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/phy/phy.h>
   9 #include<linux/platform_device.h>
  10 #include<linux/module.h>
  11 #include<linux/gpio.h>
  12 #include<linux/gpio/consumer.h>
  13
  14 struct can_transceiver_data {
  15         u32 flags;
  16 #define CAN_TRANSCEIVER_STB_PRESENT     BIT(0)
  17 #define CAN_TRANSCEIVER_EN_PRESENT      BIT(1)
  18 };
  19
  20 struct can_transceiver_phy {
  21         struct phy *generic_phy;
  22         struct gpio_desc *standby_gpio;
  23         struct gpio_desc *enable_gpio;
  24 };
  25
  26 /* Power on function */
  27 static int can_transceiver_phy_power_on(struct phy *phy)
  28 {
  29         struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);
  30
  31         if (can_transceiver_phy->standby_gpio)
  32                 gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 0);
  33         if (can_transceiver_phy->enable_gpio)
  34                 gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 1);
  35
  36         return 0;
  37 }
  38
  39 /* Power off function */
  40 static int can_transceiver_phy_power_off(struct phy *phy)
  41 {
  42         struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);
  43
  44         if (can_transceiver_phy->standby_gpio)
  45                 gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 1);
  46         if (can_transceiver_phy->enable_gpio)
  47                 gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 0);
  48
  49         return 0;
  50 }
  51
  52 static const struct phy_ops can_transceiver_phy_ops = {
  53         .power_on       = can_transceiver_phy_power_on,
  54         .power_off      = can_transceiver_phy_power_off,
  55         .owner          = THIS_MODULE,
  56 };
  57
  58 static const struct can_transceiver_data tcan1042_drvdata = {
  59         .flags = CAN_TRANSCEIVER_STB_PRESENT,
  60 };
  61
  62 static const struct can_transceiver_data tcan1043_drvdata = {
  63         .flags = CAN_TRANSCEIVER_STB_PRESENT | CAN_TRANSCEIVER_EN_PRESENT,
  64 };
  65
  66 static const struct of_device_id can_transceiver_phy_ids[] = {
  67         {
  68                 .compatible = "ti,tcan1042",
  69                 .data = &tcan1042_drvdata
  70         },
  71         {
  72                 .compatible = "ti,tcan1043",
  73                 .data = &tcan1043_drvdata
  74         },
  75         { }
  76 };
  77 MODULE_DEVICE_TABLE(of, can_transceiver_phy_ids);
  78
  79 static int can_transceiver_phy_probe(struct platform_device *pdev)
  80 {
  81         struct phy_provider *phy_provider;
  82         struct device *dev = &pdev->dev;
  83         struct can_transceiver_phy *can_transceiver_phy;
  84         const struct can_transceiver_data *drvdata;
  85         const struct of_device_id *match;
  86         struct phy *phy;
  87         struct gpio_desc *standby_gpio;
  88         struct gpio_desc *enable_gpio;
  89         u32 max_bitrate = 0;
  90
  91         can_transceiver_phy = devm_kzalloc(dev, sizeof(struct can_transceiver_phy), GFP_KERNEL);
  92         if (!can_transceiver_phy)
  93                 return -ENOMEM;
  94
  95         match = of_match_node(can_transceiver_phy_ids, pdev->dev.of_node);
  96         drvdata = match->data;
  97
  98         phy = devm_phy_create(dev, dev->of_node,
  99                               &can_transceiver_phy_ops);
 100         if (IS_ERR(phy)) {
 101                 dev_err(dev, "failed to create can transceiver phy\n");
 102                 return PTR_ERR(phy);
 103         }
 104
 105         device_property_read_u32(dev, "max-bitrate", &max_bitrate);
 106         if (!max_bitrate)
 107                 dev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit\n");
 108         phy->attrs.max_link_rate = max_bitrate;
 109
 110         can_transceiver_phy->generic_phy = phy;
 111
 112         if (drvdata->flags & CAN_TRANSCEIVER_STB_PRESENT) {
 113                 standby_gpio = devm_gpiod_get(dev, "standby", GPIOD_OUT_HIGH);
 114                 if (IS_ERR(standby_gpio))
 115                         return PTR_ERR(standby_gpio);
 116                 can_transceiver_phy->standby_gpio = standby_gpio;
 117         }
 118
 119         if (drvdata->flags & CAN_TRANSCEIVER_EN_PRESENT) {
 120                 enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
 121                 if (IS_ERR(enable_gpio))
 122                         return PTR_ERR(enable_gpio);
 123                 can_transceiver_phy->enable_gpio = enable_gpio;
 124         }
 125
 126         phy_set_drvdata(can_transceiver_phy->generic_phy, can_transceiver_phy);
 127
 128         phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 129
 130         return PTR_ERR_OR_ZERO(phy_provider);
 131 }
 132
 133 static struct platform_driver can_transceiver_phy_driver = {
 134         .probe = can_transceiver_phy_probe,
 135         .driver = {
 136                 .name = "can-transceiver-phy",
 137                 .of_match_table = can_transceiver_phy_ids,
 138         },
 139 };
 140
 141 module_platform_driver(can_transceiver_phy_driver);
 142
 143 MODULE_AUTHOR("Faiz Abbas <[email protected]>");
 144 MODULE_AUTHOR("Aswath Govindraju <[email protected]>");
 145 MODULE_DESCRIPTION("CAN TRANSCEIVER PHY driver");
 146 MODULE_LICENSE("GPL v2");