1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * GPIO based MDIO bitbang driver. 4 * Supports OpenFirmware. 5 * 6 * Copyright (c) 2008 CSE Semaphore Belgium. 7 * by Laurent Pinchart <laurentp@cse-semaphore.com> 8 * 9 * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt> 10 * 11 * Based on earlier work by 12 * 13 * Copyright (c) 2003 Intracom S.A. 14 * by Pantelis Antoniou <panto@intracom.gr> 15 * 16 * 2005 (c) MontaVista Software, Inc. 17 * Vitaly Bordug <vbordug@ru.mvista.com> 18 */ 19 20 #include <linux/gpio/consumer.h> 21 #include <linux/interrupt.h> 22 #include <linux/mdio-bitbang.h> 23 #include <linux/mdio-gpio.h> 24 #include <linux/module.h> 25 #include <linux/of_mdio.h> 26 #include <linux/platform_data/mdio-gpio.h> 27 #include <linux/platform_device.h> 28 #include <linux/slab.h> 29 30 struct mdio_gpio_info { 31 struct mdiobb_ctrl ctrl; 32 struct gpio_desc *mdc, *mdio, *mdo; 33 }; 34 35 static int mdio_gpio_get_data(struct device *dev, 36 struct mdio_gpio_info *bitbang) 37 { 38 bitbang->mdc = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDC, 39 GPIOD_OUT_LOW); 40 if (IS_ERR(bitbang->mdc)) 41 return PTR_ERR(bitbang->mdc); 42 43 bitbang->mdio = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDIO, 44 GPIOD_IN); 45 if (IS_ERR(bitbang->mdio)) 46 return PTR_ERR(bitbang->mdio); 47 48 bitbang->mdo = devm_gpiod_get_index_optional(dev, NULL, MDIO_GPIO_MDO, 49 GPIOD_OUT_LOW); 50 return PTR_ERR_OR_ZERO(bitbang->mdo); 51 } 52 53 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir) 54 { 55 struct mdio_gpio_info *bitbang = 56 container_of(ctrl, struct mdio_gpio_info, ctrl); 57 58 if (bitbang->mdo) { 59 /* Separate output pin. Always set its value to high 60 * when changing direction. If direction is input, 61 * assume the pin serves as pull-up. If direction is 62 * output, the default value is high. 63 */ 64 gpiod_set_value_cansleep(bitbang->mdo, 1); 65 return; 66 } 67 68 if (dir) 69 gpiod_direction_output(bitbang->mdio, 1); 70 else 71 gpiod_direction_input(bitbang->mdio); 72 } 73 74 static int mdio_get(struct mdiobb_ctrl *ctrl) 75 { 76 struct mdio_gpio_info *bitbang = 77 container_of(ctrl, struct mdio_gpio_info, ctrl); 78 79 return gpiod_get_value_cansleep(bitbang->mdio); 80 } 81 82 static void mdio_set(struct mdiobb_ctrl *ctrl, int what) 83 { 84 struct mdio_gpio_info *bitbang = 85 container_of(ctrl, struct mdio_gpio_info, ctrl); 86 87 if (bitbang->mdo) 88 gpiod_set_value_cansleep(bitbang->mdo, what); 89 else 90 gpiod_set_value_cansleep(bitbang->mdio, what); 91 } 92 93 static void mdc_set(struct mdiobb_ctrl *ctrl, int what) 94 { 95 struct mdio_gpio_info *bitbang = 96 container_of(ctrl, struct mdio_gpio_info, ctrl); 97 98 gpiod_set_value_cansleep(bitbang->mdc, what); 99 } 100 101 static const struct mdiobb_ops mdio_gpio_ops = { 102 .owner = THIS_MODULE, 103 .set_mdc = mdc_set, 104 .set_mdio_dir = mdio_dir, 105 .set_mdio_data = mdio_set, 106 .get_mdio_data = mdio_get, 107 }; 108 109 static struct mii_bus *mdio_gpio_bus_init(struct device *dev, 110 struct mdio_gpio_info *bitbang, 111 int bus_id) 112 { 113 struct mdio_gpio_platform_data *pdata = dev_get_platdata(dev); 114 struct mii_bus *new_bus; 115 116 bitbang->ctrl.ops = &mdio_gpio_ops; 117 118 new_bus = alloc_mdio_bitbang(&bitbang->ctrl); 119 if (!new_bus) 120 return NULL; 121 122 new_bus->name = "GPIO Bitbanged MDIO"; 123 new_bus->parent = dev; 124 125 if (bus_id != -1) 126 snprintf(new_bus->id, sizeof(new_bus->id), "gpio-%x", bus_id); 127 else 128 strscpy(new_bus->id, "gpio", sizeof(new_bus->id)); 129 130 if (pdata) { 131 new_bus->phy_mask = pdata->phy_mask; 132 new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask; 133 } 134 135 if (device_is_compatible(dev, "microchip,mdio-smi0")) { 136 bitbang->ctrl.op_c22_read = 0; 137 bitbang->ctrl.op_c22_write = 0; 138 bitbang->ctrl.override_op_c22 = 1; 139 } 140 141 dev_set_drvdata(dev, new_bus); 142 143 return new_bus; 144 } 145 146 static void mdio_gpio_bus_deinit(struct device *dev) 147 { 148 struct mii_bus *bus = dev_get_drvdata(dev); 149 150 free_mdio_bitbang(bus); 151 } 152 153 static void mdio_gpio_bus_destroy(struct device *dev) 154 { 155 struct mii_bus *bus = dev_get_drvdata(dev); 156 157 mdiobus_unregister(bus); 158 mdio_gpio_bus_deinit(dev); 159 } 160 161 static int mdio_gpio_probe(struct platform_device *pdev) 162 { 163 struct mdio_gpio_info *bitbang; 164 struct mii_bus *new_bus; 165 int ret, bus_id; 166 167 bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL); 168 if (!bitbang) 169 return -ENOMEM; 170 171 ret = mdio_gpio_get_data(&pdev->dev, bitbang); 172 if (ret) 173 return ret; 174 175 if (pdev->dev.of_node) { 176 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio"); 177 if (bus_id < 0) { 178 dev_warn(&pdev->dev, "failed to get alias id\n"); 179 bus_id = 0; 180 } 181 } else { 182 bus_id = pdev->id; 183 } 184 185 new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id); 186 if (!new_bus) 187 return -ENODEV; 188 189 ret = of_mdiobus_register(new_bus, pdev->dev.of_node); 190 if (ret) 191 mdio_gpio_bus_deinit(&pdev->dev); 192 193 return ret; 194 } 195 196 static void mdio_gpio_remove(struct platform_device *pdev) 197 { 198 mdio_gpio_bus_destroy(&pdev->dev); 199 } 200 201 static const struct of_device_id mdio_gpio_of_match[] = { 202 { .compatible = "virtual,mdio-gpio", }, 203 { .compatible = "microchip,mdio-smi0" }, 204 { /* sentinel */ } 205 }; 206 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match); 207 208 static struct platform_driver mdio_gpio_driver = { 209 .probe = mdio_gpio_probe, 210 .remove_new = mdio_gpio_remove, 211 .driver = { 212 .name = "mdio-gpio", 213 .of_match_table = mdio_gpio_of_match, 214 }, 215 }; 216 217 module_platform_driver(mdio_gpio_driver); 218 219 MODULE_ALIAS("platform:mdio-gpio"); 220 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas"); 221 MODULE_LICENSE("GPL v2"); 222 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO"); 223