compatible = "sgy,gpio-halt";
			gpios = <&gpio0 27 0>;
			interrupts = <8 1 0 0>;
		};
	};

Because the driver cannot match on sgy,gpio-halt (because the node is never
processed through of_platform), it matches on fsl,qoriq-gpio and then
checks child nodes for the matching sgy,gpio-halt. This also ensures that
the GPIO controller is detected prior to sgy_cts1000's probe callback,
since that node wont match via of_platform until the controller is
registered.

Also, because the GPIO handler for triggering system poweroff might sleep,
the IRQ uses a workqueue to call orderly_poweroff().

As a final note, this driver may be expanded for other features specific to
the CTS-1000.

Signed-off-by: default avatarBen Collins <ben.c@servergy.com>
Cc: Jack Smith <jack.s@servergy.com>
Cc: Vihar Rai <vihar.r@servergy.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 34f364fe

arch/powerpc/platforms/85xx/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -245,6 +245,14 @@ config P4080_DS 
	help

	  This option enables support for the P4080 DS board



config SGY_CTS1000

	tristate "Servergy CTS-1000 support"

	select GPIOLIB

	select OF_GPIO

	depends on P4080_DS

	help

	  Enable this to support functionality in Servergy's CTS-1000 systems.



endif # PPC32



config P5020_DS

arch/powerpc/platforms/85xx/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -30,3 +30,4 @@ obj-$(CONFIG_KSI8560) += ksi8560.o 
obj-$(CONFIG_XES_MPC85xx) += xes_mpc85xx.o

obj-$(CONFIG_GE_IMP3A)	  += ge_imp3a.o

obj-$(CONFIG_PPC_QEMU_E500) += qemu_e500.o

obj-$(CONFIG_SGY_CTS1000) += sgy_cts1000.o

arch/powerpc/platforms/85xx/sgy_cts1000.c

0 → 100644
+176 −0
Original line number Diff line number Diff line 
/*

 * Servergy CTS-1000 Setup

 *

 * Maintained by Ben Collins <ben.c@servergy.com>

 *

 * Copyright 2012 by Servergy, Inc.

 *

 * This program is free software; you can redistribute  it and/or modify it

 * under  the terms of  the GNU General  Public License as published by the

 * Free Software Foundation;  either version 2 of the  License, or (at your

 * option) any later version.

 */



#include <linux/platform_device.h>

#include <linux/device.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/of_gpio.h>

#include <linux/workqueue.h>

#include <linux/reboot.h>

#include <linux/interrupt.h>



#include <asm/machdep.h>



static struct device_node *halt_node;



static struct of_device_id child_match[] = {

	{

		.compatible = "sgy,gpio-halt",

	},

	{},

};



static void gpio_halt_wfn(struct work_struct *work)

{

	/* Likely wont return */

	orderly_poweroff(true);

}

static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);



static void gpio_halt_cb(void)

{

	enum of_gpio_flags flags;

	int trigger, gpio;



	if (!halt_node)

		return;



	gpio = of_get_gpio_flags(halt_node, 0, &flags);



	if (!gpio_is_valid(gpio))

		return;



	trigger = (flags == OF_GPIO_ACTIVE_LOW);



	printk(KERN_INFO "gpio-halt: triggering GPIO.\n");



	/* Probably wont return */

	gpio_set_value(gpio, trigger);

}



/* This IRQ means someone pressed the power button and it is waiting for us

 * to handle the shutdown/poweroff. */

static irqreturn_t gpio_halt_irq(int irq, void *__data)

{

	printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");

	schedule_work(&gpio_halt_wq);



        return IRQ_HANDLED;

};



static int __devinit gpio_halt_probe(struct platform_device *pdev)

{

	enum of_gpio_flags flags;

	struct device_node *node = pdev->dev.of_node;

	int gpio, err, irq;

	int trigger;



	if (!node)

		return -ENODEV;



	/* If there's no matching child, this isn't really an error */

	halt_node = of_find_matching_node(node, child_match);

	if (!halt_node)

		return 0;



	/* Technically we could just read the first one, but punish

	 * DT writers for invalid form. */

	if (of_gpio_count(halt_node) != 1)

		return -EINVAL;



	/* Get the gpio number relative to the dynamic base. */

	gpio = of_get_gpio_flags(halt_node, 0, &flags);

	if (!gpio_is_valid(gpio))

		return -EINVAL;



	err = gpio_request(gpio, "gpio-halt");

	if (err) {

		printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",

		       gpio);

		halt_node = NULL;

		return err;

	}



	trigger = (flags == OF_GPIO_ACTIVE_LOW);



	gpio_direction_output(gpio, !trigger);



	/* Now get the IRQ which tells us when the power button is hit */

	irq = irq_of_parse_and_map(halt_node, 0);

	err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |

			  IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);

	if (err) {

		printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "

		       "GPIO %d.\n", irq, gpio);

		gpio_free(gpio);

		halt_node = NULL;

		return err;

	}



	/* Register our halt function */

	ppc_md.halt = gpio_halt_cb;

	ppc_md.power_off = gpio_halt_cb;



	printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"

	       " irq).\n", gpio, trigger, irq);



	return 0;

}



static int __devexit gpio_halt_remove(struct platform_device *pdev)

{

	if (halt_node) {

		int gpio = of_get_gpio(halt_node, 0);

		int irq = irq_of_parse_and_map(halt_node, 0);



		free_irq(irq, halt_node);



		ppc_md.halt = NULL;

		ppc_md.power_off = NULL;



		gpio_free(gpio);



		halt_node = NULL;

	}



	return 0;

}



static struct of_device_id gpio_halt_match[] = {

	/* We match on the gpio bus itself and scan the children since they

	 * wont be matched against us. We know the bus wont match until it

	 * has been registered too. */

	{

		.compatible = "fsl,qoriq-gpio",

	},

	{},

};

MODULE_DEVICE_TABLE(of, gpio_halt_match);



static struct platform_driver gpio_halt_driver = {

	.driver = {

		.name		= "gpio-halt",

		.owner		= THIS_MODULE,

		.of_match_table = gpio_halt_match,

	},

	.probe		= gpio_halt_probe,

	.remove		= __devexit_p(gpio_halt_remove),

};



module_platform_driver(gpio_halt_driver);



MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");

MODULE_VERSION("1.0");

MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");

MODULE_LICENSE("GPL");

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