/* * GPIO controller in LSI ZEVIO SoCs. * * Author: Fabian Vogt <fabian@ritter-vogt.de> * * 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. */ #include <linux/spinlock.h> #include <linux/errno.h> #include <linux/module.h> #include <linux/bitops.h> #include <linux/io.h> #include <linux/of_device.h> #include <linux/of_gpio.h> #include <linux/slab.h> #include <linux/gpio.h> /* * Memory layout: * This chip has four gpio sections, each controls 8 GPIOs. * Bit 0 in section 0 is GPIO 0, bit 2 in section 1 is GPIO 10. * Disclaimer: Reverse engineered! * For more information refer to: * http://hackspire.unsads.com/wiki/index.php/Memory-mapped_I/O_ports#90000000_-_General_Purpose_I.2FO_.28GPIO.29 * * 0x00-0x3F: Section 0 * +0x00: Masked interrupt status (read-only) * +0x04: R: Interrupt status W: Reset interrupt status * +0x08: R: Interrupt mask W: Mask interrupt * +0x0C: W: Unmask interrupt (write-only) * +0x10: Direction: I/O=1/0 * +0x14: Output * +0x18: Input (read-only) * +0x20: R: Level interrupt W: Set as level interrupt * 0x40-0x7F: Section 1 * 0x80-0xBF: Section 2 * 0xC0-0xFF: Section 3 */ #define ZEVIO_GPIO_SECTION_SIZE 0x40 /* Offsets to various registers */ #define ZEVIO_GPIO_INT_MASKED_STATUS 0x00 #define ZEVIO_GPIO_INT_STATUS 0x04 #define ZEVIO_GPIO_INT_UNMASK 0x08 #define ZEVIO_GPIO_INT_MASK 0x0C #define ZEVIO_GPIO_DIRECTION 0x10 #define ZEVIO_GPIO_OUTPUT 0x14 #define ZEVIO_GPIO_INPUT 0x18 #define ZEVIO_GPIO_INT_STICKY 0x20 #define to_zevio_gpio(chip) container_of(to_of_mm_gpio_chip(chip), \ struct zevio_gpio, chip) /* Bit number of GPIO in its section */ #define ZEVIO_GPIO_BIT(gpio) (gpio&7) struct zevio_gpio { spinlock_t lock; struct of_mm_gpio_chip chip; }; static inline u32 zevio_gpio_port_get(struct zevio_gpio *c, unsigned pin, unsigned port_offset) { unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE; return readl(IOMEM(c->chip.regs + section_offset + port_offset)); } static inline void zevio_gpio_port_set(struct zevio_gpio *c, unsigned pin, unsigned port_offset, u32 val) { unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE; writel(val, IOMEM(c->chip.regs + section_offset + port_offset)); } /* Functions for struct gpio_chip */ static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin) { struct zevio_gpio *controller = to_zevio_gpio(chip); /* Only reading allowed, so no spinlock needed */ u32 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT); return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1; } static void zevio_gpio_set(struct gpio_chip *chip, unsigned pin, int value) { struct zevio_gpio *controller = to_zevio_gpio(chip); u32 val; spin_lock(&controller->lock); val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); if (value) val |= BIT(ZEVIO_GPIO_BIT(pin)); else val &= ~BIT(ZEVIO_GPIO_BIT(pin)); zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val); spin_unlock(&controller->lock); } static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin) { struct zevio_gpio *controller = to_zevio_gpio(chip); u32 val; spin_lock(&controller->lock); val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); val |= BIT(ZEVIO_GPIO_BIT(pin)); zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val); spin_unlock(&controller->lock); return 0; } static int zevio_gpio_direction_output(struct gpio_chip *chip, unsigned pin, int value) { struct zevio_gpio *controller = to_zevio_gpio(chip); u32 val; spin_lock(&controller->lock); val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); if (value) val |= BIT(ZEVIO_GPIO_BIT(pin)); else val &= ~BIT(ZEVIO_GPIO_BIT(pin)); zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val); val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); val &= ~BIT(ZEVIO_GPIO_BIT(pin)); zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val); spin_unlock(&controller->lock); return 0; } static int zevio_gpio_to_irq(struct gpio_chip *chip, unsigned pin) { /* * TODO: Implement IRQs. * Not implemented yet due to weird lockups */ return -ENXIO; } static struct gpio_chip zevio_gpio_chip = { .direction_input = zevio_gpio_direction_input, .direction_output = zevio_gpio_direction_output, .set = zevio_gpio_set, .get = zevio_gpio_get, .to_irq = zevio_gpio_to_irq, .base = 0, .owner = THIS_MODULE, .ngpio = 32, .of_gpio_n_cells = 2, }; /* Initialization */ static int zevio_gpio_probe(struct platform_device *pdev) { struct zevio_gpio *controller; int status, i; controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL); if (!controller) { dev_err(&pdev->dev, "not enough free memory\n"); return -ENOMEM; } /* Copy our reference */ controller->chip.gc = zevio_gpio_chip; controller->chip.gc.dev = &pdev->dev; status = of_mm_gpiochip_add(pdev->dev.of_node, &(controller->chip)); if (status) { dev_err(&pdev->dev, "failed to add gpiochip: %d\n", status); return status; } spin_lock_init(&controller->lock); /* Disable interrupts, they only cause errors */ for (i = 0; i < controller->chip.gc.ngpio; i += 8) zevio_gpio_port_set(controller, i, ZEVIO_GPIO_INT_MASK, 0xFF); dev_dbg(controller->chip.gc.dev, "ZEVIO GPIO controller set up!\n"); return 0; } static struct of_device_id zevio_gpio_of_match[] = { { .compatible = "lsi,zevio-gpio", }, { }, }; MODULE_DEVICE_TABLE(of, zevio_gpio_of_match); static struct platform_driver zevio_gpio_driver = { .driver = { .name = "gpio-zevio", .owner = THIS_MODULE, .of_match_table = of_match_ptr(zevio_gpio_of_match), }, .probe = zevio_gpio_probe, }; module_platform_driver(zevio_gpio_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Fabian Vogt <fabian@ritter-vogt.de>"); MODULE_DESCRIPTION("LSI ZEVIO SoC GPIO driver");