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