1 /* 2 * GPIO driver for NXP LPC18xx/43xx. 3 * 4 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/gpio/driver.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/of.h> 17 #include <linux/of_gpio.h> 18 #include <linux/pinctrl/consumer.h> 19 #include <linux/platform_device.h> 20 21 /* LPC18xx GPIO register offsets */ 22 #define LPC18XX_REG_DIR(n) (0x2000 + n * sizeof(u32)) 23 24 #define LPC18XX_MAX_PORTS 8 25 #define LPC18XX_PINS_PER_PORT 32 26 27 struct lpc18xx_gpio_chip { 28 struct gpio_chip gpio; 29 void __iomem *base; 30 struct clk *clk; 31 spinlock_t lock; 32 }; 33 34 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 35 { 36 struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip); 37 writeb(value ? 1 : 0, gc->base + offset); 38 } 39 40 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset) 41 { 42 struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip); 43 return !!readb(gc->base + offset); 44 } 45 46 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset, 47 bool out) 48 { 49 struct lpc18xx_gpio_chip *gc = gpiochip_get_data(chip); 50 unsigned long flags; 51 u32 port, pin, dir; 52 53 port = offset / LPC18XX_PINS_PER_PORT; 54 pin = offset % LPC18XX_PINS_PER_PORT; 55 56 spin_lock_irqsave(&gc->lock, flags); 57 dir = readl(gc->base + LPC18XX_REG_DIR(port)); 58 if (out) 59 dir |= BIT(pin); 60 else 61 dir &= ~BIT(pin); 62 writel(dir, gc->base + LPC18XX_REG_DIR(port)); 63 spin_unlock_irqrestore(&gc->lock, flags); 64 65 return 0; 66 } 67 68 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip, 69 unsigned offset) 70 { 71 return lpc18xx_gpio_direction(chip, offset, false); 72 } 73 74 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip, 75 unsigned offset, int value) 76 { 77 lpc18xx_gpio_set(chip, offset, value); 78 return lpc18xx_gpio_direction(chip, offset, true); 79 } 80 81 static struct gpio_chip lpc18xx_chip = { 82 .label = "lpc18xx/43xx-gpio", 83 .request = gpiochip_generic_request, 84 .free = gpiochip_generic_free, 85 .direction_input = lpc18xx_gpio_direction_input, 86 .direction_output = lpc18xx_gpio_direction_output, 87 .set = lpc18xx_gpio_set, 88 .get = lpc18xx_gpio_get, 89 .ngpio = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT, 90 .owner = THIS_MODULE, 91 }; 92 93 static int lpc18xx_gpio_probe(struct platform_device *pdev) 94 { 95 struct lpc18xx_gpio_chip *gc; 96 struct resource *res; 97 int ret; 98 99 gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL); 100 if (!gc) 101 return -ENOMEM; 102 103 gc->gpio = lpc18xx_chip; 104 platform_set_drvdata(pdev, gc); 105 106 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 107 gc->base = devm_ioremap_resource(&pdev->dev, res); 108 if (IS_ERR(gc->base)) 109 return PTR_ERR(gc->base); 110 111 gc->clk = devm_clk_get(&pdev->dev, NULL); 112 if (IS_ERR(gc->clk)) { 113 dev_err(&pdev->dev, "input clock not found\n"); 114 return PTR_ERR(gc->clk); 115 } 116 117 ret = clk_prepare_enable(gc->clk); 118 if (ret) { 119 dev_err(&pdev->dev, "unable to enable clock\n"); 120 return ret; 121 } 122 123 spin_lock_init(&gc->lock); 124 125 gc->gpio.parent = &pdev->dev; 126 127 ret = gpiochip_add_data(&gc->gpio, gc); 128 if (ret) { 129 dev_err(&pdev->dev, "failed to add gpio chip\n"); 130 clk_disable_unprepare(gc->clk); 131 return ret; 132 } 133 134 return 0; 135 } 136 137 static int lpc18xx_gpio_remove(struct platform_device *pdev) 138 { 139 struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev); 140 141 gpiochip_remove(&gc->gpio); 142 clk_disable_unprepare(gc->clk); 143 144 return 0; 145 } 146 147 static const struct of_device_id lpc18xx_gpio_match[] = { 148 { .compatible = "nxp,lpc1850-gpio" }, 149 { } 150 }; 151 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match); 152 153 static struct platform_driver lpc18xx_gpio_driver = { 154 .probe = lpc18xx_gpio_probe, 155 .remove = lpc18xx_gpio_remove, 156 .driver = { 157 .name = "lpc18xx-gpio", 158 .of_match_table = lpc18xx_gpio_match, 159 }, 160 }; 161 module_platform_driver(lpc18xx_gpio_driver); 162 163 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); 164 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx"); 165 MODULE_LICENSE("GPL v2"); 166