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
 16struct can_transceiver_data {
 17	u32 flags;
 18#define CAN_TRANSCEIVER_STB_PRESENT	BIT(0)
 19#define CAN_TRANSCEIVER_EN_PRESENT	BIT(1)
 20};
 21
 22struct 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 */
 30static 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 */
 51static 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
 65static 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
 71static const struct can_transceiver_data tcan1042_drvdata = {
 72	.flags = CAN_TRANSCEIVER_STB_PRESENT,
 73};
 74
 75static const struct can_transceiver_data tcan1043_drvdata = {
 76	.flags = CAN_TRANSCEIVER_STB_PRESENT | CAN_TRANSCEIVER_EN_PRESENT,
 77};
 78
 79static 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};
 94MODULE_DEVICE_TABLE(of, can_transceiver_phy_ids);
 95
 96static 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
161static 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
169module_platform_driver(can_transceiver_phy_driver);
170
171MODULE_AUTHOR("Faiz Abbas <faiz_abbas@ti.com>");
172MODULE_AUTHOR("Aswath Govindraju <a-govindraju@ti.com>");
173MODULE_DESCRIPTION("CAN TRANSCEIVER PHY driver");
174MODULE_LICENSE("GPL v2");