140 lines
3.2 KiB
C
140 lines
3.2 KiB
C
/*
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* Loongson-2F/3A/3B GPIO Support
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*
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* Copyright (c) 2008 Richard Liu, STMicroelectronics <richard.liu@st.com>
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* Copyright (c) 2008-2010 Arnaud Patard <apatard@mandriva.com>
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* Copyright (c) 2013 Hongbing Hu <huhb@lemote.com>
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* Copyright (c) 2014 Huacai Chen <chenhc@lemote.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/err.h>
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#include <linux/gpio/driver.h>
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#include <linux/platform_device.h>
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#include <linux/bitops.h>
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#include <asm/types.h>
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#include <loongson.h>
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#define STLS2F_N_GPIO 4
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#define STLS3A_N_GPIO 16
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#ifdef CONFIG_CPU_LOONGSON3
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#define LOONGSON_N_GPIO STLS3A_N_GPIO
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#else
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#define LOONGSON_N_GPIO STLS2F_N_GPIO
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#endif
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/*
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* Offset into the register where we read lines, we write them from offset 0.
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* This offset is the only thing that stand between us and using
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* GPIO_GENERIC.
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*/
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#define LOONGSON_GPIO_IN_OFFSET 16
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static DEFINE_SPINLOCK(gpio_lock);
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static int loongson_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
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{
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u32 val;
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spin_lock(&gpio_lock);
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val = LOONGSON_GPIODATA;
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spin_unlock(&gpio_lock);
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return !!(val & BIT(gpio + LOONGSON_GPIO_IN_OFFSET));
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}
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static void loongson_gpio_set_value(struct gpio_chip *chip,
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unsigned gpio, int value)
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{
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u32 val;
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spin_lock(&gpio_lock);
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val = LOONGSON_GPIODATA;
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if (value)
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val |= BIT(gpio);
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else
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val &= ~BIT(gpio);
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LOONGSON_GPIODATA = val;
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spin_unlock(&gpio_lock);
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}
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static int loongson_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
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{
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u32 temp;
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spin_lock(&gpio_lock);
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temp = LOONGSON_GPIOIE;
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temp |= BIT(gpio);
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LOONGSON_GPIOIE = temp;
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spin_unlock(&gpio_lock);
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return 0;
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}
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static int loongson_gpio_direction_output(struct gpio_chip *chip,
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unsigned gpio, int level)
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{
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u32 temp;
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loongson_gpio_set_value(chip, gpio, level);
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spin_lock(&gpio_lock);
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temp = LOONGSON_GPIOIE;
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temp &= ~BIT(gpio);
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LOONGSON_GPIOIE = temp;
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spin_unlock(&gpio_lock);
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return 0;
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}
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static int loongson_gpio_probe(struct platform_device *pdev)
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{
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struct gpio_chip *gc;
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struct device *dev = &pdev->dev;
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gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
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if (!gc)
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return -ENOMEM;
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gc->label = "loongson-gpio-chip";
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gc->base = 0;
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gc->ngpio = LOONGSON_N_GPIO;
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gc->get = loongson_gpio_get_value;
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gc->set = loongson_gpio_set_value;
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gc->direction_input = loongson_gpio_direction_input;
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gc->direction_output = loongson_gpio_direction_output;
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return gpiochip_add_data(gc, NULL);
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}
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static struct platform_driver loongson_gpio_driver = {
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.driver = {
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.name = "loongson-gpio",
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},
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.probe = loongson_gpio_probe,
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};
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static int __init loongson_gpio_setup(void)
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{
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struct platform_device *pdev;
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int ret;
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ret = platform_driver_register(&loongson_gpio_driver);
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if (ret) {
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pr_err("error registering loongson GPIO driver\n");
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return ret;
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}
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pdev = platform_device_register_simple("loongson-gpio", -1, NULL, 0);
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return PTR_ERR_OR_ZERO(pdev);
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}
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postcore_initcall(loongson_gpio_setup);
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