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/driver.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 = gpiochip_get_data(chip); 45 46 cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), 0); 47 return 0; 48 } 49 50 static int octeon_gpio_set(struct gpio_chip *chip, unsigned int offset, 51 int value) 52 { 53 struct octeon_gpio *gpio = gpiochip_get_data(chip); 54 u64 mask = 1ull << offset; 55 u64 reg = gpio->register_base + (value ? TX_SET : TX_CLEAR); 56 cvmx_write_csr(reg, mask); 57 58 return 0; 59 } 60 61 static int octeon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, 62 int value) 63 { 64 struct octeon_gpio *gpio = gpiochip_get_data(chip); 65 union cvmx_gpio_bit_cfgx cfgx; 66 67 octeon_gpio_set(chip, offset, value); 68 69 cfgx.u64 = 0; 70 cfgx.s.tx_oe = 1; 71 72 cvmx_write_csr(gpio->register_base + bit_cfg_reg(offset), cfgx.u64); 73 return 0; 74 } 75 76 static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset) 77 { 78 struct octeon_gpio *gpio = gpiochip_get_data(chip); 79 u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT); 80 81 return ((1ull << offset) & read_bits) != 0; 82 } 83 84 static int octeon_gpio_probe(struct platform_device *pdev) 85 { 86 struct octeon_gpio *gpio; 87 struct gpio_chip *chip; 88 void __iomem *reg_base; 89 int err = 0; 90 91 gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL); 92 if (!gpio) 93 return -ENOMEM; 94 chip = &gpio->chip; 95 96 reg_base = devm_platform_ioremap_resource(pdev, 0); 97 if (IS_ERR(reg_base)) 98 return PTR_ERR(reg_base); 99 100 gpio->register_base = (u64)reg_base; 101 pdev->dev.platform_data = chip; 102 chip->label = "octeon-gpio"; 103 chip->parent = &pdev->dev; 104 chip->owner = THIS_MODULE; 105 chip->base = 0; 106 chip->can_sleep = false; 107 chip->ngpio = 20; 108 chip->direction_input = octeon_gpio_dir_in; 109 chip->get = octeon_gpio_get; 110 chip->direction_output = octeon_gpio_dir_out; 111 chip->set = octeon_gpio_set; 112 err = devm_gpiochip_add_data(&pdev->dev, chip, gpio); 113 if (err) 114 return err; 115 116 dev_info(&pdev->dev, "OCTEON GPIO driver probed.\n"); 117 return 0; 118 } 119 120 static const struct of_device_id octeon_gpio_match[] = { 121 { 122 .compatible = "cavium,octeon-3860-gpio", 123 }, 124 {}, 125 }; 126 MODULE_DEVICE_TABLE(of, octeon_gpio_match); 127 128 static struct platform_driver octeon_gpio_driver = { 129 .driver = { 130 .name = "octeon_gpio", 131 .of_match_table = octeon_gpio_match, 132 }, 133 .probe = octeon_gpio_probe, 134 }; 135 136 module_platform_driver(octeon_gpio_driver); 137 138 MODULE_DESCRIPTION("Cavium Inc. OCTEON GPIO Driver"); 139 MODULE_AUTHOR("David Daney"); 140 MODULE_LICENSE("GPL"); 141