1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2022 Google LLC
4  *
5  * This driver provides the ability to configure Type-C muxes and retimers which are controlled by
6  * the ChromeOS EC.
7  */
8 
9 #include <linux/acpi.h>
10 #include <linux/delay.h>
11 #include <linux/jiffies.h>
12 #include <linux/module.h>
13 #include <linux/platform_data/cros_ec_commands.h>
14 #include <linux/platform_data/cros_ec_proto.h>
15 #include <linux/platform_device.h>
16 #include <linux/usb/typec_altmode.h>
17 #include <linux/usb/typec_dp.h>
18 #include <linux/usb/typec_mux.h>
19 #include <linux/usb/typec_retimer.h>
20 
21 /* Handles and other relevant data required for each port's switches. */
22 struct cros_typec_port {
23 	int port_num;
24 	struct typec_mux_dev *mode_switch;
25 	struct typec_retimer *retimer;
26 	struct cros_typec_switch_data *sdata;
27 };
28 
29 /* Driver-specific data. */
30 struct cros_typec_switch_data {
31 	struct device *dev;
32 	struct cros_ec_device *ec;
33 	struct cros_typec_port *ports[EC_USB_PD_MAX_PORTS];
34 };
35 
cros_typec_cmd_mux_set(struct cros_typec_switch_data * sdata,int port_num,u8 index,u8 state)36 static int cros_typec_cmd_mux_set(struct cros_typec_switch_data *sdata, int port_num, u8 index,
37 				  u8 state)
38 {
39 	struct ec_params_typec_control req = {
40 		.port = port_num,
41 		.command = TYPEC_CONTROL_COMMAND_USB_MUX_SET,
42 		.mux_params = {
43 			.mux_index = index,
44 			.mux_flags = state,
45 		},
46 	};
47 
48 	return cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req, sizeof(req), NULL, 0);
49 }
50 
cros_typec_get_mux_state(unsigned long mode,struct typec_altmode * alt)51 static int cros_typec_get_mux_state(unsigned long mode, struct typec_altmode *alt)
52 {
53 	int ret = -EOPNOTSUPP;
54 	u8 pin_assign;
55 
56 	if (mode == TYPEC_STATE_SAFE) {
57 		ret = USB_PD_MUX_SAFE_MODE;
58 	} else if (mode == TYPEC_STATE_USB) {
59 		ret = USB_PD_MUX_USB_ENABLED;
60 	} else if (alt && alt->svid == USB_TYPEC_DP_SID) {
61 		ret = USB_PD_MUX_DP_ENABLED;
62 		pin_assign = mode - TYPEC_STATE_MODAL;
63 		if (pin_assign & DP_PIN_ASSIGN_D)
64 			ret |= USB_PD_MUX_USB_ENABLED;
65 	}
66 
67 	return ret;
68 }
69 
cros_typec_send_clear_event(struct cros_typec_switch_data * sdata,int port_num,u32 events_mask)70 static int cros_typec_send_clear_event(struct cros_typec_switch_data *sdata, int port_num,
71 				       u32 events_mask)
72 {
73 	struct ec_params_typec_control req = {
74 		.port = port_num,
75 		.command = TYPEC_CONTROL_COMMAND_CLEAR_EVENTS,
76 		.clear_events_mask = events_mask,
77 	};
78 
79 	return cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_CONTROL, &req, sizeof(req), NULL, 0);
80 }
81 
cros_typec_check_event(struct cros_typec_switch_data * sdata,int port_num,u32 mask)82 static bool cros_typec_check_event(struct cros_typec_switch_data *sdata, int port_num, u32 mask)
83 {
84 	struct ec_response_typec_status resp;
85 	struct ec_params_typec_status req = {
86 		.port = port_num,
87 	};
88 	int ret;
89 
90 	ret = cros_ec_cmd(sdata->ec, 0, EC_CMD_TYPEC_STATUS, &req, sizeof(req),
91 			  &resp, sizeof(resp));
92 	if (ret < 0) {
93 		dev_warn(sdata->dev, "EC_CMD_TYPEC_STATUS failed for port: %d\n", port_num);
94 		return false;
95 	}
96 
97 	if (resp.events & mask)
98 		return true;
99 
100 	return false;
101 }
102 
103 /*
104  * The ChromeOS EC treats both mode-switches and retimers as "muxes" for the purposes of the
105  * host command API. This common function configures and verifies the retimer/mode-switch
106  * according to the provided setting.
107  */
cros_typec_configure_mux(struct cros_typec_switch_data * sdata,int port_num,int index,unsigned long mode,struct typec_altmode * alt)108 static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
109 				    unsigned long mode, struct typec_altmode *alt)
110 {
111 	unsigned long end;
112 	u32 event_mask;
113 	u8 mux_state;
114 	int ret;
115 
116 	ret = cros_typec_get_mux_state(mode, alt);
117 	if (ret < 0)
118 		return ret;
119 	mux_state = (u8)ret;
120 
121 	/* Clear any old mux set done event. */
122 	if (index == 0)
123 		event_mask = PD_STATUS_EVENT_MUX_0_SET_DONE;
124 	else
125 		event_mask = PD_STATUS_EVENT_MUX_1_SET_DONE;
126 
127 	ret = cros_typec_send_clear_event(sdata, port_num, event_mask);
128 	if (ret < 0)
129 		return ret;
130 
131 	/* Send the set command. */
132 	ret = cros_typec_cmd_mux_set(sdata, port_num, index, mux_state);
133 	if (ret < 0)
134 		return ret;
135 
136 	/* Check for the mux set done event. */
137 	end = jiffies + msecs_to_jiffies(1000);
138 	do {
139 		if (cros_typec_check_event(sdata, port_num, event_mask))
140 			return 0;
141 
142 		usleep_range(500, 1000);
143 	} while (time_before(jiffies, end));
144 
145 	dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
146 		index, mux_state);
147 
148 	return -ETIMEDOUT;
149 }
150 
cros_typec_mode_switch_set(struct typec_mux_dev * mode_switch,struct typec_mux_state * state)151 static int cros_typec_mode_switch_set(struct typec_mux_dev *mode_switch,
152 				      struct typec_mux_state *state)
153 {
154 	struct cros_typec_port *port = typec_mux_get_drvdata(mode_switch);
155 
156 	/* Mode switches have index 0. */
157 	return cros_typec_configure_mux(port->sdata, port->port_num, 0, state->mode, state->alt);
158 }
159 
cros_typec_retimer_set(struct typec_retimer * retimer,struct typec_retimer_state * state)160 static int cros_typec_retimer_set(struct typec_retimer *retimer, struct typec_retimer_state *state)
161 {
162 	struct cros_typec_port *port = typec_retimer_get_drvdata(retimer);
163 
164 	/* Retimers have index 1. */
165 	return cros_typec_configure_mux(port->sdata, port->port_num, 1, state->mode, state->alt);
166 }
167 
cros_typec_unregister_switches(struct cros_typec_switch_data * sdata)168 static void cros_typec_unregister_switches(struct cros_typec_switch_data *sdata)
169 {
170 	int i;
171 
172 	for (i = 0; i < EC_USB_PD_MAX_PORTS; i++) {
173 		if (!sdata->ports[i])
174 			continue;
175 		typec_retimer_unregister(sdata->ports[i]->retimer);
176 		typec_mux_unregister(sdata->ports[i]->mode_switch);
177 	}
178 }
179 
cros_typec_register_mode_switch(struct cros_typec_port * port,struct fwnode_handle * fwnode)180 static int cros_typec_register_mode_switch(struct cros_typec_port *port,
181 					   struct fwnode_handle *fwnode)
182 {
183 	struct typec_mux_desc mode_switch_desc = {
184 		.fwnode = fwnode,
185 		.drvdata = port,
186 		.name = fwnode_get_name(fwnode),
187 		.set = cros_typec_mode_switch_set,
188 	};
189 
190 	port->mode_switch = typec_mux_register(port->sdata->dev, &mode_switch_desc);
191 
192 	return PTR_ERR_OR_ZERO(port->mode_switch);
193 }
194 
cros_typec_register_retimer(struct cros_typec_port * port,struct fwnode_handle * fwnode)195 static int cros_typec_register_retimer(struct cros_typec_port *port, struct fwnode_handle *fwnode)
196 {
197 	struct typec_retimer_desc retimer_desc = {
198 		.fwnode = fwnode,
199 		.drvdata = port,
200 		.name = fwnode_get_name(fwnode),
201 		.set = cros_typec_retimer_set,
202 	};
203 
204 	port->retimer = typec_retimer_register(port->sdata->dev, &retimer_desc);
205 
206 	return PTR_ERR_OR_ZERO(port->retimer);
207 }
208 
cros_typec_register_switches(struct cros_typec_switch_data * sdata)209 static int cros_typec_register_switches(struct cros_typec_switch_data *sdata)
210 {
211 	struct cros_typec_port *port;
212 	struct device *dev = sdata->dev;
213 	struct fwnode_handle *fwnode;
214 	struct acpi_device *adev;
215 	unsigned long long index;
216 	int nports, ret;
217 
218 	nports = device_get_child_node_count(dev);
219 	if (nports == 0) {
220 		dev_err(dev, "No switch devices found.\n");
221 		return -ENODEV;
222 	}
223 
224 	device_for_each_child_node(dev, fwnode) {
225 		port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
226 		if (!port) {
227 			ret = -ENOMEM;
228 			goto err_switch;
229 		}
230 
231 		adev = to_acpi_device_node(fwnode);
232 		if (!adev) {
233 			dev_err(fwnode->dev, "Couldn't get ACPI device handle\n");
234 			ret = -ENODEV;
235 			goto err_switch;
236 		}
237 
238 		ret = acpi_evaluate_integer(adev->handle, "_ADR", NULL, &index);
239 		if (ACPI_FAILURE(ret)) {
240 			dev_err(fwnode->dev, "_ADR wasn't evaluated\n");
241 			ret = -ENODATA;
242 			goto err_switch;
243 		}
244 
245 		if (index >= EC_USB_PD_MAX_PORTS) {
246 			dev_err(fwnode->dev, "Invalid port index number: %llu\n", index);
247 			ret = -EINVAL;
248 			goto err_switch;
249 		}
250 		port->sdata = sdata;
251 		port->port_num = index;
252 		sdata->ports[index] = port;
253 
254 		if (fwnode_property_present(fwnode, "retimer-switch")) {
255 			ret = cros_typec_register_retimer(port, fwnode);
256 			if (ret) {
257 				dev_err(dev, "Retimer switch register failed\n");
258 				goto err_switch;
259 			}
260 
261 			dev_dbg(dev, "Retimer switch registered for index %llu\n", index);
262 		}
263 
264 		if (!fwnode_property_present(fwnode, "mode-switch"))
265 			continue;
266 
267 		ret = cros_typec_register_mode_switch(port, fwnode);
268 		if (ret) {
269 			dev_err(dev, "Mode switch register failed\n");
270 			goto err_switch;
271 		}
272 
273 		dev_dbg(dev, "Mode switch registered for index %llu\n", index);
274 	}
275 
276 	return 0;
277 err_switch:
278 	fwnode_handle_put(fwnode);
279 	cros_typec_unregister_switches(sdata);
280 	return ret;
281 }
282 
cros_typec_switch_probe(struct platform_device * pdev)283 static int cros_typec_switch_probe(struct platform_device *pdev)
284 {
285 	struct device *dev = &pdev->dev;
286 	struct cros_typec_switch_data *sdata;
287 
288 	sdata = devm_kzalloc(dev, sizeof(*sdata), GFP_KERNEL);
289 	if (!sdata)
290 		return -ENOMEM;
291 
292 	sdata->dev = dev;
293 	sdata->ec = dev_get_drvdata(pdev->dev.parent);
294 
295 	platform_set_drvdata(pdev, sdata);
296 
297 	return cros_typec_register_switches(sdata);
298 }
299 
cros_typec_switch_remove(struct platform_device * pdev)300 static void cros_typec_switch_remove(struct platform_device *pdev)
301 {
302 	struct cros_typec_switch_data *sdata = platform_get_drvdata(pdev);
303 
304 	cros_typec_unregister_switches(sdata);
305 }
306 
307 #ifdef CONFIG_ACPI
308 static const struct acpi_device_id cros_typec_switch_acpi_id[] = {
309 	{ "GOOG001A", 0 },
310 	{}
311 };
312 MODULE_DEVICE_TABLE(acpi, cros_typec_switch_acpi_id);
313 #endif
314 
315 static struct platform_driver cros_typec_switch_driver = {
316 	.driver	= {
317 		.name = "cros-typec-switch",
318 		.acpi_match_table = ACPI_PTR(cros_typec_switch_acpi_id),
319 	},
320 	.probe = cros_typec_switch_probe,
321 	.remove_new = cros_typec_switch_remove,
322 };
323 
324 module_platform_driver(cros_typec_switch_driver);
325 
326 MODULE_AUTHOR("Prashant Malani <pmalani@chromium.org>");
327 MODULE_DESCRIPTION("ChromeOS EC Type-C Switch control");
328 MODULE_LICENSE("GPL");
329