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kernel/linux-imx6_3.14.28/drivers/gpio/gpio-octeon.c 3.77 KB
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  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Copyright (C) 2011, 2012 Cavium Inc.
   */
  
  #include <linux/platform_device.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/gpio.h>
  #include <linux/io.h>
  
  #include <asm/octeon/octeon.h>
  #include <asm/octeon/cvmx-gpio-defs.h>
  
  #define RX_DAT 0x80
  #define TX_SET 0x88
  #define TX_CLEAR 0x90
  /*
   * The address offset of the GPIO configuration register for a given
   * line.
   */
  static unsigned int bit_cfg_reg(unsigned int offset)
  {
  	/*
  	 * The register stride is 8, with a discontinuity after the
  	 * first 16.
  	 */
  	if (offset < 16)
  		return 8 * offset;
  	else
  		return 8 * (offset - 16) + 0x100;
  }
  
  struct octeon_gpio {
  	struct gpio_chip chip;
  	u64 register_base;
  };
  
  static int octeon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
  {
  	struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  
  	cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0);
  	return 0;
  }
  
  static void octeon_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  {
  	struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  	u64 mask = 1ull << offset;
  	u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR);
  	cvmx_write_csr(reg, mask);
  }
  
  static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset,
  			       int value)
  {
  	struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  	union cvmx_gpio_bit_cfgx cfgx;
  
  	octeon_gpio_set(chip, offset, value);
  
  	cfgx.u64 = 0;
  	cfgx.s.tx_oe = 1;
  
  	cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64);
  	return 0;
  }
  
  static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset)
  {
  	struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  	u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT);
  
  	return ((1ull << offset) & read_bits) != 0;
  }
  
  static int octeon_gpio_probe(struct platform_device *pdev)
  {
  	struct octeon_gpio *gpio;
  	struct gpio_chip *chip;
  	struct resource *res_mem;
  	int err = 0;
  
  	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
  	if (!gpio)
  		return -ENOMEM;
  	chip = &gpio->chip;
  
  	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (res_mem == NULL) {
  		dev_err(&pdev->dev, "found no memory resource
  ");
  		err = -ENXIO;
  		goto out;
  	}
  	if (!devm_request_mem_region(&pdev->dev, res_mem->start,
  					resource_size(res_mem),
  				     res_mem->name)) {
  		dev_err(&pdev->dev, "request_mem_region failed
  ");
  		err = -ENXIO;
  		goto out;
  	}
  	gpio->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
  						resource_size(res_mem));
  
  	pdev->dev.platform_data = chip;
  	chip->label = "octeon-gpio";
  	chip->dev = &pdev->dev;
  	chip->owner = THIS_MODULE;
  	chip->base = 0;
  	chip->can_sleep = false;
  	chip->ngpio = 20;
  	chip->direction_input = octeon_gpio_dir_in;
  	chip->get = octeon_gpio_get;
  	chip->direction_output = octeon_gpio_dir_out;
  	chip->set = octeon_gpio_set;
  	err = gpiochip_add(chip);
  	if (err)
  		goto out;
  
  	dev_info(&pdev->dev, "OCTEON GPIO driver probed.
  ");
  out:
  	return err;
  }
  
  static int octeon_gpio_remove(struct platform_device *pdev)
  {
  	struct gpio_chip *chip = pdev->dev.platform_data;
  	return gpiochip_remove(chip);
  }
  
  static struct of_device_id octeon_gpio_match[] = {
  	{
  		.compatible = "cavium,octeon-3860-gpio",
  	},
  	{},
  };
  MODULE_DEVICE_TABLE(of, octeon_gpio_match);
  
  static struct platform_driver octeon_gpio_driver = {
  	.driver = {
  		.name		= "octeon_gpio",
  		.owner		= THIS_MODULE,
  		.of_match_table = octeon_gpio_match,
  	},
  	.probe		= octeon_gpio_probe,
  	.remove		= octeon_gpio_remove,
  };
  
  module_platform_driver(octeon_gpio_driver);
  
  MODULE_DESCRIPTION("Cavium Inc. OCTEON GPIO Driver");
  MODULE_AUTHOR("David Daney");
  MODULE_LICENSE("GPL");