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
16 struct can_transceiver_data {
17 u32 flags;
18 #define CAN_TRANSCEIVER_STB_PRESENT BIT(0)
19 #define CAN_TRANSCEIVER_EN_PRESENT BIT(1)
20 };
21
22 struct 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 */
can_transceiver_phy_power_on(struct phy * phy)30 static 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 */
can_transceiver_phy_power_off(struct phy * phy)51 static 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
65 static 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
71 static const struct can_transceiver_data tcan1042_drvdata = {
72 .flags = CAN_TRANSCEIVER_STB_PRESENT,
73 };
74
75 static const struct can_transceiver_data tcan1043_drvdata = {
76 .flags = CAN_TRANSCEIVER_STB_PRESENT | CAN_TRANSCEIVER_EN_PRESENT,
77 };
78
79 static 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 };
94 MODULE_DEVICE_TABLE(of, can_transceiver_phy_ids);
95
can_transceiver_phy_probe(struct platform_device * pdev)96 static 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
161 static 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
169 module_platform_driver(can_transceiver_phy_driver);
170
171 MODULE_AUTHOR("Faiz Abbas <faiz_abbas@ti.com>");
172 MODULE_AUTHOR("Aswath Govindraju <a-govindraju@ti.com>");
173 MODULE_DESCRIPTION("CAN TRANSCEIVER PHY driver");
174 MODULE_LICENSE("GPL v2");
175