// SPDX-License-Identifier: GPL-2.0
/*
 * phy-can-transceiver.c - phy driver for CAN transceivers
 *
 * Copyright (C) 2021 Texas Instruments Incorporated - https://www.ti.com
 *
 */
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/mux/consumer.h>

struct can_transceiver_data {
 u32 flags;
#define CAN_TRANSCEIVER_STB_PRESENT BIT(0)
#define CAN_TRANSCEIVER_EN_PRESENT BIT(1)
};

struct can_transceiver_phy {
 struct phy *generic_phy;
 struct gpio_desc *standby_gpio;
 struct gpio_desc *enable_gpio;
 struct mux_state *mux_state;
};

/* Power on function */
static int can_transceiver_phy_power_on(struct phy *phy)
{
 struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);
 int ret;

 if (can_transceiver_phy->mux_state) {
  ret = mux_state_select(can_transceiver_phy->mux_state);
  if (ret) {
   dev_err(&phy->dev, "Failed to select CAN mux: %d\n", ret);
   return ret;
  }
 }
 if (can_transceiver_phy->standby_gpio)
  gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 0);
 if (can_transceiver_phy->enable_gpio)
  gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 1);

 return 0;
}

/* Power off function */
static int can_transceiver_phy_power_off(struct phy *phy)
{
 struct can_transceiver_phy *can_transceiver_phy = phy_get_drvdata(phy);

 if (can_transceiver_phy->standby_gpio)
  gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 1);
 if (can_transceiver_phy->enable_gpio)
  gpiod_set_value_cansleep(can_transceiver_phy->enable_gpio, 0);
 if (can_transceiver_phy->mux_state)
  mux_state_deselect(can_transceiver_phy->mux_state);

 return 0;
}

static const struct phy_ops can_transceiver_phy_ops = {
 .power_on = can_transceiver_phy_power_on,
 .power_off = can_transceiver_phy_power_off,
 .owner  = THIS_MODULE,
};

static const struct can_transceiver_data tcan1042_drvdata = {
 .flags = CAN_TRANSCEIVER_STB_PRESENT,
};

static const struct can_transceiver_data tcan1043_drvdata = {
 .flags = CAN_TRANSCEIVER_STB_PRESENT | CAN_TRANSCEIVER_EN_PRESENT,
};

static const struct of_device_id can_transceiver_phy_ids[] = {
 {
  .compatible = "ti,tcan1042",
  .data = &tcan1042_drvdata
 },
 {
  .compatible = "ti,tcan1043",
  .data = &tcan1043_drvdata
 },
 {
  .compatible = "nxp,tjr1443",
  .data = &tcan1043_drvdata
 },
 { }
};
MODULE_DEVICE_TABLE(of, can_transceiver_phy_ids);

/* Temporary wrapper until the multiplexer subsystem supports optional muxes */
static inline struct mux_state *
devm_mux_state_get_optional(struct device *dev, const char *mux_name)
{
 if (!of_property_present(dev->of_node, "mux-states"))
  return NULL;

 return devm_mux_state_get(dev, mux_name);
}

static int can_transceiver_phy_probe(struct platform_device *pdev)
{
 struct phy_provider *phy_provider;
 struct device *dev = &pdev->dev;
 struct can_transceiver_phy *can_transceiver_phy;
 const struct can_transceiver_data *drvdata;
 const struct of_device_id *match;
 struct phy *phy;
 struct gpio_desc *standby_gpio;
 struct gpio_desc *enable_gpio;
 struct mux_state *mux_state;
 u32 max_bitrate = 0;
 int err;

 can_transceiver_phy = devm_kzalloc(dev, sizeof(struct can_transceiver_phy), GFP_KERNEL);
 if (!can_transceiver_phy)
  return -ENOMEM;

 match = of_match_node(can_transceiver_phy_ids, pdev->dev.of_node);
 drvdata = match->data;

 mux_state = devm_mux_state_get_optional(dev, NULL);
 if (IS_ERR(mux_state))
  return PTR_ERR(mux_state);

 can_transceiver_phy->mux_state = mux_state;

 phy = devm_phy_create(dev, dev->of_node,
         &can_transceiver_phy_ops);
 if (IS_ERR(phy)) {
  dev_err(dev, "failed to create can transceiver phy\n");
  return PTR_ERR(phy);
 }

 err = device_property_read_u32(dev, "max-bitrate", &max_bitrate);
 if ((err != -EINVAL) && !max_bitrate)
  dev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit\n");
 phy->attrs.max_link_rate = max_bitrate;

 can_transceiver_phy->generic_phy = phy;

 if (drvdata->flags & CAN_TRANSCEIVER_STB_PRESENT) {
  standby_gpio = devm_gpiod_get_optional(dev, "standby", GPIOD_OUT_HIGH);
  if (IS_ERR(standby_gpio))
   return PTR_ERR(standby_gpio);
  can_transceiver_phy->standby_gpio = standby_gpio;
 }

 if (drvdata->flags & CAN_TRANSCEIVER_EN_PRESENT) {
  enable_gpio = devm_gpiod_get_optional(dev, "enable", GPIOD_OUT_LOW);
  if (IS_ERR(enable_gpio))
   return PTR_ERR(enable_gpio);
  can_transceiver_phy->enable_gpio = enable_gpio;
 }

 phy_set_drvdata(can_transceiver_phy->generic_phy, can_transceiver_phy);

 phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);

 return PTR_ERR_OR_ZERO(phy_provider);
}

static struct platform_driver can_transceiver_phy_driver = {
 .probe = can_transceiver_phy_probe,
 .driver = {
  .name = "can-transceiver-phy",
  .of_match_table = can_transceiver_phy_ids,
 },
};

module_platform_driver(can_transceiver_phy_driver);

MODULE_AUTHOR("Faiz Abbas <faiz_abbas@ti.com>");
MODULE_AUTHOR("Aswath Govindraju <a-govindraju@ti.com>");
MODULE_DESCRIPTION("CAN TRANSCEIVER PHY driver");
MODULE_LICENSE("GPL v2");