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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 | // SPDX-License-Identifier: GPL-2.0+ /* * Raspberry Pi 3 expander GPIO driver * * Uses the firmware mailbox service to communicate with the * GPIO expander on the VPU. * * Copyright (C) 2017 Raspberry Pi Trading Ltd. */ #include <linux/err.h> #include <linux/gpio/driver.h> #include <linux/module.h> #include <linux/platform_device.h> #include <soc/bcm2835/raspberrypi-firmware.h> #define MODULE_NAME "raspberrypi-exp-gpio" #define NUM_GPIO 8 #define RPI_EXP_GPIO_BASE 128 #define RPI_EXP_GPIO_DIR_IN 0 #define RPI_EXP_GPIO_DIR_OUT 1 struct rpi_exp_gpio { struct gpio_chip gc; struct rpi_firmware *fw; }; /* VC4 firmware mailbox interface data structures */ struct gpio_set_config { u32 gpio; u32 direction; u32 polarity; u32 term_en; u32 term_pull_up; u32 state; }; struct gpio_get_config { u32 gpio; u32 direction; u32 polarity; u32 term_en; u32 term_pull_up; }; struct gpio_get_set_state { u32 gpio; u32 state; }; static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_config get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } return get.polarity; } static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_set_config set_in; int ret; gpio = gpiochip_get_data(gc); set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set_in.direction = RPI_EXP_GPIO_DIR_IN; set_in.term_en = 0; /* termination disabled */ set_in.term_pull_up = 0; /* n/a as termination disabled */ set_in.state = 0; /* n/a as configured as an input */ ret = rpi_exp_gpio_get_polarity(gc, off); if (ret < 0) return ret; set_in.polarity = ret; /* Retain existing setting */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, &set_in, sizeof(set_in)); if (ret || set_in.gpio != 0) { dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n", off, ret, set_in.gpio); return ret ? ret : -EIO; } return 0; } static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val) { struct rpi_exp_gpio *gpio; struct gpio_set_config set_out; int ret; gpio = gpiochip_get_data(gc); set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set_out.direction = RPI_EXP_GPIO_DIR_OUT; set_out.term_en = 0; /* n/a as an output */ set_out.term_pull_up = 0; /* n/a as termination disabled */ set_out.state = val; /* Output state */ ret = rpi_exp_gpio_get_polarity(gc, off); if (ret < 0) return ret; set_out.polarity = ret; /* Retain existing setting */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, &set_out, sizeof(set_out)); if (ret || set_out.gpio != 0) { dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n", off, ret, set_out.gpio); return ret ? ret : -EIO; } return 0; } static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_config get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } if (get.direction) return GPIO_LINE_DIRECTION_OUT; return GPIO_LINE_DIRECTION_IN; } static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off) { struct rpi_exp_gpio *gpio; struct gpio_get_set_state get; int ret; gpio = gpiochip_get_data(gc); get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ get.state = 0; /* storage for returned value */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE, &get, sizeof(get)); if (ret || get.gpio != 0) { dev_err(gc->parent, "Failed to get GPIO %u state (%d %x)\n", off, ret, get.gpio); return ret ? ret : -EIO; } return !!get.state; } static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val) { struct rpi_exp_gpio *gpio; struct gpio_get_set_state set; int ret; gpio = gpiochip_get_data(gc); set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ set.state = val; /* Output state */ ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE, &set, sizeof(set)); if (ret || set.gpio != 0) dev_err(gc->parent, "Failed to set GPIO %u state (%d %x)\n", off, ret, set.gpio); } static int rpi_exp_gpio_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct device_node *fw_node; struct rpi_firmware *fw; struct rpi_exp_gpio *rpi_gpio; fw_node = of_get_parent(np); if (!fw_node) { dev_err(dev, "Missing firmware node\n"); return -ENOENT; } fw = devm_rpi_firmware_get(&pdev->dev, fw_node); of_node_put(fw_node); if (!fw) return -EPROBE_DEFER; rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL); if (!rpi_gpio) return -ENOMEM; rpi_gpio->fw = fw; rpi_gpio->gc.parent = dev; rpi_gpio->gc.label = MODULE_NAME; rpi_gpio->gc.owner = THIS_MODULE; rpi_gpio->gc.base = -1; rpi_gpio->gc.ngpio = NUM_GPIO; rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in; rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out; rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction; rpi_gpio->gc.get = rpi_exp_gpio_get; rpi_gpio->gc.set = rpi_exp_gpio_set; rpi_gpio->gc.can_sleep = true; return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio); } static const struct of_device_id rpi_exp_gpio_ids[] = { { .compatible = "raspberrypi,firmware-gpio" }, { } }; MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids); static struct platform_driver rpi_exp_gpio_driver = { .driver = { .name = MODULE_NAME, .of_match_table = rpi_exp_gpio_ids, }, .probe = rpi_exp_gpio_probe, }; module_platform_driver(rpi_exp_gpio_driver); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>"); MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver"); MODULE_ALIAS("platform:rpi-exp-gpio"); |