Re: [PATCH v6] platform/x86: Add driver for ACPI INT0002 Virtual GPIO device

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Fri, Jun 2, 2017 at 6:15 PM, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> Some peripherals on Bay Trail and Cherry Trail platforms signal a
> Power Management Event (PME) to the Power Management Controller (PMC)
> to wakeup the system. When this happens software needs to explicitly
> clear the PME bus 0 status bit in the GPE0a_STS register to avoid an
> IRQ storm on IRQ 9.
>
> This is modelled in ACPI through the INT0002 ACPI device, which is
> called a "Virtual GPIO controller" in ACPI because it defines the
> event handler to call when the PME triggers through _AEI and _L02
> methods as would be done for a real GPIO interrupt in ACPI.
>
> This commit adds a driver which registers the Virtual GPIOs expected
> by the DSDT on these devices, letting gpiolib-acpi claim the
> virtual GPIO and install a GPIO-interrupt handler which call the _L02
> handler as it would for a real GPIO controller.
>

Pushed to testing w/o Linus' tag (there is no one yet)

Linus, if you have objections, tell me.

> Cc: joeyli <jlee@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxx>
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> Changes in v2:
> -Remove dev_err after malloc failure
> -Remove unused empty runtime pm callbacks
> -s/GPE0A_PME_/GPE0A_PME_B0_/
> -Fixed some checkpatch warnings (I forgot to run checkpatch on v1)
> Changes in v3:
> -Rewrite as gpiochip driver letting gpiolib-acpi deal with claiming the pin
>  0x0002 and calling the _L02 event handler when the virtual gpio-irq triggers
> -Rebase on 4.12-rc1
> Changes in v4:
> -Drop device_init_wakeup() from _probe(), use pm_system_wakeup() instead
>  of pm_wakeup_hard_event(chip->parent)
> -Improve commit message
> Changes in v5:
> -Use BIT() macro for FOO_BIT defines
> -Drop unneeded ACPI_PTR macro usage
> Changes in v6:
> -Move back to drivers/platform/x86
> -Expand certain acronyms (PME, PMC)
> -Use linux/gpio/driver.h include instead of linux/gpio.h
> -Document why the get / set / direction_output functions are dummys
> -No functional changes
> ---
>  drivers/platform/x86/Kconfig               |  19 +++
>  drivers/platform/x86/Makefile              |   1 +
>  drivers/platform/x86/intel_int0002_vgpio.c | 218 +++++++++++++++++++++++++++++
>  3 files changed, 238 insertions(+)
>  create mode 100644 drivers/platform/x86/intel_int0002_vgpio.c
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 8489020..a3ccc3c 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -794,6 +794,25 @@ config INTEL_CHT_INT33FE
>           This driver instantiates i2c-clients for these, so that standard
>           i2c drivers for these chips can bind to the them.
>
> +config INTEL_INT0002_VGPIO
> +       tristate "Intel ACPI INT0002 Virtual GPIO driver"
> +       depends on GPIOLIB && ACPI
> +       select GPIOLIB_IRQCHIP
> +       ---help---
> +         Some peripherals on Bay Trail and Cherry Trail platforms signal a
> +         Power Management Event (PME) to the Power Management Controller (PMC)
> +         to wakeup the system. When this happens software needs to explicitly
> +         clear the PME bus 0 status bit in the GPE0a_STS register to avoid an
> +         IRQ storm on IRQ 9.
> +
> +         This is modelled in ACPI through the INT0002 ACPI device, which is
> +         called a "Virtual GPIO controller" in ACPI because it defines the
> +         event handler to call when the PME triggers through _AEI and _L02
> +         methods as would be done for a real GPIO interrupt in ACPI.
> +
> +         To compile this driver as a module, choose M here: the module will
> +         be called intel_int0002_vgpio.
> +
>  config INTEL_HID_EVENT
>         tristate "INTEL HID Event"
>         depends on ACPI
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 182a3ed..ab22ce7 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -46,6 +46,7 @@ obj-$(CONFIG_TOSHIBA_BT_RFKILL)       += toshiba_bluetooth.o
>  obj-$(CONFIG_TOSHIBA_HAPS)     += toshiba_haps.o
>  obj-$(CONFIG_TOSHIBA_WMI)      += toshiba-wmi.o
>  obj-$(CONFIG_INTEL_CHT_INT33FE)        += intel_cht_int33fe.o
> +obj-$(CONFIG_INTEL_INT0002_VGPIO) += intel_int0002_vgpio.o
>  obj-$(CONFIG_INTEL_HID_EVENT)  += intel-hid.o
>  obj-$(CONFIG_INTEL_VBTN)       += intel-vbtn.o
>  obj-$(CONFIG_INTEL_SCU_IPC)    += intel_scu_ipc.o
> diff --git a/drivers/platform/x86/intel_int0002_vgpio.c b/drivers/platform/x86/intel_int0002_vgpio.c
> new file mode 100644
> index 0000000..e524b49
> --- /dev/null
> +++ b/drivers/platform/x86/intel_int0002_vgpio.c
> @@ -0,0 +1,218 @@
> +/*
> + * Intel INT0002 "Virtual GPIO" driver
> + *
> + * Copyright (C) 2017 Hans de Goede <hdegoede@xxxxxxxxxx>
> + *
> + * Loosely based on android x86 kernel code which is:
> + *
> + * Copyright (c) 2014, Intel Corporation.
> + *
> + * Author: Dyut Kumar Sil <dyut.k.sil@xxxxxxxxx>
> + *
> + * 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.
> + *
> + * Some peripherals on Bay Trail and Cherry Trail platforms signal a Power
> + * Management Event (PME) to the Power Management Controller (PMC) to wakeup
> + * the system. When this happens software needs to clear the PME bus 0 status
> + * bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
> + *
> + * This is modelled in ACPI through the INT0002 ACPI device, which is
> + * called a "Virtual GPIO controller" in ACPI because it defines the event
> + * handler to call when the PME triggers through _AEI and _L02 / _E02
> + * methods as would be done for a real GPIO interrupt in ACPI. Note this
> + * is a hack to define an AML event handler for the PME while using existing
> + * ACPI mechanisms, this is not a real GPIO at all.
> + *
> + * This driver will bind to the INT0002 device, and register as a GPIO
> + * controller, letting gpiolib-acpi.c call the _L02 handler as it would
> + * for a real GPIO controller.
> + */
> +
> +#include <asm/cpu_device_id.h>
> +#include <asm/intel-family.h>
> +#include <linux/acpi.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/suspend.h>
> +
> +#define DRV_NAME                       "INT0002 Virtual GPIO"
> +
> +/* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */
> +#define GPE0A_PME_B0_VIRT_GPIO_PIN     2
> +
> +#define GPE0A_PME_B0_STS_BIT           BIT(13)
> +#define GPE0A_PME_B0_EN_BIT            BIT(13)
> +#define GPE0A_STS_PORT                 0x420
> +#define GPE0A_EN_PORT                  0x428
> +
> +#define ICPU(model)    { X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
> +
> +static const struct x86_cpu_id int0002_cpu_ids[] = {
> +/*
> + * Limit ourselves to Cherry Trail for now, until testing shows we
> + * need to handle the INT0002 device on Baytrail too.
> + *     ICPU(INTEL_FAM6_ATOM_SILVERMONT1),       * Valleyview, Bay Trail *
> + */
> +       ICPU(INTEL_FAM6_ATOM_AIRMONT),          /* Braswell, Cherry Trail */
> +       {}
> +};
> +
> +/*
> + * As this is not a real GPIO at all, but just a hack to model an event in
> + * APCI the get / set functions are dummy functions.
> + */
> +
> +static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +       return 0;
> +}
> +
> +static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
> +                            int value)
> +{
> +}
> +
> +static int int0002_gpio_direction_output(struct gpio_chip *chip,
> +                                        unsigned int offset, int value)
> +{
> +       return 0;
> +}
> +
> +static void int0002_irq_ack(struct irq_data *data)
> +{
> +       outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
> +}
> +
> +static void int0002_irq_unmask(struct irq_data *data)
> +{
> +       u32 gpe_en_reg;
> +
> +       gpe_en_reg = inl(GPE0A_EN_PORT);
> +       gpe_en_reg |= GPE0A_PME_B0_EN_BIT;
> +       outl(gpe_en_reg, GPE0A_EN_PORT);
> +}
> +
> +static void int0002_irq_mask(struct irq_data *data)
> +{
> +       u32 gpe_en_reg;
> +
> +       gpe_en_reg = inl(GPE0A_EN_PORT);
> +       gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
> +       outl(gpe_en_reg, GPE0A_EN_PORT);
> +}
> +
> +static irqreturn_t int0002_irq(int irq, void *data)
> +{
> +       struct gpio_chip *chip = data;
> +       u32 gpe_sts_reg;
> +
> +       gpe_sts_reg = inl(GPE0A_STS_PORT);
> +       if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
> +               return IRQ_NONE;
> +
> +       generic_handle_irq(irq_find_mapping(chip->irqdomain,
> +                                           GPE0A_PME_B0_VIRT_GPIO_PIN));
> +
> +       pm_system_wakeup();
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static struct irq_chip int0002_irqchip = {
> +       .name                   = DRV_NAME,
> +       .irq_ack                = int0002_irq_ack,
> +       .irq_mask               = int0002_irq_mask,
> +       .irq_unmask             = int0002_irq_unmask,
> +};
> +
> +static int int0002_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       const struct x86_cpu_id *cpu_id;
> +       struct gpio_chip *chip;
> +       int i, irq, ret;
> +
> +       /* Menlow has a different INT0002 device? <sigh> */
> +       cpu_id = x86_match_cpu(int0002_cpu_ids);
> +       if (!cpu_id)
> +               return -ENODEV;
> +
> +       irq = platform_get_irq(pdev, 0);
> +       if (irq < 0) {
> +               dev_err(dev, "Error getting IRQ: %d\n", irq);
> +               return irq;
> +       }
> +
> +       chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
> +       if (!chip)
> +               return -ENOMEM;
> +
> +       chip->label = DRV_NAME;
> +       chip->parent = dev;
> +       chip->owner = THIS_MODULE;
> +       chip->get = int0002_gpio_get;
> +       chip->set = int0002_gpio_set;
> +       chip->direction_input = int0002_gpio_get;
> +       chip->direction_output = int0002_gpio_direction_output;
> +       chip->base = -1;
> +       chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
> +       chip->irq_need_valid_mask = true;
> +
> +       ret = devm_gpiochip_add_data(&pdev->dev, chip, NULL);
> +       if (ret) {
> +               dev_err(dev, "Error adding gpio chip: %d\n", ret);
> +               return ret;
> +       }
> +
> +       for (i = 0; i < GPE0A_PME_B0_VIRT_GPIO_PIN; i++)
> +               clear_bit(i, chip->irq_valid_mask);
> +
> +       /*
> +        * We manually request the irq here instead of passing a flow-handler
> +        * to gpiochip_set_chained_irqchip, because the irq is shared.
> +        */
> +       ret = devm_request_irq(dev, irq, int0002_irq,
> +                              IRQF_SHARED | IRQF_NO_THREAD, "INT0002", chip);
> +       if (ret) {
> +               dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
> +               return ret;
> +       }
> +
> +       ret = gpiochip_irqchip_add(chip, &int0002_irqchip, 0, handle_edge_irq,
> +                                  IRQ_TYPE_NONE);
> +       if (ret) {
> +               dev_err(dev, "Error adding irqchip: %d\n", ret);
> +               return ret;
> +       }
> +
> +       gpiochip_set_chained_irqchip(chip, &int0002_irqchip, irq, NULL);
> +
> +       return 0;
> +}
> +
> +static const struct acpi_device_id int0002_acpi_ids[] = {
> +       { "INT0002", 0 },
> +       { },
> +};
> +MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);
> +
> +static struct platform_driver int0002_driver = {
> +       .driver = {
> +               .name                   = DRV_NAME,
> +               .acpi_match_table       = int0002_acpi_ids,
> +       },
> +       .probe  = int0002_probe,
> +};
> +
> +module_platform_driver(int0002_driver);
> +
> +MODULE_AUTHOR("Hans de Goede <hdegoede@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
> +MODULE_LICENSE("GPL");
> --
> 2.9.4
>



-- 
With Best Regards,
Andy Shevchenko
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