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");
175