drivers/phy/phy-can-transceiver.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * phy-can-transceiver.c - phy driver for CAN transceivers
   4  *
   5  * Copyright (C) 2021 Texas Instruments Incorporated - https://www.ti.com
   6  *
   7  */
   8 #include <linux/of.h>
   9 #include <linux/phy/phy.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/module.h>
  12 #include <linux/gpio.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/mux/consumer.h>
  15
  16 struct can_transceiver_data {
  17         u32 flags;
  18 #define CAN_TRANSCEIVER_STB_PRESENT     BIT(0)
  19 #define CAN_TRANSCEIVER_EN_PRESENT      BIT(1)
  20 };
  21
  22 struct can_transceiver_phy {
  23         struct phy *generic_phy;
  24         struct gpio_desc *standby_gpio;
  25         struct gpio_desc *enable_gpio;
  26         struct mux_state *mux_state;
  27 };
  28
  29 /* Power on function */
  30 static int can_transceiver_phy_power_on(struct phy *phy)
  31 {
  32         struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);
  33         int ret;
  34
  35         if (can_transceiver_phy->mux_state) {
  36                 ret = mux_state_select(can_transceiver_phy->mux_state);
  37                 if (ret) {
  38                         dev_err(&phy->dev, "Failed to select CAN mux: %d\n", ret);
  39                         return ret;
  40                 }
  41         }
  42         if (can_transceiver_phy->standby_gpio)
  43                 gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 0);
  44         if (can_transceiver_phy->enable_gpio)
  45                 gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 1);
  46
  47         return 0;
  48 }
  49
  50 /* Power off function */
  51 static int can_transceiver_phy_power_off(struct phy *phy)
  52 {
  53         struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);
  54
  55         if (can_transceiver_phy->standby_gpio)
  56                 gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 1);
  57         if (can_transceiver_phy->enable_gpio)
  58                 gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 0);
  59         if (can_transceiver_phy->mux_state)
  60                 mux_state_deselect(can_transceiver_phy->mux_state);
  61
  62         return 0;
  63 }
  64
  65 static const struct phy_ops can_transceiver_phy_ops = {
  66         .power_on       = can_transceiver_phy_power_on,
  67         .power_off      = can_transceiver_phy_power_off,
  68         .owner          = THIS_MODULE,
  69 };
  70
  71 static const struct can_transceiver_data tcan1042_drvdata = {
  72         .flags = CAN_TRANSCEIVER_STB_PRESENT,
  73 };
  74
  75 static const struct can_transceiver_data tcan1043_drvdata = {
  76         .flags = CAN_TRANSCEIVER_STB_PRESENT | CAN_TRANSCEIVER_EN_PRESENT,
  77 };
  78
  79 static const struct of_device_id can_transceiver_phy_ids[] = {
  80         {
  81                 .compatible = "ti,tcan1042",
  82                 .data = &tcan1042_drvdata
  83         },
  84         {
  85                 .compatible = "ti,tcan1043",
  86                 .data = &tcan1043_drvdata
  87         },
  88         {
  89                 .compatible = "nxp,tjr1443",
  90                 .data = &tcan1043_drvdata
  91         },
  92         { }
  93 };
  94 MODULE_DEVICE_TABLE(of, can_transceiver_phy_ids);
  95
  96 static int can_transceiver_phy_probe(struct platform_device *pdev)
  97 {
  98         struct phy_provider *phy_provider;
  99         struct device *dev = &pdev->dev;
 100         struct can_transceiver_phy *can_transceiver_phy;
 101         const struct can_transceiver_data *drvdata;
 102         const struct of_device_id *match;
 103         struct phy *phy;
 104         struct gpio_desc *standby_gpio;
 105         struct gpio_desc *enable_gpio;
 106         u32 max_bitrate = 0;
 107         int err;
 108
 109         can_transceiver_phy = devm_kzalloc(dev, sizeof(struct can_transceiver_phy), GFP_KERNEL);
 110         if (!can_transceiver_phy)
 111                 return -ENOMEM;
 112
 113         match = of_match_node(can_transceiver_phy_ids, pdev->dev.of_node);
 114         drvdata = match->data;
 115
 116         if (of_property_read_bool(dev->of_node, "mux-states")) {
 117                 struct mux_state *mux_state;
 118
 119                 mux_state = devm_mux_state_get(dev, NULL);
 120                 if (IS_ERR(mux_state))
 121                         return dev_err_probe(&pdev->dev, PTR_ERR(mux_state),
 122                                              "failed to get mux\n");
 123                 can_transceiver_phy->mux_state = mux_state;
 124         }
 125
 126         phy = devm_phy_create(dev, dev->of_node,
 127                               &can_transceiver_phy_ops);
 128         if (IS_ERR(phy)) {
 129                 dev_err(dev, "failed to create can transceiver phy\n");
 130                 return PTR_ERR(phy);
 131         }
 132
 133         err = device_property_read_u32(dev, "max-bitrate", &max_bitrate);
 134         if ((err != -EINVAL) && !max_bitrate)
 135                 dev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit\n");
 136         phy->attrs.max_link_rate = max_bitrate;
 137
 138         can_transceiver_phy->generic_phy = phy;
 139
 140         if (drvdata->flags & CAN_TRANSCEIVER_STB_PRESENT) {
 141                 standby_gpio = devm_gpiod_get_optional(dev, "standby", GPIOD_OUT_HIGH);
 142                 if (IS_ERR(standby_gpio))
 143                         return PTR_ERR(standby_gpio);
 144                 can_transceiver_phy->standby_gpio = standby_gpio;
 145         }
 146
 147         if (drvdata->flags & CAN_TRANSCEIVER_EN_PRESENT) {
 148                 enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
 149                 if (IS_ERR(enable_gpio))
 150                         return PTR_ERR(enable_gpio);
 151                 can_transceiver_phy->enable_gpio = enable_gpio;
 152         }
 153
 154         phy_set_drvdata(can_transceiver_phy->generic_phy, can_transceiver_phy);
 155
 156         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 157
 158         return PTR_ERR_OR_ZERO(phy_provider);
 159 }
 160
 161 static struct platform_driver can_transceiver_phy_driver = {
 162         .probe = can_transceiver_phy_probe,
 163         .driver = {
 164                 .name = "can-transceiver-phy",
 165                 .of_match_table = can_transceiver_phy_ids,
 166         },
 167 };
 168
 169 module_platform_driver(can_transceiver_phy_driver);
 170
 171 MODULE_AUTHOR("Faiz Abbas <faiz_abbas@ti.com>");
 172 MODULE_AUTHOR("Aswath Govindraju <a-govindraju@ti.com>");
 173 MODULE_DESCRIPTION("CAN TRANSCEIVER PHY driver");
 174 MODULE_LICENSE("GPL v2");