1 /* 2 * Xilinx gpio driver for xps/axi_gpio IP. 3 * 4 * Copyright 2008 - 2013 Xilinx, Inc. 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 8 * as published by the Free Software Foundation. 9 * 10 * You should have received a copy of the GNU General Public License 11 * along with this program; if not, write to the Free Software 12 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 13 */ 14 15 #include <linux/bitops.h> 16 #include <linux/init.h> 17 #include <linux/errno.h> 18 #include <linux/module.h> 19 #include <linux/of_device.h> 20 #include <linux/of_platform.h> 21 #include <linux/of_gpio.h> 22 #include <linux/io.h> 23 #include <linux/gpio.h> 24 #include <linux/slab.h> 25 26 /* Register Offset Definitions */ 27 #define XGPIO_DATA_OFFSET (0x0) /* Data register */ 28 #define XGPIO_TRI_OFFSET (0x4) /* I/O direction register */ 29 30 #define XGPIO_CHANNEL_OFFSET 0x8 31 32 /* Read/Write access to the GPIO registers */ 33 #if defined(CONFIG_ARCH_ZYNQ) || defined(CONFIG_X86) 34 # define xgpio_readreg(offset) readl(offset) 35 # define xgpio_writereg(offset, val) writel(val, offset) 36 #else 37 # define xgpio_readreg(offset) __raw_readl(offset) 38 # define xgpio_writereg(offset, val) __raw_writel(val, offset) 39 #endif 40 41 /** 42 * struct xgpio_instance - Stores information about GPIO device 43 * @mmchip: OF GPIO chip for memory mapped banks 44 * @gpio_width: GPIO width for every channel 45 * @gpio_state: GPIO state shadow register 46 * @gpio_dir: GPIO direction shadow register 47 * @gpio_lock: Lock used for synchronization 48 */ 49 struct xgpio_instance { 50 struct of_mm_gpio_chip mmchip; 51 unsigned int gpio_width[2]; 52 u32 gpio_state[2]; 53 u32 gpio_dir[2]; 54 spinlock_t gpio_lock[2]; 55 }; 56 57 static inline int xgpio_index(struct xgpio_instance *chip, int gpio) 58 { 59 if (gpio >= chip->gpio_width[0]) 60 return 1; 61 62 return 0; 63 } 64 65 static inline int xgpio_regoffset(struct xgpio_instance *chip, int gpio) 66 { 67 if (xgpio_index(chip, gpio)) 68 return XGPIO_CHANNEL_OFFSET; 69 70 return 0; 71 } 72 73 static inline int xgpio_offset(struct xgpio_instance *chip, int gpio) 74 { 75 if (xgpio_index(chip, gpio)) 76 return gpio - chip->gpio_width[0]; 77 78 return gpio; 79 } 80 81 /** 82 * xgpio_get - Read the specified signal of the GPIO device. 83 * @gc: Pointer to gpio_chip device structure. 84 * @gpio: GPIO signal number. 85 * 86 * This function reads the specified signal of the GPIO device. 87 * 88 * Return: 89 * 0 if direction of GPIO signals is set as input otherwise it 90 * returns negative error value. 91 */ 92 static int xgpio_get(struct gpio_chip *gc, unsigned int gpio) 93 { 94 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); 95 struct xgpio_instance *chip = 96 container_of(mm_gc, struct xgpio_instance, mmchip); 97 u32 val; 98 99 val = xgpio_readreg(mm_gc->regs + XGPIO_DATA_OFFSET + 100 xgpio_regoffset(chip, gpio)); 101 102 return !!(val & BIT(xgpio_offset(chip, gpio))); 103 } 104 105 /** 106 * xgpio_set - Write the specified signal of the GPIO device. 107 * @gc: Pointer to gpio_chip device structure. 108 * @gpio: GPIO signal number. 109 * @val: Value to be written to specified signal. 110 * 111 * This function writes the specified value in to the specified signal of the 112 * GPIO device. 113 */ 114 static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val) 115 { 116 unsigned long flags; 117 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); 118 struct xgpio_instance *chip = 119 container_of(mm_gc, struct xgpio_instance, mmchip); 120 int index = xgpio_index(chip, gpio); 121 int offset = xgpio_offset(chip, gpio); 122 123 spin_lock_irqsave(&chip->gpio_lock[index], flags); 124 125 /* Write to GPIO signal and set its direction to output */ 126 if (val) 127 chip->gpio_state[index] |= BIT(offset); 128 else 129 chip->gpio_state[index] &= ~BIT(offset); 130 131 xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + 132 xgpio_regoffset(chip, gpio), chip->gpio_state[index]); 133 134 spin_unlock_irqrestore(&chip->gpio_lock[index], flags); 135 } 136 137 /** 138 * xgpio_dir_in - Set the direction of the specified GPIO signal as input. 139 * @gc: Pointer to gpio_chip device structure. 140 * @gpio: GPIO signal number. 141 * 142 * Return: 143 * 0 - if direction of GPIO signals is set as input 144 * otherwise it returns negative error value. 145 */ 146 static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio) 147 { 148 unsigned long flags; 149 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); 150 struct xgpio_instance *chip = 151 container_of(mm_gc, struct xgpio_instance, mmchip); 152 int index = xgpio_index(chip, gpio); 153 int offset = xgpio_offset(chip, gpio); 154 155 spin_lock_irqsave(&chip->gpio_lock[index], flags); 156 157 /* Set the GPIO bit in shadow register and set direction as input */ 158 chip->gpio_dir[index] |= BIT(offset); 159 xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + 160 xgpio_regoffset(chip, gpio), chip->gpio_dir[index]); 161 162 spin_unlock_irqrestore(&chip->gpio_lock[index], flags); 163 164 return 0; 165 } 166 167 /** 168 * xgpio_dir_out - Set the direction of the specified GPIO signal as output. 169 * @gc: Pointer to gpio_chip device structure. 170 * @gpio: GPIO signal number. 171 * @val: Value to be written to specified signal. 172 * 173 * This function sets the direction of specified GPIO signal as output. 174 * 175 * Return: 176 * If all GPIO signals of GPIO chip is configured as input then it returns 177 * error otherwise it returns 0. 178 */ 179 static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) 180 { 181 unsigned long flags; 182 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); 183 struct xgpio_instance *chip = 184 container_of(mm_gc, struct xgpio_instance, mmchip); 185 int index = xgpio_index(chip, gpio); 186 int offset = xgpio_offset(chip, gpio); 187 188 spin_lock_irqsave(&chip->gpio_lock[index], flags); 189 190 /* Write state of GPIO signal */ 191 if (val) 192 chip->gpio_state[index] |= BIT(offset); 193 else 194 chip->gpio_state[index] &= ~BIT(offset); 195 xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + 196 xgpio_regoffset(chip, gpio), chip->gpio_state[index]); 197 198 /* Clear the GPIO bit in shadow register and set direction as output */ 199 chip->gpio_dir[index] &= ~BIT(offset); 200 xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + 201 xgpio_regoffset(chip, gpio), chip->gpio_dir[index]); 202 203 spin_unlock_irqrestore(&chip->gpio_lock[index], flags); 204 205 return 0; 206 } 207 208 /** 209 * xgpio_save_regs - Set initial values of GPIO pins 210 * @mm_gc: Pointer to memory mapped GPIO chip structure 211 */ 212 static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc) 213 { 214 struct xgpio_instance *chip = 215 container_of(mm_gc, struct xgpio_instance, mmchip); 216 217 xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET, chip->gpio_state[0]); 218 xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]); 219 220 if (!chip->gpio_width[1]) 221 return; 222 223 xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET, 224 chip->gpio_state[1]); 225 xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET, 226 chip->gpio_dir[1]); 227 } 228 229 /** 230 * xgpio_remove - Remove method for the GPIO device. 231 * @pdev: pointer to the platform device 232 * 233 * This function remove gpiochips and frees all the allocated resources. 234 * 235 * Return: 0 always 236 */ 237 static int xgpio_remove(struct platform_device *pdev) 238 { 239 struct xgpio_instance *chip = platform_get_drvdata(pdev); 240 241 of_mm_gpiochip_remove(&chip->mmchip); 242 243 return 0; 244 } 245 246 /** 247 * xgpio_of_probe - Probe method for the GPIO device. 248 * @pdev: pointer to the platform device 249 * 250 * Return: 251 * It returns 0, if the driver is bound to the GPIO device, or 252 * a negative value if there is an error. 253 */ 254 static int xgpio_probe(struct platform_device *pdev) 255 { 256 struct xgpio_instance *chip; 257 int status = 0; 258 struct device_node *np = pdev->dev.of_node; 259 u32 is_dual; 260 261 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); 262 if (!chip) 263 return -ENOMEM; 264 265 platform_set_drvdata(pdev, chip); 266 267 /* Update GPIO state shadow register with default value */ 268 of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state[0]); 269 270 /* Update GPIO direction shadow register with default value */ 271 if (of_property_read_u32(np, "xlnx,tri-default", &chip->gpio_dir[0])) 272 chip->gpio_dir[0] = 0xFFFFFFFF; 273 274 /* 275 * Check device node and parent device node for device width 276 * and assume default width of 32 277 */ 278 if (of_property_read_u32(np, "xlnx,gpio-width", &chip->gpio_width[0])) 279 chip->gpio_width[0] = 32; 280 281 spin_lock_init(&chip->gpio_lock[0]); 282 283 if (of_property_read_u32(np, "xlnx,is-dual", &is_dual)) 284 is_dual = 0; 285 286 if (is_dual) { 287 /* Update GPIO state shadow register with default value */ 288 of_property_read_u32(np, "xlnx,dout-default-2", 289 &chip->gpio_state[1]); 290 291 /* Update GPIO direction shadow register with default value */ 292 if (of_property_read_u32(np, "xlnx,tri-default-2", 293 &chip->gpio_dir[1])) 294 chip->gpio_dir[1] = 0xFFFFFFFF; 295 296 /* 297 * Check device node and parent device node for device width 298 * and assume default width of 32 299 */ 300 if (of_property_read_u32(np, "xlnx,gpio2-width", 301 &chip->gpio_width[1])) 302 chip->gpio_width[1] = 32; 303 304 spin_lock_init(&chip->gpio_lock[1]); 305 } 306 307 chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1]; 308 chip->mmchip.gc.dev = &pdev->dev; 309 chip->mmchip.gc.direction_input = xgpio_dir_in; 310 chip->mmchip.gc.direction_output = xgpio_dir_out; 311 chip->mmchip.gc.get = xgpio_get; 312 chip->mmchip.gc.set = xgpio_set; 313 314 chip->mmchip.save_regs = xgpio_save_regs; 315 316 /* Call the OF gpio helper to setup and register the GPIO device */ 317 status = of_mm_gpiochip_add(np, &chip->mmchip); 318 if (status) { 319 pr_err("%s: error in probe function with status %d\n", 320 np->full_name, status); 321 return status; 322 } 323 324 return 0; 325 } 326 327 static const struct of_device_id xgpio_of_match[] = { 328 { .compatible = "xlnx,xps-gpio-1.00.a", }, 329 { /* end of list */ }, 330 }; 331 332 MODULE_DEVICE_TABLE(of, xgpio_of_match); 333 334 static struct platform_driver xgpio_plat_driver = { 335 .probe = xgpio_probe, 336 .remove = xgpio_remove, 337 .driver = { 338 .name = "gpio-xilinx", 339 .of_match_table = xgpio_of_match, 340 }, 341 }; 342 343 static int __init xgpio_init(void) 344 { 345 return platform_driver_register(&xgpio_plat_driver); 346 } 347 348 subsys_initcall(xgpio_init); 349 350 static void __exit xgpio_exit(void) 351 { 352 platform_driver_unregister(&xgpio_plat_driver); 353 } 354 module_exit(xgpio_exit); 355 356 MODULE_AUTHOR("Xilinx, Inc."); 357 MODULE_DESCRIPTION("Xilinx GPIO driver"); 358 MODULE_LICENSE("GPL"); 359