| Message ID | 20180925094230.32679-4-m.felsch@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add GPIO brownout detection support | expand |
Hi Marco, On Tue, Sep 25, 2018 at 11:42:30AM +0200, Marco Felsch wrote: > A brownout can be detected in several ways e.g. a deticated pin on the > soc, a external pmic or by another external hardware which informs the > host via a gpio line. > > This patch adds the support for a generic gpio-based brownout > detection. Upon a brownout the host system gets informed and the driver > sends a keycode signal to the userspace. Per default this signal is > mapped to KEY_POWER, so the system will shoutdown. I do not believe this functionality should be exposed as an input device, as it has nothing to do with human interaction with the computing device. To me this is akin over-current on a USB port, or carrier signal on network interfaces. Why don't you simply send uevent for this platform device when you detect brownout, and have whatever entity is responsible for power management policy on your system listen to such events? Thanks. > > Additional the driver supports releasing registered devices from their > drivers, see Documentation/devicetree/bindings/input/gpio-brownout.txt > for more details. > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> > --- > .../bindings/input/gpio-brownout.txt | 36 ++++ > drivers/input/misc/Kconfig | 12 ++ > drivers/input/misc/Makefile | 1 + > drivers/input/misc/gpio-brownout.c | 166 ++++++++++++++++++ > 4 files changed, 215 insertions(+) > create mode 100644 Documentation/devicetree/bindings/input/gpio-brownout.txt > create mode 100644 drivers/input/misc/gpio-brownout.c > > diff --git a/Documentation/devicetree/bindings/input/gpio-brownout.txt b/Documentation/devicetree/bindings/input/gpio-brownout.txt > new file mode 100644 > index 000000000000..55fbe2aa52a9 > --- /dev/null > +++ b/Documentation/devicetree/bindings/input/gpio-brownout.txt > @@ -0,0 +1,36 @@ > +Device-Tree bindings for input/gpio_brownout.c driver > + > +Required properties: > +- compatible: Must be "gpio-brownout" > +- interrupt-parent: The phandle to the interrupt controller. For more details > + see ../interrupt-controller/interrupts.txt. > +- interrupts: The interrupt line for a brownout detection. For more details > + see ../interrupt-controller/interrupts.txt. > + > +Optional properties: > +- linux,code: Keycode to emit upon a brownout detection, default: KEY_POWER. > +- release-devices: A list of i2c or spi device phandles. All listed devices > + will be released from their drivers in the order they listed upon a brownout > + detection. This can be helpful to avoid a interrupt flood, because some > + system designs power off all external devices immediately and keep the host > + on for a certain time. > + > +Example: > + > +i2c3 { > + temp_core: lm75@48 { }; > + temp_chassis: lm75@49 { }; > +}; > + > +spi1 { > + ts: ad7879@1 { }; > +}; > + > +/ { > + gpio_brownout_det { > + compatible = "gpio-brownout"; > + interrupts-parent = <&gpio3>; > + interrupts = <3 IRQ_TYPE_EDGE_LOW>: > + release-devices = <&temp_core &ts>; > + }; > +}; > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig > index ca59a2be9bc5..6b49e681cca7 100644 > --- a/drivers/input/misc/Kconfig > +++ b/drivers/input/misc/Kconfig > @@ -268,6 +268,18 @@ config INPUT_GPIO_BEEPER > To compile this driver as a module, choose M here: the > module will be called gpio-beeper. > > +config INPUT_GPIO_BROWNOUT > + tristate "Generic GPIO Brownout detection support" > + depends on GPIOLIB || COMPILE_TEST > + help > + Say Y here if you have a brownout signal connected to a GPIO pin > + and want to report a keycode signal on a brownout detection. > + > + If unsure, say N. > + > + To compile this driver as a module, choose M here: the > + module will be called gpio-brownout. > + > config INPUT_GPIO_DECODER > tristate "Polled GPIO Decoder Input driver" > depends on GPIOLIB || COMPILE_TEST > diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile > index 9d0f9d1ff68f..8b872b5fc84a 100644 > --- a/drivers/input/misc/Makefile > +++ b/drivers/input/misc/Makefile > @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_DRV2665_HAPTICS) += drv2665.o > obj-$(CONFIG_INPUT_DRV2667_HAPTICS) += drv2667.o > obj-$(CONFIG_INPUT_GP2A) += gp2ap002a00f.o > obj-$(CONFIG_INPUT_GPIO_BEEPER) += gpio-beeper.o > +obj-$(CONFIG_INPUT_GPIO_BROWNOUT) += gpio-brownout.o > obj-$(CONFIG_INPUT_GPIO_DECODER) += gpio_decoder.o > obj-$(CONFIG_INPUT_HISI_POWERKEY) += hisi_powerkey.o > obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o > diff --git a/drivers/input/misc/gpio-brownout.c b/drivers/input/misc/gpio-brownout.c > new file mode 100644 > index 000000000000..23992b9e2814 > --- /dev/null > +++ b/drivers/input/misc/gpio-brownout.c > @@ -0,0 +1,166 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * gpio-brownout.c - Generic power fail driver > + * > + * Copyright (C) 2018 Pengutronix, Marco Felsch <kernel@pengutronix.de> > + */ > + > +#include <linux/gpio/consumer.h> > +#include <linux/i2c.h> > +#include <linux/input.h> > +#include <linux/interrupt.h> > +#include <linux/irqreturn.h> > +#include <linux/kernel.h> > +#include <linux/list.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/spi/spi.h> > + > +#define GPIO_BROWNOUT_MOD_NAME "gpio-brownout" > + > +struct gpio_brownout_device { > + struct list_head list; > + struct device *dev; > +}; > + > +struct gpio_brownout { > + struct device *dev; > + struct input_dev *idev; > + unsigned short kcode; > + struct list_head devices; > +}; > + > +static irqreturn_t gpio_brownout_isr(int irq, void *dev_id) > +{ > + struct gpio_brownout *gb = dev_id; > + struct input_dev *idev = gb->idev; > + struct gpio_brownout_device *bout_dev, *tmp; > + > + /* first inform userspace */ > + input_report_key(idev, gb->kcode, 1); > + input_sync(idev); > + > + /* now unregister registered drivers */ > + list_for_each_entry_safe(bout_dev, tmp, &gb->devices, list) { > + device_release_driver(bout_dev->dev); > + list_del(&bout_dev->list); > + } > + > + return IRQ_HANDLED; > +} > + > +#ifdef CONFIG_OF > +static int gpio_brownout_probe_dt(struct gpio_brownout *gb) > +{ > + struct device_node *np = gb->dev->of_node; > + struct of_phandle_iterator it; > + unsigned int kcode; > + int ret; > + > + /* all dt-properties are optional */ > + of_property_read_u32(np, "linux,code", &kcode); > + gb->kcode = kcode; > + > + /* > + * Register all devices which should be unbinded upon a brownout > + * detection. At the moment only i2c and spi devices are supported > + */ > + of_for_each_phandle(&it, ret, np, "release-devices", NULL, 0) { > + struct gpio_brownout_device *elem; > + struct i2c_client *i2c_c; > + struct spi_device *spi_c; > + > + i2c_c = of_find_i2c_device_by_node(it.node); > + spi_c = of_find_spi_device_by_node(it.node); > + > + if (!i2c_c && !spi_c) > + return -EPROBE_DEFER; > + else if (i2c_c && spi_c) > + return -EINVAL; > + > + elem = devm_kzalloc(gb->dev, sizeof(*elem), GFP_KERNEL); > + if (!elem) > + return -ENOMEM; > + > + elem->dev = i2c_c ? &i2c_c->dev : &spi_c->dev; > + > + INIT_LIST_HEAD(&elem->list); > + list_add_tail(&elem->list, &gb->devices); > + } > + > + return 0; > +} > +#endif > + > +static int gpio_brownout_probe(struct platform_device *pdev) > +{ > + struct gpio_brownout *gb; > + struct input_dev *idev; > + int ret, irq; > + > + gb = devm_kzalloc(&pdev->dev, sizeof(*gb), GFP_KERNEL); > + if (!gb) > + return -ENOMEM; > + > + idev = devm_input_allocate_device(&pdev->dev); > + if (!idev) > + return -ENOMEM; > + > + gb->dev = &pdev->dev; > + gb->idev = idev; > + INIT_LIST_HEAD(&gb->devices); > + > + if (IS_ENABLED(CONFIG_OF)) { > + ret = gpio_brownout_probe_dt(gb); > + if (ret) { > + dev_err(&pdev->dev, "probe_dt failed: %d\n", ret); > + return ret; > + } > + } > + > + idev->name = pdev->name; > + gb->kcode = gb->kcode == KEY_RESERVED ? KEY_POWER : gb->kcode; > + > + input_set_capability(idev, EV_KEY, gb->kcode); > + > + irq = platform_get_irq(pdev, 0); > + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, > + gpio_brownout_isr, IRQF_ONESHOT, > + GPIO_BROWNOUT_MOD_NAME, gb); > + if (ret < 0) { > + dev_err(&pdev->dev, "IRQ request failed: %d\n", ret); > + return ret; > + } > + > + ret = input_register_device(idev); > + if (ret) { > + dev_err(&pdev->dev, "Input register failed: %d\n", ret); > + return ret; > + } > + > + return 0; > +} > + > +#ifdef CONFIG_OF > +static const struct of_device_id gpio_brownout_of_match[] = { > + { .compatible = GPIO_BROWNOUT_MOD_NAME, }, > + { }, > +}; > +MODULE_DEVICE_TABLE(of, arm_gpio_brownout_of_match); > +#endif > + > +static struct platform_driver gpio_brownout_driver = { > + .driver = { > + .name = GPIO_BROWNOUT_MOD_NAME, > + .of_match_table = of_match_ptr(gpio_brownout_of_match) > + }, > + .probe = gpio_brownout_probe, > +}; > + > +module_platform_driver(gpio_brownout_driver); > + > +MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>"); > +MODULE_DESCRIPTION("GPIO Brownout Detection"); > +MODULE_LICENSE("GPL v2"); > -- > 2.19.0 >
Hi Dmitry, On 18-09-28 17:19, Dmitry Torokhov wrote: > Hi Marco, > > On Tue, Sep 25, 2018 at 11:42:30AM +0200, Marco Felsch wrote: > > A brownout can be detected in several ways e.g. a deticated pin on the > > soc, a external pmic or by another external hardware which informs the > > host via a gpio line. > > > > This patch adds the support for a generic gpio-based brownout > > detection. Upon a brownout the host system gets informed and the driver > > sends a keycode signal to the userspace. Per default this signal is > > mapped to KEY_POWER, so the system will shoutdown. > > I do not believe this functionality should be exposed as an input > device, as it has nothing to do with human interaction with the > computing device. To me this is akin over-current on a USB port, or > carrier signal on network interfaces. I'm still uncertain putting the code into the input framework. I tought a lot about the correct place. For me it's like a button, which is 'pressed' by the hardware. Yes, it's a bit abstract.. > Why don't you simply send uevent for this platform device when you > detect brownout, and have whatever entity is responsible for power > management policy on your system listen to such events? Since it is a special trigger (something went wrong with the supply), the system should shutdown. Many systems are using systemd (embedded ones too) which has a solid built-in mechanism to handle KEY_POWER events. This avoids rewriting services. I got your doubts. Can you give me your feedback? Maybe change rename it to a specific platform instead of the 'generic'. Thanks, Marco > Thanks. > > > > > Additional the driver supports releasing registered devices from their > > drivers, see Documentation/devicetree/bindings/input/gpio-brownout.txt > > for more details. > > > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> > > --- > > .../bindings/input/gpio-brownout.txt | 36 ++++ > > drivers/input/misc/Kconfig | 12 ++ > > drivers/input/misc/Makefile | 1 + > > drivers/input/misc/gpio-brownout.c | 166 ++++++++++++++++++ > > 4 files changed, 215 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/input/gpio-brownout.txt > > create mode 100644 drivers/input/misc/gpio-brownout.c > > > > diff --git a/Documentation/devicetree/bindings/input/gpio-brownout.txt b/Documentation/devicetree/bindings/input/gpio-brownout.txt > > new file mode 100644 > > index 000000000000..55fbe2aa52a9 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/input/gpio-brownout.txt > > @@ -0,0 +1,36 @@ > > +Device-Tree bindings for input/gpio_brownout.c driver > > + > > +Required properties: > > +- compatible: Must be "gpio-brownout" > > +- interrupt-parent: The phandle to the interrupt controller. For more details > > + see ../interrupt-controller/interrupts.txt. > > +- interrupts: The interrupt line for a brownout detection. For more details > > + see ../interrupt-controller/interrupts.txt. > > + > > +Optional properties: > > +- linux,code: Keycode to emit upon a brownout detection, default: KEY_POWER. > > +- release-devices: A list of i2c or spi device phandles. All listed devices > > + will be released from their drivers in the order they listed upon a brownout > > + detection. This can be helpful to avoid a interrupt flood, because some > > + system designs power off all external devices immediately and keep the host > > + on for a certain time. > > + > > +Example: > > + > > +i2c3 { > > + temp_core: lm75@48 { }; > > + temp_chassis: lm75@49 { }; > > +}; > > + > > +spi1 { > > + ts: ad7879@1 { }; > > +}; > > + > > +/ { > > + gpio_brownout_det { > > + compatible = "gpio-brownout"; > > + interrupts-parent = <&gpio3>; > > + interrupts = <3 IRQ_TYPE_EDGE_LOW>: > > + release-devices = <&temp_core &ts>; > > + }; > > +}; > > diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig > > index ca59a2be9bc5..6b49e681cca7 100644 > > --- a/drivers/input/misc/Kconfig > > +++ b/drivers/input/misc/Kconfig > > @@ -268,6 +268,18 @@ config INPUT_GPIO_BEEPER > > To compile this driver as a module, choose M here: the > > module will be called gpio-beeper. > > > > +config INPUT_GPIO_BROWNOUT > > + tristate "Generic GPIO Brownout detection support" > > + depends on GPIOLIB || COMPILE_TEST > > + help > > + Say Y here if you have a brownout signal connected to a GPIO pin > > + and want to report a keycode signal on a brownout detection. > > + > > + If unsure, say N. > > + > > + To compile this driver as a module, choose M here: the > > + module will be called gpio-brownout. > > + > > config INPUT_GPIO_DECODER > > tristate "Polled GPIO Decoder Input driver" > > depends on GPIOLIB || COMPILE_TEST > > diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile > > index 9d0f9d1ff68f..8b872b5fc84a 100644 > > --- a/drivers/input/misc/Makefile > > +++ b/drivers/input/misc/Makefile > > @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_DRV2665_HAPTICS) += drv2665.o > > obj-$(CONFIG_INPUT_DRV2667_HAPTICS) += drv2667.o > > obj-$(CONFIG_INPUT_GP2A) += gp2ap002a00f.o > > obj-$(CONFIG_INPUT_GPIO_BEEPER) += gpio-beeper.o > > +obj-$(CONFIG_INPUT_GPIO_BROWNOUT) += gpio-brownout.o > > obj-$(CONFIG_INPUT_GPIO_DECODER) += gpio_decoder.o > > obj-$(CONFIG_INPUT_HISI_POWERKEY) += hisi_powerkey.o > > obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o > > diff --git a/drivers/input/misc/gpio-brownout.c b/drivers/input/misc/gpio-brownout.c > > new file mode 100644 > > index 000000000000..23992b9e2814 > > --- /dev/null > > +++ b/drivers/input/misc/gpio-brownout.c > > @@ -0,0 +1,166 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * gpio-brownout.c - Generic power fail driver > > + * > > + * Copyright (C) 2018 Pengutronix, Marco Felsch <kernel@pengutronix.de> > > + */ > > + > > +#include <linux/gpio/consumer.h> > > +#include <linux/i2c.h> > > +#include <linux/input.h> > > +#include <linux/interrupt.h> > > +#include <linux/irqreturn.h> > > +#include <linux/kernel.h> > > +#include <linux/list.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/of_device.h> > > +#include <linux/platform_device.h> > > +#include <linux/spi/spi.h> > > + > > +#define GPIO_BROWNOUT_MOD_NAME "gpio-brownout" > > + > > +struct gpio_brownout_device { > > + struct list_head list; > > + struct device *dev; > > +}; > > + > > +struct gpio_brownout { > > + struct device *dev; > > + struct input_dev *idev; > > + unsigned short kcode; > > + struct list_head devices; > > +}; > > + > > +static irqreturn_t gpio_brownout_isr(int irq, void *dev_id) > > +{ > > + struct gpio_brownout *gb = dev_id; > > + struct input_dev *idev = gb->idev; > > + struct gpio_brownout_device *bout_dev, *tmp; > > + > > + /* first inform userspace */ > > + input_report_key(idev, gb->kcode, 1); > > + input_sync(idev); > > + > > + /* now unregister registered drivers */ > > + list_for_each_entry_safe(bout_dev, tmp, &gb->devices, list) { > > + device_release_driver(bout_dev->dev); > > + list_del(&bout_dev->list); > > + } > > + > > + return IRQ_HANDLED; > > +} > > + > > +#ifdef CONFIG_OF > > +static int gpio_brownout_probe_dt(struct gpio_brownout *gb) > > +{ > > + struct device_node *np = gb->dev->of_node; > > + struct of_phandle_iterator it; > > + unsigned int kcode; > > + int ret; > > + > > + /* all dt-properties are optional */ > > + of_property_read_u32(np, "linux,code", &kcode); > > + gb->kcode = kcode; > > + > > + /* > > + * Register all devices which should be unbinded upon a brownout > > + * detection. At the moment only i2c and spi devices are supported > > + */ > > + of_for_each_phandle(&it, ret, np, "release-devices", NULL, 0) { > > + struct gpio_brownout_device *elem; > > + struct i2c_client *i2c_c; > > + struct spi_device *spi_c; > > + > > + i2c_c = of_find_i2c_device_by_node(it.node); > > + spi_c = of_find_spi_device_by_node(it.node); > > + > > + if (!i2c_c && !spi_c) > > + return -EPROBE_DEFER; > > + else if (i2c_c && spi_c) > > + return -EINVAL; > > + > > + elem = devm_kzalloc(gb->dev, sizeof(*elem), GFP_KERNEL); > > + if (!elem) > > + return -ENOMEM; > > + > > + elem->dev = i2c_c ? &i2c_c->dev : &spi_c->dev; > > + > > + INIT_LIST_HEAD(&elem->list); > > + list_add_tail(&elem->list, &gb->devices); > > + } > > + > > + return 0; > > +} > > +#endif > > + > > +static int gpio_brownout_probe(struct platform_device *pdev) > > +{ > > + struct gpio_brownout *gb; > > + struct input_dev *idev; > > + int ret, irq; > > + > > + gb = devm_kzalloc(&pdev->dev, sizeof(*gb), GFP_KERNEL); > > + if (!gb) > > + return -ENOMEM; > > + > > + idev = devm_input_allocate_device(&pdev->dev); > > + if (!idev) > > + return -ENOMEM; > > + > > + gb->dev = &pdev->dev; > > + gb->idev = idev; > > + INIT_LIST_HEAD(&gb->devices); > > + > > + if (IS_ENABLED(CONFIG_OF)) { > > + ret = gpio_brownout_probe_dt(gb); > > + if (ret) { > > + dev_err(&pdev->dev, "probe_dt failed: %d\n", ret); > > + return ret; > > + } > > + } > > + > > + idev->name = pdev->name; > > + gb->kcode = gb->kcode == KEY_RESERVED ? KEY_POWER : gb->kcode; > > + > > + input_set_capability(idev, EV_KEY, gb->kcode); > > + > > + irq = platform_get_irq(pdev, 0); > > + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, > > + gpio_brownout_isr, IRQF_ONESHOT, > > + GPIO_BROWNOUT_MOD_NAME, gb); > > + if (ret < 0) { > > + dev_err(&pdev->dev, "IRQ request failed: %d\n", ret); > > + return ret; > > + } > > + > > + ret = input_register_device(idev); > > + if (ret) { > > + dev_err(&pdev->dev, "Input register failed: %d\n", ret); > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +#ifdef CONFIG_OF > > +static const struct of_device_id gpio_brownout_of_match[] = { > > + { .compatible = GPIO_BROWNOUT_MOD_NAME, }, > > + { }, > > +}; > > +MODULE_DEVICE_TABLE(of, arm_gpio_brownout_of_match); > > +#endif > > + > > +static struct platform_driver gpio_brownout_driver = { > > + .driver = { > > + .name = GPIO_BROWNOUT_MOD_NAME, > > + .of_match_table = of_match_ptr(gpio_brownout_of_match) > > + }, > > + .probe = gpio_brownout_probe, > > +}; > > + > > +module_platform_driver(gpio_brownout_driver); > > + > > +MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>"); > > +MODULE_DESCRIPTION("GPIO Brownout Detection"); > > +MODULE_LICENSE("GPL v2"); > > -- > > 2.19.0 > > > > -- > Dmitry >
On Mon, 2018-10-01 at 09:19 +0200, Marco Felsch wrote: > On 18-09-28 17:19, Dmitry Torokhov wrote: > > > > > > > > This patch adds the support for a generic gpio-based brownout > > > detection. Upon a brownout the host system gets informed and the driver > > > sends a keycode signal to the userspace. Per default this signal is > > > mapped to KEY_POWER, so the system will shoutdown. > > > > I do not believe this functionality should be exposed as an input > > device, as it has nothing to do with human interaction with the > > computing device. To me this is akin over-current on a USB port, or > > carrier signal on network interfaces. > > I'm still uncertain putting the code into the input framework. I tought > a lot about the correct place. For me it's like a button, which is > 'pressed' by the hardware. Yes, it's a bit abstract.. For quite a few years, the hwmon subsystem has had devices that will generate an interrupt on low voltage (or high voltage, or high temperature ...) and drivers that export that interrupt to userspace. This device doesn't seem any different that a somewhat limited hwmon device with just an "in0_alarm" attribute.
Hi Trent, On 18-10-01 16:35, Trent Piepho wrote: > On Mon, 2018-10-01 at 09:19 +0200, Marco Felsch wrote: > > On 18-09-28 17:19, Dmitry Torokhov wrote: > > > > > > > > > > > This patch adds the support for a generic gpio-based brownout > > > > detection. Upon a brownout the host system gets informed and the driver > > > > sends a keycode signal to the userspace. Per default this signal is > > > > mapped to KEY_POWER, so the system will shoutdown. > > > > > > I do not believe this functionality should be exposed as an input > > > device, as it has nothing to do with human interaction with the > > > computing device. To me this is akin over-current on a USB port, or > > > carrier signal on network interfaces. > > > > I'm still uncertain putting the code into the input framework. I tought > > a lot about the correct place. For me it's like a button, which is > > 'pressed' by the hardware. Yes, it's a bit abstract.. > > For quite a few years, the hwmon subsystem has had devices that will > generate an interrupt on low voltage (or high voltage, or high > temperature ...) and drivers that export that interrupt to userspace. > > This device doesn't seem any different that a somewhat limited hwmon > device with just an "in0_alarm" attribute. Thanks for the feedback and the idea. I will migrate the driver to the hwmon subsystem. Regards, Marco
diff --git a/Documentation/devicetree/bindings/input/gpio-brownout.txt b/Documentation/devicetree/bindings/input/gpio-brownout.txt new file mode 100644 index 000000000000..55fbe2aa52a9 --- /dev/null +++ b/Documentation/devicetree/bindings/input/gpio-brownout.txt @@ -0,0 +1,36 @@ +Device-Tree bindings for input/gpio_brownout.c driver + +Required properties: +- compatible: Must be "gpio-brownout" +- interrupt-parent: The phandle to the interrupt controller. For more details + see ../interrupt-controller/interrupts.txt. +- interrupts: The interrupt line for a brownout detection. For more details + see ../interrupt-controller/interrupts.txt. + +Optional properties: +- linux,code: Keycode to emit upon a brownout detection, default: KEY_POWER. +- release-devices: A list of i2c or spi device phandles. All listed devices + will be released from their drivers in the order they listed upon a brownout + detection. This can be helpful to avoid a interrupt flood, because some + system designs power off all external devices immediately and keep the host + on for a certain time. + +Example: + +i2c3 { + temp_core: lm75@48 { }; + temp_chassis: lm75@49 { }; +}; + +spi1 { + ts: ad7879@1 { }; +}; + +/ { + gpio_brownout_det { + compatible = "gpio-brownout"; + interrupts-parent = <&gpio3>; + interrupts = <3 IRQ_TYPE_EDGE_LOW>: + release-devices = <&temp_core &ts>; + }; +}; diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig index ca59a2be9bc5..6b49e681cca7 100644 --- a/drivers/input/misc/Kconfig +++ b/drivers/input/misc/Kconfig @@ -268,6 +268,18 @@ config INPUT_GPIO_BEEPER To compile this driver as a module, choose M here: the module will be called gpio-beeper. +config INPUT_GPIO_BROWNOUT + tristate "Generic GPIO Brownout detection support" + depends on GPIOLIB || COMPILE_TEST + help + Say Y here if you have a brownout signal connected to a GPIO pin + and want to report a keycode signal on a brownout detection. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called gpio-brownout. + config INPUT_GPIO_DECODER tristate "Polled GPIO Decoder Input driver" depends on GPIOLIB || COMPILE_TEST diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile index 9d0f9d1ff68f..8b872b5fc84a 100644 --- a/drivers/input/misc/Makefile +++ b/drivers/input/misc/Makefile @@ -35,6 +35,7 @@ obj-$(CONFIG_INPUT_DRV2665_HAPTICS) += drv2665.o obj-$(CONFIG_INPUT_DRV2667_HAPTICS) += drv2667.o obj-$(CONFIG_INPUT_GP2A) += gp2ap002a00f.o obj-$(CONFIG_INPUT_GPIO_BEEPER) += gpio-beeper.o +obj-$(CONFIG_INPUT_GPIO_BROWNOUT) += gpio-brownout.o obj-$(CONFIG_INPUT_GPIO_DECODER) += gpio_decoder.o obj-$(CONFIG_INPUT_HISI_POWERKEY) += hisi_powerkey.o obj-$(CONFIG_HP_SDC_RTC) += hp_sdc_rtc.o diff --git a/drivers/input/misc/gpio-brownout.c b/drivers/input/misc/gpio-brownout.c new file mode 100644 index 000000000000..23992b9e2814 --- /dev/null +++ b/drivers/input/misc/gpio-brownout.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * gpio-brownout.c - Generic power fail driver + * + * Copyright (C) 2018 Pengutronix, Marco Felsch <kernel@pengutronix.de> + */ + +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/input.h> +#include <linux/interrupt.h> +#include <linux/irqreturn.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> + +#define GPIO_BROWNOUT_MOD_NAME "gpio-brownout" + +struct gpio_brownout_device { + struct list_head list; + struct device *dev; +}; + +struct gpio_brownout { + struct device *dev; + struct input_dev *idev; + unsigned short kcode; + struct list_head devices; +}; + +static irqreturn_t gpio_brownout_isr(int irq, void *dev_id) +{ + struct gpio_brownout *gb = dev_id; + struct input_dev *idev = gb->idev; + struct gpio_brownout_device *bout_dev, *tmp; + + /* first inform userspace */ + input_report_key(idev, gb->kcode, 1); + input_sync(idev); + + /* now unregister registered drivers */ + list_for_each_entry_safe(bout_dev, tmp, &gb->devices, list) { + device_release_driver(bout_dev->dev); + list_del(&bout_dev->list); + } + + return IRQ_HANDLED; +} + +#ifdef CONFIG_OF +static int gpio_brownout_probe_dt(struct gpio_brownout *gb) +{ + struct device_node *np = gb->dev->of_node; + struct of_phandle_iterator it; + unsigned int kcode; + int ret; + + /* all dt-properties are optional */ + of_property_read_u32(np, "linux,code", &kcode); + gb->kcode = kcode; + + /* + * Register all devices which should be unbinded upon a brownout + * detection. At the moment only i2c and spi devices are supported + */ + of_for_each_phandle(&it, ret, np, "release-devices", NULL, 0) { + struct gpio_brownout_device *elem; + struct i2c_client *i2c_c; + struct spi_device *spi_c; + + i2c_c = of_find_i2c_device_by_node(it.node); + spi_c = of_find_spi_device_by_node(it.node); + + if (!i2c_c && !spi_c) + return -EPROBE_DEFER; + else if (i2c_c && spi_c) + return -EINVAL; + + elem = devm_kzalloc(gb->dev, sizeof(*elem), GFP_KERNEL); + if (!elem) + return -ENOMEM; + + elem->dev = i2c_c ? &i2c_c->dev : &spi_c->dev; + + INIT_LIST_HEAD(&elem->list); + list_add_tail(&elem->list, &gb->devices); + } + + return 0; +} +#endif + +static int gpio_brownout_probe(struct platform_device *pdev) +{ + struct gpio_brownout *gb; + struct input_dev *idev; + int ret, irq; + + gb = devm_kzalloc(&pdev->dev, sizeof(*gb), GFP_KERNEL); + if (!gb) + return -ENOMEM; + + idev = devm_input_allocate_device(&pdev->dev); + if (!idev) + return -ENOMEM; + + gb->dev = &pdev->dev; + gb->idev = idev; + INIT_LIST_HEAD(&gb->devices); + + if (IS_ENABLED(CONFIG_OF)) { + ret = gpio_brownout_probe_dt(gb); + if (ret) { + dev_err(&pdev->dev, "probe_dt failed: %d\n", ret); + return ret; + } + } + + idev->name = pdev->name; + gb->kcode = gb->kcode == KEY_RESERVED ? KEY_POWER : gb->kcode; + + input_set_capability(idev, EV_KEY, gb->kcode); + + irq = platform_get_irq(pdev, 0); + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, + gpio_brownout_isr, IRQF_ONESHOT, + GPIO_BROWNOUT_MOD_NAME, gb); + if (ret < 0) { + dev_err(&pdev->dev, "IRQ request failed: %d\n", ret); + return ret; + } + + ret = input_register_device(idev); + if (ret) { + dev_err(&pdev->dev, "Input register failed: %d\n", ret); + return ret; + } + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id gpio_brownout_of_match[] = { + { .compatible = GPIO_BROWNOUT_MOD_NAME, }, + { }, +}; +MODULE_DEVICE_TABLE(of, arm_gpio_brownout_of_match); +#endif + +static struct platform_driver gpio_brownout_driver = { + .driver = { + .name = GPIO_BROWNOUT_MOD_NAME, + .of_match_table = of_match_ptr(gpio_brownout_of_match) + }, + .probe = gpio_brownout_probe, +}; + +module_platform_driver(gpio_brownout_driver); + +MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>"); +MODULE_DESCRIPTION("GPIO Brownout Detection"); +MODULE_LICENSE("GPL v2");
A brownout can be detected in several ways e.g. a deticated pin on the soc, a external pmic or by another external hardware which informs the host via a gpio line. This patch adds the support for a generic gpio-based brownout detection. Upon a brownout the host system gets informed and the driver sends a keycode signal to the userspace. Per default this signal is mapped to KEY_POWER, so the system will shoutdown. Additional the driver supports releasing registered devices from their drivers, see Documentation/devicetree/bindings/input/gpio-brownout.txt for more details. Signed-off-by: Marco Felsch <m.felsch@pengutronix.de> --- .../bindings/input/gpio-brownout.txt | 36 ++++ drivers/input/misc/Kconfig | 12 ++ drivers/input/misc/Makefile | 1 + drivers/input/misc/gpio-brownout.c | 166 ++++++++++++++++++ 4 files changed, 215 insertions(+) create mode 100644 Documentation/devicetree/bindings/input/gpio-brownout.txt create mode 100644 drivers/input/misc/gpio-brownout.c