1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Raspberry Pi 3 expander GPIO driver 4 * 5 * Uses the firmware mailbox service to communicate with the 6 * GPIO expander on the VPU. 7 * 8 * Copyright (C) 2017 Raspberry Pi Trading Ltd. 9 */ 10 11 #include <linux/err.h> 12 #include <linux/gpio/driver.h> 13 #include <linux/module.h> 14 #include <linux/platform_device.h> 15 #include <soc/bcm2835/raspberrypi-firmware.h> 16 17 #define MODULE_NAME "raspberrypi-exp-gpio" 18 #define NUM_GPIO 8 19 20 #define RPI_EXP_GPIO_BASE 128 21 22 #define RPI_EXP_GPIO_DIR_IN 0 23 #define RPI_EXP_GPIO_DIR_OUT 1 24 25 struct rpi_exp_gpio { 26 struct gpio_chip gc; 27 struct rpi_firmware *fw; 28 }; 29 30 /* VC4 firmware mailbox interface data structures */ 31 32 struct gpio_set_config { 33 u32 gpio; 34 u32 direction; 35 u32 polarity; 36 u32 term_en; 37 u32 term_pull_up; 38 u32 state; 39 }; 40 41 struct gpio_get_config { 42 u32 gpio; 43 u32 direction; 44 u32 polarity; 45 u32 term_en; 46 u32 term_pull_up; 47 }; 48 49 struct gpio_get_set_state { 50 u32 gpio; 51 u32 state; 52 }; 53 54 static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off) 55 { 56 struct rpi_exp_gpio *gpio; 57 struct gpio_get_config get; 58 int ret; 59 60 gpio = gpiochip_get_data(gc); 61 62 get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 63 64 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, 65 &get, sizeof(get)); 66 if (ret || get.gpio != 0) { 67 dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", 68 off, ret, get.gpio); 69 return ret ? ret : -EIO; 70 } 71 return get.polarity; 72 } 73 74 static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off) 75 { 76 struct rpi_exp_gpio *gpio; 77 struct gpio_set_config set_in; 78 int ret; 79 80 gpio = gpiochip_get_data(gc); 81 82 set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 83 set_in.direction = RPI_EXP_GPIO_DIR_IN; 84 set_in.term_en = 0; /* termination disabled */ 85 set_in.term_pull_up = 0; /* n/a as termination disabled */ 86 set_in.state = 0; /* n/a as configured as an input */ 87 88 ret = rpi_exp_gpio_get_polarity(gc, off); 89 if (ret < 0) 90 return ret; 91 set_in.polarity = ret; /* Retain existing setting */ 92 93 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, 94 &set_in, sizeof(set_in)); 95 if (ret || set_in.gpio != 0) { 96 dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n", 97 off, ret, set_in.gpio); 98 return ret ? ret : -EIO; 99 } 100 return 0; 101 } 102 103 static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val) 104 { 105 struct rpi_exp_gpio *gpio; 106 struct gpio_set_config set_out; 107 int ret; 108 109 gpio = gpiochip_get_data(gc); 110 111 set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 112 set_out.direction = RPI_EXP_GPIO_DIR_OUT; 113 set_out.term_en = 0; /* n/a as an output */ 114 set_out.term_pull_up = 0; /* n/a as termination disabled */ 115 set_out.state = val; /* Output state */ 116 117 ret = rpi_exp_gpio_get_polarity(gc, off); 118 if (ret < 0) 119 return ret; 120 set_out.polarity = ret; /* Retain existing setting */ 121 122 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, 123 &set_out, sizeof(set_out)); 124 if (ret || set_out.gpio != 0) { 125 dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n", 126 off, ret, set_out.gpio); 127 return ret ? ret : -EIO; 128 } 129 return 0; 130 } 131 132 static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off) 133 { 134 struct rpi_exp_gpio *gpio; 135 struct gpio_get_config get; 136 int ret; 137 138 gpio = gpiochip_get_data(gc); 139 140 get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 141 142 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, 143 &get, sizeof(get)); 144 if (ret || get.gpio != 0) { 145 dev_err(gc->parent, 146 "Failed to get GPIO %u config (%d %x)\n", off, ret, 147 get.gpio); 148 return ret ? ret : -EIO; 149 } 150 return !get.direction; 151 } 152 153 static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off) 154 { 155 struct rpi_exp_gpio *gpio; 156 struct gpio_get_set_state get; 157 int ret; 158 159 gpio = gpiochip_get_data(gc); 160 161 get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 162 get.state = 0; /* storage for returned value */ 163 164 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE, 165 &get, sizeof(get)); 166 if (ret || get.gpio != 0) { 167 dev_err(gc->parent, 168 "Failed to get GPIO %u state (%d %x)\n", off, ret, 169 get.gpio); 170 return ret ? ret : -EIO; 171 } 172 return !!get.state; 173 } 174 175 static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val) 176 { 177 struct rpi_exp_gpio *gpio; 178 struct gpio_get_set_state set; 179 int ret; 180 181 gpio = gpiochip_get_data(gc); 182 183 set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ 184 set.state = val; /* Output state */ 185 186 ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE, 187 &set, sizeof(set)); 188 if (ret || set.gpio != 0) 189 dev_err(gc->parent, 190 "Failed to set GPIO %u state (%d %x)\n", off, ret, 191 set.gpio); 192 } 193 194 static int rpi_exp_gpio_probe(struct platform_device *pdev) 195 { 196 struct device *dev = &pdev->dev; 197 struct device_node *np = dev->of_node; 198 struct device_node *fw_node; 199 struct rpi_firmware *fw; 200 struct rpi_exp_gpio *rpi_gpio; 201 202 fw_node = of_get_parent(np); 203 if (!fw_node) { 204 dev_err(dev, "Missing firmware node\n"); 205 return -ENOENT; 206 } 207 208 fw = rpi_firmware_get(fw_node); 209 of_node_put(fw_node); 210 if (!fw) 211 return -EPROBE_DEFER; 212 213 rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL); 214 if (!rpi_gpio) 215 return -ENOMEM; 216 217 rpi_gpio->fw = fw; 218 rpi_gpio->gc.parent = dev; 219 rpi_gpio->gc.label = MODULE_NAME; 220 rpi_gpio->gc.owner = THIS_MODULE; 221 rpi_gpio->gc.of_node = np; 222 rpi_gpio->gc.base = -1; 223 rpi_gpio->gc.ngpio = NUM_GPIO; 224 225 rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in; 226 rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out; 227 rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction; 228 rpi_gpio->gc.get = rpi_exp_gpio_get; 229 rpi_gpio->gc.set = rpi_exp_gpio_set; 230 rpi_gpio->gc.can_sleep = true; 231 232 return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio); 233 } 234 235 static const struct of_device_id rpi_exp_gpio_ids[] = { 236 { .compatible = "raspberrypi,firmware-gpio" }, 237 { } 238 }; 239 MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids); 240 241 static struct platform_driver rpi_exp_gpio_driver = { 242 .driver = { 243 .name = MODULE_NAME, 244 .of_match_table = of_match_ptr(rpi_exp_gpio_ids), 245 }, 246 .probe = rpi_exp_gpio_probe, 247 }; 248 module_platform_driver(rpi_exp_gpio_driver); 249 250 MODULE_LICENSE("GPL"); 251 MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>"); 252 MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver"); 253 MODULE_ALIAS("platform:rpi-exp-gpio"); 254