1 // SPDX-License-Identifier: GPL-2.0-only
2 //
3 // Driver for the regulator based Ethernet Power Sourcing Equipment, without
4 // auto classification support.
5 //
6 // Copyright (c) 2022 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
7 //
8 
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/pse-pd/pse.h>
13 #include <linux/regulator/consumer.h>
14 
15 struct pse_reg_priv {
16 	struct pse_controller_dev pcdev;
17 	struct regulator *ps; /*power source */
18 	enum ethtool_podl_pse_admin_state admin_state;
19 };
20 
21 static struct pse_reg_priv *to_pse_reg(struct pse_controller_dev *pcdev)
22 {
23 	return container_of(pcdev, struct pse_reg_priv, pcdev);
24 }
25 
26 static int
27 pse_reg_ethtool_set_config(struct pse_controller_dev *pcdev, unsigned long id,
28 			   struct netlink_ext_ack *extack,
29 			   const struct pse_control_config *config)
30 {
31 	struct pse_reg_priv *priv = to_pse_reg(pcdev);
32 	int ret;
33 
34 	if (priv->admin_state == config->admin_cotrol)
35 		return 0;
36 
37 	switch (config->admin_cotrol) {
38 	case ETHTOOL_PODL_PSE_ADMIN_STATE_ENABLED:
39 		ret = regulator_enable(priv->ps);
40 		break;
41 	case ETHTOOL_PODL_PSE_ADMIN_STATE_DISABLED:
42 		ret = regulator_disable(priv->ps);
43 		break;
44 	default:
45 		dev_err(pcdev->dev, "Unknown admin state %i\n",
46 			config->admin_cotrol);
47 		ret = -ENOTSUPP;
48 	}
49 
50 	if (ret)
51 		return ret;
52 
53 	priv->admin_state = config->admin_cotrol;
54 
55 	return 0;
56 }
57 
58 static int
59 pse_reg_ethtool_get_status(struct pse_controller_dev *pcdev, unsigned long id,
60 			   struct netlink_ext_ack *extack,
61 			   struct pse_control_status *status)
62 {
63 	struct pse_reg_priv *priv = to_pse_reg(pcdev);
64 	int ret;
65 
66 	ret = regulator_is_enabled(priv->ps);
67 	if (ret < 0)
68 		return ret;
69 
70 	if (!ret)
71 		status->podl_pw_status = ETHTOOL_PODL_PSE_PW_D_STATUS_DISABLED;
72 	else
73 		status->podl_pw_status =
74 			ETHTOOL_PODL_PSE_PW_D_STATUS_DELIVERING;
75 
76 	status->podl_admin_state = priv->admin_state;
77 
78 	return 0;
79 }
80 
81 static const struct pse_controller_ops pse_reg_ops = {
82 	.ethtool_get_status = pse_reg_ethtool_get_status,
83 	.ethtool_set_config = pse_reg_ethtool_set_config,
84 };
85 
86 static int
87 pse_reg_probe(struct platform_device *pdev)
88 {
89 	struct device *dev = &pdev->dev;
90 	struct pse_reg_priv *priv;
91 	int ret;
92 
93 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
94 	if (!priv)
95 		return -ENOMEM;
96 
97 	if (!pdev->dev.of_node)
98 		return -ENOENT;
99 
100 	priv->ps = devm_regulator_get_exclusive(dev, "pse");
101 	if (IS_ERR(priv->ps))
102 		return dev_err_probe(dev, PTR_ERR(priv->ps),
103 				     "failed to get PSE regulator.\n");
104 
105 	platform_set_drvdata(pdev, priv);
106 
107 	ret = regulator_is_enabled(priv->ps);
108 	if (ret < 0)
109 		return ret;
110 
111 	if (ret)
112 		priv->admin_state = ETHTOOL_PODL_PSE_ADMIN_STATE_ENABLED;
113 	else
114 		priv->admin_state = ETHTOOL_PODL_PSE_ADMIN_STATE_DISABLED;
115 
116 	priv->pcdev.owner = THIS_MODULE;
117 	priv->pcdev.ops = &pse_reg_ops;
118 	priv->pcdev.dev = dev;
119 	ret = devm_pse_controller_register(dev, &priv->pcdev);
120 	if (ret) {
121 		dev_err(dev, "failed to register PSE controller (%pe)\n",
122 			ERR_PTR(ret));
123 		return ret;
124 	}
125 
126 	return 0;
127 }
128 
129 static const __maybe_unused struct of_device_id pse_reg_of_match[] = {
130 	{ .compatible = "podl-pse-regulator", },
131 	{ },
132 };
133 MODULE_DEVICE_TABLE(of, pse_reg_of_match);
134 
135 static struct platform_driver pse_reg_driver = {
136 	.probe		= pse_reg_probe,
137 	.driver		= {
138 		.name		= "PSE regulator",
139 		.of_match_table = of_match_ptr(pse_reg_of_match),
140 	},
141 };
142 module_platform_driver(pse_reg_driver);
143 
144 MODULE_AUTHOR("Oleksij Rempel <kernel@pengutronix.de>");
145 MODULE_DESCRIPTION("regulator based Ethernet Power Sourcing Equipment");
146 MODULE_LICENSE("GPL v2");
147 MODULE_ALIAS("platform:pse-regulator");
148