Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757279AbaJIOww (ORCPT ); Thu, 9 Oct 2014 10:52:52 -0400 Received: from filter1.ibarracuda.nl ([83.247.7.10]:45143 "EHLO filter1.ibarracuda.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbaJIOwb (ORCPT ); Thu, 9 Oct 2014 10:52:31 -0400 X-ASG-Debug-ID: 1412866348-0759e74828314360002-xx1T2L X-Barracuda-Envelope-From: Frans.Klaver@xsens.com X-Barracuda-AUTH-User: xsenscom X-Barracuda-Apparent-Source-IP: 87.249.116.215 From: Frans Klaver To: Sebastian Reichel CC: =?UTF-8?q?Ren=C3=A9=20Moll?= , Tjerk Hofmeijer , Frans Klaver , Dmitry Eremin-Solenikov , David Woodhouse , Grant Likely , Rob Herring , Guenter Roeck , , , Subject: [PATCH v4 1/2] power: reset: add LTC2952 poweroff support Date: Thu, 9 Oct 2014 16:50:41 +0200 X-ASG-Orig-Subj: [PATCH v4 1/2] power: reset: add LTC2952 poweroff support Message-ID: <1412866242-6474-2-git-send-email-frans.klaver@xsens.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1412866242-6474-1-git-send-email-frans.klaver@xsens.com> References: <1412866242-6474-1-git-send-email-frans.klaver@xsens.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [172.16.11.125] X-Barracuda-Connect: rev-215.116.249.87.virtu.nl[87.249.116.215] X-Barracuda-Start-Time: 1412866348 X-Barracuda-Encrypted: AES128-SHA X-Barracuda-URL: http://filter1.ibarracuda.nl:8000/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=5.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.10375 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: René Moll The LTC2952 allows control over system power using a push button. It also supports powering down the board from a controller on the board. If the power button is pushed, the ltc2952 starts a 400ms window to properly shut down the software. This window can be stretched by toggling a watchdog line. This driver always uses this watchdog line. The power button input is optional. This allows the system to use a custom shutdown sequence on the push button. On software shutdown the driver sets the kill signal, starting the same sequence as if the push button was used. Signed-off-by: René Moll Signed-off-by: Tjerk Hofmeijer Signed-off-by: Frans Klaver --- drivers/power/reset/Kconfig | 10 + drivers/power/reset/Makefile | 1 + drivers/power/reset/ltc2952-poweroff.c | 327 +++++++++++++++++++++++++++++++++ 3 files changed, 338 insertions(+) create mode 100644 drivers/power/reset/ltc2952-poweroff.c diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index ca41523..a0f68da 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -45,6 +45,16 @@ config POWER_RESET_HISI help Reboot support for Hisilicon boards. +config POWER_RESET_LTC2952 + bool "LTC2952 PowerPath power-off driver" + depends on OF_GPIO && POWER_RESET + help + This driver supports an external powerdown trigger and board + power down via the LTC2952. + + If your board uses an LTC2952, say Y and create a binding + in the device tree. + config POWER_RESET_MSM bool "Qualcomm MSM power-off driver" depends on POWER_RESET && ARCH_QCOM diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index a42e70e..3cbb7c3 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -3,6 +3,7 @@ obj-$(CONFIG_POWER_RESET_AXXIA) += axxia-reset.o obj-$(CONFIG_POWER_RESET_BRCMSTB) += brcmstb-reboot.o obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o +obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o obj-$(CONFIG_POWER_RESET_QNAP) += qnap-poweroff.o obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o diff --git a/drivers/power/reset/ltc2952-poweroff.c b/drivers/power/reset/ltc2952-poweroff.c new file mode 100644 index 0000000..5c6e2a95 --- /dev/null +++ b/drivers/power/reset/ltc2952-poweroff.c @@ -0,0 +1,327 @@ +/* + * LTC2952 PowerPath TM driver + * + * Copyright (C) 2014, Xsens Technologies BV + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * ---------------------------------------- + * - Description + * ---------------------------------------- + * + * This driver is to be used with an external LTC2952 PowerPath Controller. + * Its function is to determine when a external shutdown is triggered and react + * by properly shutting down the system. + * + * This driver expects a device tree with a ltc2952 entry for pin mapping. + * + * ---------------------------------------- + * - GPIO + * ---------------------------------------- + * + * The following GPIOs are used: + * - trigger (input, optional) + * Input active indicates the shutdown trigger. If its state reverts to + * inactive within the timeout defined by trigger_delay, the system won't + * be shut down. If no pin is assigned to this input the driver will start + * the watchdog immediately and only a power off event will poweroff the + * ltc2952 + * + * - watchdog (output) + * Once a shutdown is triggered, the driver will toggle this signal, with + * an internal (wde_interval) to stall the hardware shut down. + * + * - poweroff (output) + * The last action during shutdown is triggering this signalling, such + * that the PowerPath Control will power down the hardware. + * + * ---------------------------------------- + * - Interrupts + * ---------------------------------------- + * + * The driver requires a non-shared, edge-triggered interrupt on the trigger + * GPIO. + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define WDE_TIMEOUT ktime_set(0, 300L*1E6L) +#define TRIGGER_TIMEOUT ktime_set(2, 500L*1E6L) + +struct ltc2952_poweroff { + struct hrtimer timer_trigger; + struct hrtimer timer_wde; + + ktime_t trigger_delay; + ktime_t wde_interval; + + struct device *dev; + + struct gpio_desc *gpio_trigger; + struct gpio_desc *gpio_watchdog; + struct gpio_desc *gpio_poweroff; + + bool kernel_panic; + struct notifier_block panic_notifier; +}; +#define to_ltc2952(p, m) container_of(p, struct ltc2952_poweroff, m) + +/** + * ltc2952_poweroff_timer_wde - Timer callback + * Toggles the watchdog reset signal each wde_interval + * + * @timer: corresponding timer + * + * Returns HRTIMER_RESTART for an infinite loop which will only stop when the + * machine actually shuts down + */ +static enum hrtimer_restart ltc2952_poweroff_timer_wde(struct hrtimer *timer) +{ + ktime_t now; + int state; + struct ltc2952_poweroff *data = to_ltc2952(timer, timer_wde); + + if (data->kernel_panic) + return HRTIMER_NORESTART; + + state = gpiod_get_value(data->gpio_watchdog); + gpiod_set_value(data->gpio_watchdog, !state); + + now = hrtimer_cb_get_time(timer); + hrtimer_forward(timer, now, data->wde_interval); + + return HRTIMER_RESTART; +} + +static void ltc2952_poweroff_start_wde(struct ltc2952_poweroff *data) +{ + if (hrtimer_start(&data->timer_wde, + data->wde_interval, HRTIMER_MODE_REL)) { + /* + * The device will not toggle the watchdog reset, + * thus shut down is only safe if the PowerPath controller + * has a long enough time-off before triggering a hardware + * power-off. + * + * Only mention the error, as the system will power-off anyway + */ + dev_err(data->dev, "unable to start the watchdog timer\n"); + } +} + +static enum hrtimer_restart ltc2952_poweroff_timer_trigger(struct hrtimer *t) +{ + struct ltc2952_poweroff *data = to_ltc2952(t, timer_trigger); + + dev_info(data->dev, "executing shutdown\n"); + ltc2952_poweroff_start_wde(data); + orderly_poweroff(true); + return HRTIMER_NORESTART; +} + +/** + * ltc2952_poweroff_handler - Interrupt handler + * + * Activate or deactive the shutdown timeout, based on the value of the trigger + * gpio. If the button is pressed for long enough, the shutdown timer fires and + * the system is actually shut down. + * + * @irq: IRQ number + * @dev_id: pointer to the main data structure + */ +static irqreturn_t ltc2952_poweroff_handler(int irq, void *dev_id) +{ + struct ltc2952_poweroff *data = dev_id; + + if (data->kernel_panic || hrtimer_active(&data->timer_wde)) + /* we're either panicking, or already shutting down */ + return IRQ_HANDLED; + + if (gpiod_get_value(data->gpio_trigger)) { + /* button pressed */ + if (hrtimer_start(&data->timer_trigger, data->trigger_delay, + HRTIMER_MODE_REL)) + dev_err(data->dev, "unable to start the wait timer\n"); + } else { + /* button released */ + hrtimer_cancel(&data->timer_trigger); + } + + return IRQ_HANDLED; +} + +static int ltc2952_poweroff_init(struct platform_device *pdev) +{ + struct ltc2952_poweroff *data = platform_get_drvdata(pdev); + + data->wde_interval = WDE_TIMEOUT; + data->trigger_delay = TRIGGER_TIMEOUT; + + hrtimer_init(&data->timer_trigger, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + data->timer_trigger.function = ltc2952_poweroff_timer_trigger; + + hrtimer_init(&data->timer_wde, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + data->timer_wde.function = ltc2952_poweroff_timer_wde; + + data->gpio_watchdog = devm_gpiod_get(&pdev->dev, "watchdog", + GPIOD_OUT_LOW); + if (IS_ERR(data->gpio_watchdog)) { + dev_err(&pdev->dev, "unable to claim watchdog-gpio\n"); + return PTR_ERR(data->gpio_watchdog); + } + + data->gpio_poweroff = devm_gpiod_get(&pdev->dev, "poweroff", + GPIOD_OUT_LOW); + if (IS_ERR(data->gpio_poweroff)) { + dev_err(&pdev->dev, "unable to claim poweroff-gpio\n"); + return PTR_ERR(data->gpio_poweroff); + } + + data->gpio_trigger = devm_gpiod_get(&pdev->dev, "trigger", GPIOD_IN); + if (IS_ERR(data->gpio_trigger)) { + /* + * It's not a problem if the trigger gpio isn't available, but + * it is worth a warning its use was defined in the device + * tree. + */ + if (PTR_ERR(data->gpio_trigger) != -ENOENT) + dev_warn(&pdev->dev, "unable to claim trigger-gpio\n"); + data->gpio_trigger = NULL; + } + + if (devm_request_irq(&pdev->dev, + gpiod_to_irq(data->gpio_trigger), + ltc2952_poweroff_handler, + (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING), + KBUILD_MODNAME, data)) { + /* + * No trigger input was defined, claiming the gpio failed, we + * couldn't map to an irq, or we couldn't register the + * interrupt handler. None of these should be a real problem, + * but all of them disqualify the push button from controlling + * the power. + * + * It is therefore important to note that if the ltc2952 detects + * a button press for long enough, it will still start its own + * powerdown window and cut the power on us if we don't start + * the watchdog trigger. + */ + if (data->gpio_trigger) { + dev_warn(&pdev->dev, + "unable to configure the trigger interrupt\n"); + devm_gpiod_put(&pdev->dev, data->gpio_trigger); + data->gpio_trigger = NULL; + } + + dev_info(&pdev->dev, "power down trigger input is not used\n"); + ltc2952_poweroff_start_wde(data); + } + + return 0; +} + +static int ltc2952_poweroff_notify_panic(struct notifier_block *nb, + unsigned long code, + void *unused) +{ + struct ltc2952_poweroff *data = to_ltc2952(nb, panic_notifier); + + data->kernel_panic = true; + return NOTIFY_DONE; +} + +/* We need a global pointer here */ +static struct ltc2952_poweroff *ltc2952_data; + +static void ltc2952_poweroff_poweroff(void) +{ + gpiod_set_value(ltc2952_data->gpio_poweroff, 1); +} + +static int ltc2952_poweroff_probe(struct platform_device *pdev) +{ + int ret; + struct ltc2952_poweroff *data; + + if (ltc2952_data) { + dev_err(&pdev->dev, "already probed"); + return -ENODEV; + } + + if (pm_power_off) { + dev_err(&pdev->dev, "pm_power_off already registered"); + return -EBUSY; + } + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->dev = &pdev->dev; + platform_set_drvdata(pdev, data); + + ret = ltc2952_poweroff_init(pdev); + if (ret) + return ret; + + pm_power_off = ltc2952_poweroff_poweroff; + ltc2952_data = data; + + data->panic_notifier.notifier_call = ltc2952_poweroff_notify_panic; + atomic_notifier_chain_register(&panic_notifier_list, + &data->panic_notifier); + dev_info(&pdev->dev, "probe successful\n"); + return 0; +} + +static int ltc2952_poweroff_remove(struct platform_device *pdev) +{ + struct ltc2952_poweroff *data = platform_get_drvdata(pdev); + + pm_power_off = NULL; + hrtimer_cancel(&data->timer_wde); + + atomic_notifier_chain_unregister(&panic_notifier_list, + &data->panic_notifier); + return 0; +} + +static const struct of_device_id of_ltc2952_poweroff_match[] = { + { .compatible = "lltc,ltc2952"}, + {}, +}; +MODULE_DEVICE_TABLE(of, of_ltc2952_poweroff_match); + +static struct platform_driver ltc2952_poweroff_driver = { + .probe = ltc2952_poweroff_probe, + .remove = ltc2952_poweroff_remove, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = of_ltc2952_poweroff_match, + }, +}; +module_platform_driver(ltc2952_poweroff_driver); + +MODULE_AUTHOR("René Moll "); +MODULE_AUTHOR("Frans Klaver "); +MODULE_AUTHOR("Tjerk Hofmeijer "); +MODULE_DESCRIPTION("LTC PowerPath power-off driver"); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/