1 /* 2 * GPIO controller in LSI ZEVIO SoCs. 3 * 4 * Author: Fabian Vogt <fabian@ritter-vogt.de> 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 #include <linux/spinlock.h> 12 #include <linux/errno.h> 13 #include <linux/init.h> 14 #include <linux/bitops.h> 15 #include <linux/io.h> 16 #include <linux/of_device.h> 17 #include <linux/of_gpio.h> 18 #include <linux/slab.h> 19 #include <linux/gpio.h> 20 21 /* 22 * Memory layout: 23 * This chip has four gpio sections, each controls 8 GPIOs. 24 * Bit 0 in section 0 is GPIO 0, bit 2 in section 1 is GPIO 10. 25 * Disclaimer: Reverse engineered! 26 * For more information refer to: 27 * http://hackspire.unsads.com/wiki/index.php/Memory-mapped_I/O_ports#90000000_-_General_Purpose_I.2FO_.28GPIO.29 28 * 29 * 0x00-0x3F: Section 0 30 * +0x00: Masked interrupt status (read-only) 31 * +0x04: R: Interrupt status W: Reset interrupt status 32 * +0x08: R: Interrupt mask W: Mask interrupt 33 * +0x0C: W: Unmask interrupt (write-only) 34 * +0x10: Direction: I/O=1/0 35 * +0x14: Output 36 * +0x18: Input (read-only) 37 * +0x20: R: Level interrupt W: Set as level interrupt 38 * 0x40-0x7F: Section 1 39 * 0x80-0xBF: Section 2 40 * 0xC0-0xFF: Section 3 41 */ 42 43 #define ZEVIO_GPIO_SECTION_SIZE 0x40 44 45 /* Offsets to various registers */ 46 #define ZEVIO_GPIO_INT_MASKED_STATUS 0x00 47 #define ZEVIO_GPIO_INT_STATUS 0x04 48 #define ZEVIO_GPIO_INT_UNMASK 0x08 49 #define ZEVIO_GPIO_INT_MASK 0x0C 50 #define ZEVIO_GPIO_DIRECTION 0x10 51 #define ZEVIO_GPIO_OUTPUT 0x14 52 #define ZEVIO_GPIO_INPUT 0x18 53 #define ZEVIO_GPIO_INT_STICKY 0x20 54 55 /* Bit number of GPIO in its section */ 56 #define ZEVIO_GPIO_BIT(gpio) (gpio&7) 57 58 struct zevio_gpio { 59 spinlock_t lock; 60 struct of_mm_gpio_chip chip; 61 }; 62 63 static inline u32 zevio_gpio_port_get(struct zevio_gpio *c, unsigned pin, 64 unsigned port_offset) 65 { 66 unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE; 67 return readl(IOMEM(c->chip.regs + section_offset + port_offset)); 68 } 69 70 static inline void zevio_gpio_port_set(struct zevio_gpio *c, unsigned pin, 71 unsigned port_offset, u32 val) 72 { 73 unsigned section_offset = ((pin >> 3) & 3)*ZEVIO_GPIO_SECTION_SIZE; 74 writel(val, IOMEM(c->chip.regs + section_offset + port_offset)); 75 } 76 77 /* Functions for struct gpio_chip */ 78 static int zevio_gpio_get(struct gpio_chip *chip, unsigned pin) 79 { 80 struct zevio_gpio *controller = gpiochip_get_data(chip); 81 u32 val, dir; 82 83 spin_lock(&controller->lock); 84 dir = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); 85 if (dir & BIT(ZEVIO_GPIO_BIT(pin))) 86 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_INPUT); 87 else 88 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); 89 spin_unlock(&controller->lock); 90 91 return (val >> ZEVIO_GPIO_BIT(pin)) & 0x1; 92 } 93 94 static void zevio_gpio_set(struct gpio_chip *chip, unsigned pin, int value) 95 { 96 struct zevio_gpio *controller = gpiochip_get_data(chip); 97 u32 val; 98 99 spin_lock(&controller->lock); 100 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); 101 if (value) 102 val |= BIT(ZEVIO_GPIO_BIT(pin)); 103 else 104 val &= ~BIT(ZEVIO_GPIO_BIT(pin)); 105 106 zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val); 107 spin_unlock(&controller->lock); 108 } 109 110 static int zevio_gpio_direction_input(struct gpio_chip *chip, unsigned pin) 111 { 112 struct zevio_gpio *controller = gpiochip_get_data(chip); 113 u32 val; 114 115 spin_lock(&controller->lock); 116 117 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); 118 val |= BIT(ZEVIO_GPIO_BIT(pin)); 119 zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val); 120 121 spin_unlock(&controller->lock); 122 123 return 0; 124 } 125 126 static int zevio_gpio_direction_output(struct gpio_chip *chip, 127 unsigned pin, int value) 128 { 129 struct zevio_gpio *controller = gpiochip_get_data(chip); 130 u32 val; 131 132 spin_lock(&controller->lock); 133 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_OUTPUT); 134 if (value) 135 val |= BIT(ZEVIO_GPIO_BIT(pin)); 136 else 137 val &= ~BIT(ZEVIO_GPIO_BIT(pin)); 138 139 zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_OUTPUT, val); 140 val = zevio_gpio_port_get(controller, pin, ZEVIO_GPIO_DIRECTION); 141 val &= ~BIT(ZEVIO_GPIO_BIT(pin)); 142 zevio_gpio_port_set(controller, pin, ZEVIO_GPIO_DIRECTION, val); 143 144 spin_unlock(&controller->lock); 145 146 return 0; 147 } 148 149 static int zevio_gpio_to_irq(struct gpio_chip *chip, unsigned pin) 150 { 151 /* 152 * TODO: Implement IRQs. 153 * Not implemented yet due to weird lockups 154 */ 155 156 return -ENXIO; 157 } 158 159 static const struct gpio_chip zevio_gpio_chip = { 160 .direction_input = zevio_gpio_direction_input, 161 .direction_output = zevio_gpio_direction_output, 162 .set = zevio_gpio_set, 163 .get = zevio_gpio_get, 164 .to_irq = zevio_gpio_to_irq, 165 .base = 0, 166 .owner = THIS_MODULE, 167 .ngpio = 32, 168 .of_gpio_n_cells = 2, 169 }; 170 171 /* Initialization */ 172 static int zevio_gpio_probe(struct platform_device *pdev) 173 { 174 struct zevio_gpio *controller; 175 int status, i; 176 177 controller = devm_kzalloc(&pdev->dev, sizeof(*controller), GFP_KERNEL); 178 if (!controller) 179 return -ENOMEM; 180 181 platform_set_drvdata(pdev, controller); 182 183 /* Copy our reference */ 184 controller->chip.gc = zevio_gpio_chip; 185 controller->chip.gc.parent = &pdev->dev; 186 187 status = of_mm_gpiochip_add_data(pdev->dev.of_node, 188 &(controller->chip), 189 controller); 190 if (status) { 191 dev_err(&pdev->dev, "failed to add gpiochip: %d\n", status); 192 return status; 193 } 194 195 spin_lock_init(&controller->lock); 196 197 /* Disable interrupts, they only cause errors */ 198 for (i = 0; i < controller->chip.gc.ngpio; i += 8) 199 zevio_gpio_port_set(controller, i, ZEVIO_GPIO_INT_MASK, 0xFF); 200 201 dev_dbg(controller->chip.gc.parent, "ZEVIO GPIO controller set up!\n"); 202 203 return 0; 204 } 205 206 static const struct of_device_id zevio_gpio_of_match[] = { 207 { .compatible = "lsi,zevio-gpio", }, 208 { }, 209 }; 210 211 static struct platform_driver zevio_gpio_driver = { 212 .driver = { 213 .name = "gpio-zevio", 214 .of_match_table = zevio_gpio_of_match, 215 .suppress_bind_attrs = true, 216 }, 217 .probe = zevio_gpio_probe, 218 }; 219 builtin_platform_driver(zevio_gpio_driver); 220