/drivers/gpio/gpio-sch.c
http://github.com/mirrors/linux · C · 224 lines · 156 code · 43 blank · 25 comment · 8 complexity · 483d1db04c4bd65128bcf6e56b12fe32 MD5 · raw file
- // SPDX-License-Identifier: GPL-2.0
- /*
- * GPIO interface for Intel Poulsbo SCH
- *
- * Copyright (c) 2010 CompuLab Ltd
- * Author: Denis Turischev <denis@compulab.co.il>
- */
- #include <linux/acpi.h>
- #include <linux/errno.h>
- #include <linux/gpio/driver.h>
- #include <linux/io.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/pci_ids.h>
- #include <linux/platform_device.h>
- #define GEN 0x00
- #define GIO 0x04
- #define GLV 0x08
- struct sch_gpio {
- struct gpio_chip chip;
- spinlock_t lock;
- unsigned short iobase;
- unsigned short resume_base;
- };
- static unsigned sch_gpio_offset(struct sch_gpio *sch, unsigned gpio,
- unsigned reg)
- {
- unsigned base = 0;
- if (gpio >= sch->resume_base) {
- gpio -= sch->resume_base;
- base += 0x20;
- }
- return base + reg + gpio / 8;
- }
- static unsigned sch_gpio_bit(struct sch_gpio *sch, unsigned gpio)
- {
- if (gpio >= sch->resume_base)
- gpio -= sch->resume_base;
- return gpio % 8;
- }
- static int sch_gpio_reg_get(struct sch_gpio *sch, unsigned gpio, unsigned reg)
- {
- unsigned short offset, bit;
- u8 reg_val;
- offset = sch_gpio_offset(sch, gpio, reg);
- bit = sch_gpio_bit(sch, gpio);
- reg_val = !!(inb(sch->iobase + offset) & BIT(bit));
- return reg_val;
- }
- static void sch_gpio_reg_set(struct sch_gpio *sch, unsigned gpio, unsigned reg,
- int val)
- {
- unsigned short offset, bit;
- u8 reg_val;
- offset = sch_gpio_offset(sch, gpio, reg);
- bit = sch_gpio_bit(sch, gpio);
- reg_val = inb(sch->iobase + offset);
- if (val)
- outb(reg_val | BIT(bit), sch->iobase + offset);
- else
- outb((reg_val & ~BIT(bit)), sch->iobase + offset);
- }
- static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
- {
- struct sch_gpio *sch = gpiochip_get_data(gc);
- spin_lock(&sch->lock);
- sch_gpio_reg_set(sch, gpio_num, GIO, 1);
- spin_unlock(&sch->lock);
- return 0;
- }
- static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
- {
- struct sch_gpio *sch = gpiochip_get_data(gc);
- return sch_gpio_reg_get(sch, gpio_num, GLV);
- }
- static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
- {
- struct sch_gpio *sch = gpiochip_get_data(gc);
- spin_lock(&sch->lock);
- sch_gpio_reg_set(sch, gpio_num, GLV, val);
- spin_unlock(&sch->lock);
- }
- static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
- int val)
- {
- struct sch_gpio *sch = gpiochip_get_data(gc);
- spin_lock(&sch->lock);
- sch_gpio_reg_set(sch, gpio_num, GIO, 0);
- spin_unlock(&sch->lock);
- /*
- * according to the datasheet, writing to the level register has no
- * effect when GPIO is programmed as input.
- * Actually the the level register is read-only when configured as input.
- * Thus presetting the output level before switching to output is _NOT_ possible.
- * Hence we set the level after configuring the GPIO as output.
- * But we cannot prevent a short low pulse if direction is set to high
- * and an external pull-up is connected.
- */
- sch_gpio_set(gc, gpio_num, val);
- return 0;
- }
- static int sch_gpio_get_direction(struct gpio_chip *gc, unsigned gpio_num)
- {
- struct sch_gpio *sch = gpiochip_get_data(gc);
- if (sch_gpio_reg_get(sch, gpio_num, GIO))
- return GPIO_LINE_DIRECTION_IN;
- return GPIO_LINE_DIRECTION_OUT;
- }
- static const struct gpio_chip sch_gpio_chip = {
- .label = "sch_gpio",
- .owner = THIS_MODULE,
- .direction_input = sch_gpio_direction_in,
- .get = sch_gpio_get,
- .direction_output = sch_gpio_direction_out,
- .set = sch_gpio_set,
- .get_direction = sch_gpio_get_direction,
- };
- static int sch_gpio_probe(struct platform_device *pdev)
- {
- struct sch_gpio *sch;
- struct resource *res;
- sch = devm_kzalloc(&pdev->dev, sizeof(*sch), GFP_KERNEL);
- if (!sch)
- return -ENOMEM;
- res = platform_get_resource(pdev, IORESOURCE_IO, 0);
- if (!res)
- return -EBUSY;
- if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
- pdev->name))
- return -EBUSY;
- spin_lock_init(&sch->lock);
- sch->iobase = res->start;
- sch->chip = sch_gpio_chip;
- sch->chip.label = dev_name(&pdev->dev);
- sch->chip.parent = &pdev->dev;
- switch (pdev->id) {
- case PCI_DEVICE_ID_INTEL_SCH_LPC:
- sch->resume_base = 10;
- sch->chip.ngpio = 14;
- /*
- * GPIO[6:0] enabled by default
- * GPIO7 is configured by the CMC as SLPIOVR
- * Enable GPIO[9:8] core powered gpios explicitly
- */
- sch_gpio_reg_set(sch, 8, GEN, 1);
- sch_gpio_reg_set(sch, 9, GEN, 1);
- /*
- * SUS_GPIO[2:0] enabled by default
- * Enable SUS_GPIO3 resume powered gpio explicitly
- */
- sch_gpio_reg_set(sch, 13, GEN, 1);
- break;
- case PCI_DEVICE_ID_INTEL_ITC_LPC:
- sch->resume_base = 5;
- sch->chip.ngpio = 14;
- break;
- case PCI_DEVICE_ID_INTEL_CENTERTON_ILB:
- sch->resume_base = 21;
- sch->chip.ngpio = 30;
- break;
- case PCI_DEVICE_ID_INTEL_QUARK_X1000_ILB:
- sch->resume_base = 2;
- sch->chip.ngpio = 8;
- break;
- default:
- return -ENODEV;
- }
- platform_set_drvdata(pdev, sch);
- return devm_gpiochip_add_data(&pdev->dev, &sch->chip, sch);
- }
- static struct platform_driver sch_gpio_driver = {
- .driver = {
- .name = "sch_gpio",
- },
- .probe = sch_gpio_probe,
- };
- module_platform_driver(sch_gpio_driver);
- MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
- MODULE_DESCRIPTION("GPIO interface for Intel Poulsbo SCH");
- MODULE_LICENSE("GPL v2");
- MODULE_ALIAS("platform:sch_gpio");