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 inline struct lpc18xx_gpio_chip *to_lpc18xx_gpio(struct gpio_chip *chip) 35 { 36 return container_of(chip, struct lpc18xx_gpio_chip, gpio); 37 } 38 39 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 40 { 41 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 42 writeb(value ? 1 : 0, gc->base + offset); 43 } 44 45 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset) 46 { 47 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 48 return !!readb(gc->base + offset); 49 } 50 51 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset, 52 bool out) 53 { 54 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 55 unsigned long flags; 56 u32 port, pin, dir; 57 58 port = offset / LPC18XX_PINS_PER_PORT; 59 pin = offset % LPC18XX_PINS_PER_PORT; 60 61 spin_lock_irqsave(&gc->lock, flags); 62 dir = readl(gc->base + LPC18XX_REG_DIR(port)); 63 if (out) 64 dir |= BIT(pin); 65 else 66 dir &= ~BIT(pin); 67 writel(dir, gc->base + LPC18XX_REG_DIR(port)); 68 spin_unlock_irqrestore(&gc->lock, flags); 69 70 return 0; 71 } 72 73 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip, 74 unsigned offset) 75 { 76 return lpc18xx_gpio_direction(chip, offset, false); 77 } 78 79 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip, 80 unsigned offset, int value) 81 { 82 lpc18xx_gpio_set(chip, offset, value); 83 return lpc18xx_gpio_direction(chip, offset, true); 84 } 85 86 static struct gpio_chip lpc18xx_chip = { 87 .label = "lpc18xx/43xx-gpio", 88 .request = gpiochip_generic_request, 89 .free = gpiochip_generic_free, 90 .direction_input = lpc18xx_gpio_direction_input, 91 .direction_output = lpc18xx_gpio_direction_output, 92 .set = lpc18xx_gpio_set, 93 .get = lpc18xx_gpio_get, 94 .ngpio = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT, 95 .owner = THIS_MODULE, 96 }; 97 98 static int lpc18xx_gpio_probe(struct platform_device *pdev) 99 { 100 struct lpc18xx_gpio_chip *gc; 101 struct resource *res; 102 int ret; 103 104 gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL); 105 if (!gc) 106 return -ENOMEM; 107 108 gc->gpio = lpc18xx_chip; 109 platform_set_drvdata(pdev, gc); 110 111 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 112 gc->base = devm_ioremap_resource(&pdev->dev, res); 113 if (IS_ERR(gc->base)) 114 return PTR_ERR(gc->base); 115 116 gc->clk = devm_clk_get(&pdev->dev, NULL); 117 if (IS_ERR(gc->clk)) { 118 dev_err(&pdev->dev, "input clock not found\n"); 119 return PTR_ERR(gc->clk); 120 } 121 122 ret = clk_prepare_enable(gc->clk); 123 if (ret) { 124 dev_err(&pdev->dev, "unable to enable clock\n"); 125 return ret; 126 } 127 128 spin_lock_init(&gc->lock); 129 130 gc->gpio.dev = &pdev->dev; 131 132 ret = gpiochip_add(&gc->gpio); 133 if (ret) { 134 dev_err(&pdev->dev, "failed to add gpio chip\n"); 135 clk_disable_unprepare(gc->clk); 136 return ret; 137 } 138 139 return 0; 140 } 141 142 static int lpc18xx_gpio_remove(struct platform_device *pdev) 143 { 144 struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev); 145 146 gpiochip_remove(&gc->gpio); 147 clk_disable_unprepare(gc->clk); 148 149 return 0; 150 } 151 152 static const struct of_device_id lpc18xx_gpio_match[] = { 153 { .compatible = "nxp,lpc1850-gpio" }, 154 { } 155 }; 156 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match); 157 158 static struct platform_driver lpc18xx_gpio_driver = { 159 .probe = lpc18xx_gpio_probe, 160 .remove = lpc18xx_gpio_remove, 161 .driver = { 162 .name = "lpc18xx-gpio", 163 .of_match_table = lpc18xx_gpio_match, 164 }, 165 }; 166 module_platform_driver(lpc18xx_gpio_driver); 167 168 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); 169 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx"); 170 MODULE_LICENSE("GPL v2"); 171