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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Loongson-2F/3A/3B GPIO Support4 *5 * Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@st.com>6 * Copyright (c) 2008-2010 Arnaud Patard <apatard@mandriva.com>7 * Copyright (c) 2013 Hongbing Hu <huhb@lemote.com>8 * Copyright (c) 2014 Huacai Chen <chenhc@lemote.com>9 */10 11#include <linux/kernel.h>12#include <linux/init.h>13#include <linux/module.h>14#include <linux/spinlock.h>15#include <linux/err.h>16#include <linux/gpio/driver.h>17#include <linux/platform_device.h>18#include <linux/bitops.h>19#include <asm/types.h>20#include <loongson.h>21 22#define STLS2F_N_GPIO 423#define STLS3A_N_GPIO 1624 25#ifdef CONFIG_CPU_LOONGSON6426#define LOONGSON_N_GPIO STLS3A_N_GPIO27#else28#define LOONGSON_N_GPIO STLS2F_N_GPIO29#endif30 31/*32 * Offset into the register where we read lines, we write them from offset 0.33 * This offset is the only thing that stand between us and using34 * GPIO_GENERIC.35 */36#define LOONGSON_GPIO_IN_OFFSET 1637 38static DEFINE_SPINLOCK(gpio_lock);39 40static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)41{42 u32 val;43 44 spin_lock(&gpio_lock);45 val = LOONGSON_GPIODATA;46 spin_unlock(&gpio_lock);47 48 return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));49}50 51static void loongson_gpio_set_value(struct gpio_chip *chip,52 unsigned gpio, int value)53{54 u32 val;55 56 spin_lock(&gpio_lock);57 val = LOONGSON_GPIODATA;58 if (value)59 val |= BIT(gpio);60 else61 val &= ~BIT(gpio);62 LOONGSON_GPIODATA = val;63 spin_unlock(&gpio_lock);64}65 66static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)67{68 u32 temp;69 70 spin_lock(&gpio_lock);71 temp = LOONGSON_GPIOIE;72 temp |= BIT(gpio);73 LOONGSON_GPIOIE = temp;74 spin_unlock(&gpio_lock);75 76 return 0;77}78 79static int loongson_gpio_direction_output(struct gpio_chip *chip,80 unsigned gpio, int level)81{82 u32 temp;83 84 loongson_gpio_set_value(chip, gpio, level);85 spin_lock(&gpio_lock);86 temp = LOONGSON_GPIOIE;87 temp &= ~BIT(gpio);88 LOONGSON_GPIOIE = temp;89 spin_unlock(&gpio_lock);90 91 return 0;92}93 94static int loongson_gpio_probe(struct platform_device *pdev)95{96 struct gpio_chip *gc;97 struct device *dev = &pdev->dev;98 99 gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);100 if (!gc)101 return -ENOMEM;102 103 gc->label = "loongson-gpio-chip";104 gc->base = 0;105 gc->ngpio = LOONGSON_N_GPIO;106 gc->get = loongson_gpio_get_value;107 gc->set = loongson_gpio_set_value;108 gc->direction_input = loongson_gpio_direction_input;109 gc->direction_output = loongson_gpio_direction_output;110 111 return gpiochip_add_data(gc, NULL);112}113 114static struct platform_driver loongson_gpio_driver = {115 .driver = {116 .name = "loongson-gpio",117 },118 .probe = loongson_gpio_probe,119};120 121static int __init loongson_gpio_setup(void)122{123 struct platform_device *pdev;124 int ret;125 126 ret = platform_driver_register(&loongson_gpio_driver);127 if (ret) {128 pr_err("error registering loongson GPIO driver\n");129 return ret;130 }131 132 pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);133 return PTR_ERR_OR_ZERO(pdev);134}135postcore_initcall(loongson_gpio_setup);136