253 lines
6.5 KiB
C
253 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Intel INT0002 "Virtual GPIO" driver
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*
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* Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
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*
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* Loosely based on android x86 kernel code which is:
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*
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* Copyright (c) 2014, Intel Corporation.
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*
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* Author: Dyut Kumar Sil <dyut.k.sil@intel.com>
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*
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* Some peripherals on Bay Trail and Cherry Trail platforms signal a Power
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* Management Event (PME) to the Power Management Controller (PMC) to wakeup
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* the system. When this happens software needs to clear the PME bus 0 status
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* bit in the GPE0a_STS register to avoid an IRQ storm on IRQ 9.
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*
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* This is modelled in ACPI through the INT0002 ACPI device, which is
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* called a "Virtual GPIO controller" in ACPI because it defines the event
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* handler to call when the PME triggers through _AEI and _L02 / _E02
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* methods as would be done for a real GPIO interrupt in ACPI. Note this
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* is a hack to define an AML event handler for the PME while using existing
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* ACPI mechanisms, this is not a real GPIO at all.
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*
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* This driver will bind to the INT0002 device, and register as a GPIO
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* controller, letting gpiolib-acpi.c call the _L02 handler as it would
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* for a real GPIO controller.
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*/
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#include <linux/acpi.h>
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#include <linux/bitmap.h>
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#include <linux/gpio/driver.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/suspend.h>
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#include <asm/cpu_device_id.h>
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#include <asm/intel-family.h>
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#define DRV_NAME "INT0002 Virtual GPIO"
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/* For some reason the virtual GPIO pin tied to the GPE is numbered pin 2 */
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#define GPE0A_PME_B0_VIRT_GPIO_PIN 2
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#define GPE0A_PME_B0_STS_BIT BIT(13)
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#define GPE0A_PME_B0_EN_BIT BIT(13)
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#define GPE0A_STS_PORT 0x420
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#define GPE0A_EN_PORT 0x428
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/*
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* As this is not a real GPIO at all, but just a hack to model an event in
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* ACPI the get / set functions are dummy functions.
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*/
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static int int0002_gpio_get(struct gpio_chip *chip, unsigned int offset)
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{
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return 0;
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}
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static void int0002_gpio_set(struct gpio_chip *chip, unsigned int offset,
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int value)
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{
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}
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static int int0002_gpio_direction_output(struct gpio_chip *chip,
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unsigned int offset, int value)
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{
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return 0;
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}
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static void int0002_irq_ack(struct irq_data *data)
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{
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outl(GPE0A_PME_B0_STS_BIT, GPE0A_STS_PORT);
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}
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static void int0002_irq_unmask(struct irq_data *data)
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{
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u32 gpe_en_reg;
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gpe_en_reg = inl(GPE0A_EN_PORT);
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gpe_en_reg |= GPE0A_PME_B0_EN_BIT;
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outl(gpe_en_reg, GPE0A_EN_PORT);
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}
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static void int0002_irq_mask(struct irq_data *data)
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{
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u32 gpe_en_reg;
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gpe_en_reg = inl(GPE0A_EN_PORT);
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gpe_en_reg &= ~GPE0A_PME_B0_EN_BIT;
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outl(gpe_en_reg, GPE0A_EN_PORT);
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}
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static int int0002_irq_set_wake(struct irq_data *data, unsigned int on)
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{
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struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
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struct platform_device *pdev = to_platform_device(chip->parent);
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int irq = platform_get_irq(pdev, 0);
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/* Propagate to parent irq */
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if (on)
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enable_irq_wake(irq);
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else
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disable_irq_wake(irq);
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return 0;
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}
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static irqreturn_t int0002_irq(int irq, void *data)
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{
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struct gpio_chip *chip = data;
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u32 gpe_sts_reg;
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gpe_sts_reg = inl(GPE0A_STS_PORT);
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if (!(gpe_sts_reg & GPE0A_PME_B0_STS_BIT))
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return IRQ_NONE;
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generic_handle_irq(irq_find_mapping(chip->irq.domain,
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GPE0A_PME_B0_VIRT_GPIO_PIN));
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pm_wakeup_hard_event(chip->parent);
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return IRQ_HANDLED;
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}
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static struct irq_chip int0002_byt_irqchip = {
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.name = DRV_NAME,
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.irq_ack = int0002_irq_ack,
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.irq_mask = int0002_irq_mask,
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.irq_unmask = int0002_irq_unmask,
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.irq_set_wake = int0002_irq_set_wake,
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};
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static struct irq_chip int0002_cht_irqchip = {
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.name = DRV_NAME,
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.irq_ack = int0002_irq_ack,
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.irq_mask = int0002_irq_mask,
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.irq_unmask = int0002_irq_unmask,
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/*
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* No set_wake, on CHT the IRQ is typically shared with the ACPI SCI
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* and we don't want to mess with the ACPI SCI irq settings.
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*/
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.flags = IRQCHIP_SKIP_SET_WAKE,
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};
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static const struct x86_cpu_id int0002_cpu_ids[] = {
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INTEL_CPU_FAM6(ATOM_SILVERMONT, int0002_byt_irqchip), /* Valleyview, Bay Trail */
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INTEL_CPU_FAM6(ATOM_AIRMONT, int0002_cht_irqchip), /* Braswell, Cherry Trail */
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{}
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};
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static void int0002_init_irq_valid_mask(struct gpio_chip *chip,
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unsigned long *valid_mask,
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unsigned int ngpios)
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{
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bitmap_clear(valid_mask, 0, GPE0A_PME_B0_VIRT_GPIO_PIN);
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}
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static int int0002_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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const struct x86_cpu_id *cpu_id;
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struct irq_chip *irq_chip;
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struct gpio_chip *chip;
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int irq, ret;
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/* Menlow has a different INT0002 device? <sigh> */
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cpu_id = x86_match_cpu(int0002_cpu_ids);
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if (!cpu_id)
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return -ENODEV;
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return irq;
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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chip->label = DRV_NAME;
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chip->parent = dev;
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chip->owner = THIS_MODULE;
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chip->get = int0002_gpio_get;
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chip->set = int0002_gpio_set;
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chip->direction_input = int0002_gpio_get;
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chip->direction_output = int0002_gpio_direction_output;
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chip->base = -1;
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chip->ngpio = GPE0A_PME_B0_VIRT_GPIO_PIN + 1;
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chip->irq.init_valid_mask = int0002_init_irq_valid_mask;
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ret = devm_gpiochip_add_data(&pdev->dev, chip, NULL);
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if (ret) {
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dev_err(dev, "Error adding gpio chip: %d\n", ret);
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return ret;
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}
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/*
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* We manually request the irq here instead of passing a flow-handler
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* to gpiochip_set_chained_irqchip, because the irq is shared.
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*/
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ret = devm_request_irq(dev, irq, int0002_irq,
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IRQF_SHARED, "INT0002", chip);
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if (ret) {
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dev_err(dev, "Error requesting IRQ %d: %d\n", irq, ret);
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return ret;
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}
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irq_chip = (struct irq_chip *)cpu_id->driver_data;
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ret = gpiochip_irqchip_add(chip, irq_chip, 0, handle_edge_irq,
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IRQ_TYPE_NONE);
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if (ret) {
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dev_err(dev, "Error adding irqchip: %d\n", ret);
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return ret;
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}
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gpiochip_set_chained_irqchip(chip, irq_chip, irq, NULL);
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device_init_wakeup(dev, true);
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return 0;
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}
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static int int0002_remove(struct platform_device *pdev)
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{
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device_init_wakeup(&pdev->dev, false);
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return 0;
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}
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static const struct acpi_device_id int0002_acpi_ids[] = {
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{ "INT0002", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(acpi, int0002_acpi_ids);
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static struct platform_driver int0002_driver = {
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.driver = {
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.name = DRV_NAME,
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.acpi_match_table = int0002_acpi_ids,
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},
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.probe = int0002_probe,
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.remove = int0002_remove,
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};
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module_platform_driver(int0002_driver);
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MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
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MODULE_DESCRIPTION("Intel INT0002 Virtual GPIO driver");
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MODULE_LICENSE("GPL v2");
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