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Release 4.7 drivers/gpio/gpio-zevio.c

Directory: drivers/gpio
/*
 * 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/init.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

/* 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)); }

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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)); }

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/* Functions for struct gpio_chip */
static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin) { struct zevio_gpio *controller = gpiochip_get_data(chip); u32 val, dir; spin_lock(&controller->lock); dir = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); if (dir & BIT(ZEVIO_GPIO_BIT(pin))) val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT); else val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); spin_unlock(&controller->lock); return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1; }

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static void zevio_gpio_set(struct gpio_chip *chip, unsigned pin, int value) { struct zevio_gpio *controller = gpiochip_get_data(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); }

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static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin) { struct zevio_gpio *controller = gpiochip_get_data(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; }

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static int zevio_gpio_direction_output(struct gpio_chip *chip, unsigned pin, int value) { struct zevio_gpio *controller = gpiochip_get_data(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; }

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static int zevio_gpio_to_irq(struct gpio_chip *chip, unsigned pin) { /* * TODO: Implement IRQs. * Not implemented yet due to weird lockups */ return -ENXIO; }

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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) return -ENOMEM; platform_set_drvdata(pdev, controller); /* Copy our reference */ controller->chip.gc = zevio_gpio_chip; controller->chip.gc.parent = &pdev->dev; status = of_mm_gpiochip_add_data(pdev->dev.of_node, &(controller->chip), controller); 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.parent, "ZEVIO GPIO controller set up!\n"); return 0; }

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static const struct of_device_id zevio_gpio_of_match[] = { { .compatible = "lsi,zevio-gpio", }, { }, }; static struct platform_driver zevio_gpio_driver = { .driver = { .name = "gpio-zevio", .of_match_table = zevio_gpio_of_match, .suppress_bind_attrs = true, }, .probe = zevio_gpio_probe, }; builtin_platform_driver(zevio_gpio_driver);

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Directory: drivers/gpio
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