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 int lpc18xx_gpio_request(struct gpio_chip *chip, unsigned offset) 40 { 41 return pinctrl_request_gpio(offset); 42 } 43 44 static void lpc18xx_gpio_free(struct gpio_chip *chip, unsigned offset) 45 { 46 pinctrl_free_gpio(offset); 47 } 48 49 static void lpc18xx_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 50 { 51 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 52 writeb(value ? 1 : 0, gc->base + offset); 53 } 54 55 static int lpc18xx_gpio_get(struct gpio_chip *chip, unsigned offset) 56 { 57 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 58 return !!readb(gc->base + offset); 59 } 60 61 static int lpc18xx_gpio_direction(struct gpio_chip *chip, unsigned offset, 62 bool out) 63 { 64 struct lpc18xx_gpio_chip *gc = to_lpc18xx_gpio(chip); 65 unsigned long flags; 66 u32 port, pin, dir; 67 68 port = offset / LPC18XX_PINS_PER_PORT; 69 pin = offset % LPC18XX_PINS_PER_PORT; 70 71 spin_lock_irqsave(&gc->lock, flags); 72 dir = readl(gc->base + LPC18XX_REG_DIR(port)); 73 if (out) 74 dir |= BIT(pin); 75 else 76 dir &= ~BIT(pin); 77 writel(dir, gc->base + LPC18XX_REG_DIR(port)); 78 spin_unlock_irqrestore(&gc->lock, flags); 79 80 return 0; 81 } 82 83 static int lpc18xx_gpio_direction_input(struct gpio_chip *chip, 84 unsigned offset) 85 { 86 return lpc18xx_gpio_direction(chip, offset, false); 87 } 88 89 static int lpc18xx_gpio_direction_output(struct gpio_chip *chip, 90 unsigned offset, int value) 91 { 92 lpc18xx_gpio_set(chip, offset, value); 93 return lpc18xx_gpio_direction(chip, offset, true); 94 } 95 96 static struct gpio_chip lpc18xx_chip = { 97 .label = "lpc18xx/43xx-gpio", 98 .request = lpc18xx_gpio_request, 99 .free = lpc18xx_gpio_free, 100 .direction_input = lpc18xx_gpio_direction_input, 101 .direction_output = lpc18xx_gpio_direction_output, 102 .set = lpc18xx_gpio_set, 103 .get = lpc18xx_gpio_get, 104 .ngpio = LPC18XX_MAX_PORTS * LPC18XX_PINS_PER_PORT, 105 .owner = THIS_MODULE, 106 }; 107 108 static int lpc18xx_gpio_probe(struct platform_device *pdev) 109 { 110 struct lpc18xx_gpio_chip *gc; 111 struct resource *res; 112 int ret; 113 114 gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL); 115 if (!gc) 116 return -ENOMEM; 117 118 gc->gpio = lpc18xx_chip; 119 platform_set_drvdata(pdev, gc); 120 121 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 122 gc->base = devm_ioremap_resource(&pdev->dev, res); 123 if (IS_ERR(gc->base)) 124 return PTR_ERR(gc->base); 125 126 gc->clk = devm_clk_get(&pdev->dev, NULL); 127 if (IS_ERR(gc->clk)) { 128 dev_err(&pdev->dev, "input clock not found\n"); 129 return PTR_ERR(gc->clk); 130 } 131 132 ret = clk_prepare_enable(gc->clk); 133 if (ret) { 134 dev_err(&pdev->dev, "unable to enable clock\n"); 135 return ret; 136 } 137 138 spin_lock_init(&gc->lock); 139 140 gc->gpio.dev = &pdev->dev; 141 142 ret = gpiochip_add(&gc->gpio); 143 if (ret) { 144 dev_err(&pdev->dev, "failed to add gpio chip\n"); 145 clk_disable_unprepare(gc->clk); 146 return ret; 147 } 148 149 return 0; 150 } 151 152 static int lpc18xx_gpio_remove(struct platform_device *pdev) 153 { 154 struct lpc18xx_gpio_chip *gc = platform_get_drvdata(pdev); 155 156 gpiochip_remove(&gc->gpio); 157 clk_disable_unprepare(gc->clk); 158 159 return 0; 160 } 161 162 static const struct of_device_id lpc18xx_gpio_match[] = { 163 { .compatible = "nxp,lpc1850-gpio" }, 164 { } 165 }; 166 MODULE_DEVICE_TABLE(of, lpc18xx_gpio_match); 167 168 static struct platform_driver lpc18xx_gpio_driver = { 169 .probe = lpc18xx_gpio_probe, 170 .remove = lpc18xx_gpio_remove, 171 .driver = { 172 .name = "lpc18xx-gpio", 173 .of_match_table = lpc18xx_gpio_match, 174 }, 175 }; 176 module_platform_driver(lpc18xx_gpio_driver); 177 178 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>"); 179 MODULE_DESCRIPTION("GPIO driver for LPC18xx/43xx"); 180 MODULE_LICENSE("GPL v2"); 181