drivers/gpio/gpio-octeon.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2011, 2012 Cavium Inc.
   7  */
   8
   9 #include <linux/platform_device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/gpio.h>
  13 #include <linux/io.h>
  14
  15 #include <asm/octeon/octeon.h>
  16 #include <asm/octeon/cvmx-gpio-defs.h>
  17
  18 #define RX_DAT 0x80
  19 #define TX_SET 0x88
  20 #define TX_CLEAR 0x90
  21 /*
  22  * The address offset of the GPIO configuration register for a given
  23  * line.
  24  */
  25 static unsigned int bit_cfg_reg(unsigned int offset)
  26 {
  27         /*
  28          * The register stride is 8, with a discontinuity after the
  29          * first 16.
  30          */
  31         if (offset < 16)
  32                 return 8 * offset;
  33         else
  34                 return 8 * (offset - 16) + 0x100;
  35 }
  36
  37 struct octeon_gpio {
  38         struct gpio_chip chip;
  39         u64 register_base;
  40 };
  41
  42 static int octeon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
  43 {
  44         struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  45
  46         cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0);
  47         return 0;
  48 }
  49
  50 static void octeon_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  51 {
  52         struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  53         u64 mask = 1ull << offset;
  54         u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR);
  55         cvmx_write_csr(reg, mask);
  56 }
  57
  58 static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset,
  59                                int value)
  60 {
  61         struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  62         union cvmx_gpio_bit_cfgx cfgx;
  63
  64         octeon_gpio_set(chip, offset, value);
  65
  66         cfgx.u64 = 0;
  67         cfgx.s.tx_oe = 1;
  68
  69         cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64);
  70         return 0;
  71 }
  72
  73 static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset)
  74 {
  75         struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
  76         u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT);
  77
  78         return ((1ull << offset) & read_bits) != 0;
  79 }
  80
  81 static int octeon_gpio_probe(struct platform_device *pdev)
  82 {
  83         struct octeon_gpio *gpio;
  84         struct gpio_chip *chip;
  85         struct resource *res_mem;
  86         int err = 0;
  87
  88         gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
  89         if (!gpio)
  90                 return -ENOMEM;
  91         chip = &gpio->chip;
  92
  93         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  94         if (res_mem == NULL) {
  95                 dev_err(&pdev->dev, "found no memory resource\n");
  96                 err = -ENXIO;
  97                 goto out;
  98         }
  99         if (!devm_request_mem_region(&pdev->dev, res_mem->start,
 100                                         resource_size(res_mem),
 101                                      res_mem->name)) {
 102                 dev_err(&pdev->dev, "request_mem_region failed\n");
 103                 err = -ENXIO;
 104                 goto out;
 105         }
 106         gpio->register_base = (u64)devm_ioremap(&pdev->dev, res_mem->start,
 107                                                 resource_size(res_mem));
 108
 109         pdev->dev.platform_data = chip;
 110         chip->label = "octeon-gpio";
 111         chip->dev = &pdev->dev;
 112         chip->owner = THIS_MODULE;
 113         chip->base = 0;
 114         chip->can_sleep = 0;
 115         chip->ngpio = 20;
 116         chip->direction_input = octeon_gpio_dir_in;
 117         chip->get = octeon_gpio_get;
 118         chip->direction_output = octeon_gpio_dir_out;
 119         chip->set = octeon_gpio_set;
 120         err = gpiochip_add(chip);
 121         if (err)
 122                 goto out;
 123
 124         dev_info(&pdev->dev, "OCTEON GPIO driver probed.\n");
 125 out:
 126         return err;
 127 }
 128
 129 static int octeon_gpio_remove(struct platform_device *pdev)
 130 {
 131         struct gpio_chip *chip = pdev->dev.platform_data;
 132         return gpiochip_remove(chip);
 133 }
 134
 135 static struct of_device_id octeon_gpio_match[] = {
 136         {
 137                 .compatible = "cavium,octeon-3860-gpio",
 138         },
 139         {},
 140 };
 141 MODULE_DEVICE_TABLE(of, octeon_gpio_match);
 142
 143 static struct platform_driver octeon_gpio_driver = {
 144         .driver = {
 145                 .name           = "octeon_gpio",
 146                 .owner          = THIS_MODULE,
 147                 .of_match_table = octeon_gpio_match,
 148         },
 149         .probe          = octeon_gpio_probe,
 150         .remove         = octeon_gpio_remove,
 151 };
 152
 153 module_platform_driver(octeon_gpio_driver);
 154
 155 MODULE_DESCRIPTION("Cavium Inc. OCTEON GPIO Driver");
 156 MODULE_AUTHOR("David Daney");
 157 MODULE_LICENSE("GPL");