xref: /linux/drivers/gpu/drm/amd/amdgpu/amdgpu_i2c.c (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e)
1 /*
2  * Copyright 2007-8 Advanced Micro Devices, Inc.
3  * Copyright 2008 Red Hat Inc.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice shall be included in
13  * all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21  * OTHER DEALINGS IN THE SOFTWARE.
22  *
23  * Authors: Dave Airlie
24  *          Alex Deucher
25  */
26 
27 #include <linux/export.h>
28 #include <linux/pci.h>
29 
30 #include <drm/drm_edid.h>
31 #include <drm/amdgpu_drm.h>
32 #include "amdgpu.h"
33 #include "amdgpu_i2c.h"
34 #include "amdgpu_atombios.h"
35 #include "atom.h"
36 #include "atombios_dp.h"
37 #include "atombios_i2c.h"
38 
39 /* bit banging i2c */
40 static int amdgpu_i2c_pre_xfer(struct i2c_adapter *i2c_adap)
41 {
42 	struct amdgpu_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
43 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
44 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
45 	uint32_t temp;
46 
47 	mutex_lock(&i2c->mutex);
48 
49 	/* switch the pads to ddc mode */
50 	if (rec->hw_capable) {
51 		temp = RREG32(rec->mask_clk_reg);
52 		temp &= ~(1 << 16);
53 		WREG32(rec->mask_clk_reg, temp);
54 	}
55 
56 	/* clear the output pin values */
57 	temp = RREG32(rec->a_clk_reg) & ~rec->a_clk_mask;
58 	WREG32(rec->a_clk_reg, temp);
59 
60 	temp = RREG32(rec->a_data_reg) & ~rec->a_data_mask;
61 	WREG32(rec->a_data_reg, temp);
62 
63 	/* set the pins to input */
64 	temp = RREG32(rec->en_clk_reg) & ~rec->en_clk_mask;
65 	WREG32(rec->en_clk_reg, temp);
66 
67 	temp = RREG32(rec->en_data_reg) & ~rec->en_data_mask;
68 	WREG32(rec->en_data_reg, temp);
69 
70 	/* mask the gpio pins for software use */
71 	temp = RREG32(rec->mask_clk_reg) | rec->mask_clk_mask;
72 	WREG32(rec->mask_clk_reg, temp);
73 	temp = RREG32(rec->mask_clk_reg);
74 
75 	temp = RREG32(rec->mask_data_reg) | rec->mask_data_mask;
76 	WREG32(rec->mask_data_reg, temp);
77 	temp = RREG32(rec->mask_data_reg);
78 
79 	return 0;
80 }
81 
82 static void amdgpu_i2c_post_xfer(struct i2c_adapter *i2c_adap)
83 {
84 	struct amdgpu_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
85 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
86 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
87 	uint32_t temp;
88 
89 	/* unmask the gpio pins for software use */
90 	temp = RREG32(rec->mask_clk_reg) & ~rec->mask_clk_mask;
91 	WREG32(rec->mask_clk_reg, temp);
92 	temp = RREG32(rec->mask_clk_reg);
93 
94 	temp = RREG32(rec->mask_data_reg) & ~rec->mask_data_mask;
95 	WREG32(rec->mask_data_reg, temp);
96 	temp = RREG32(rec->mask_data_reg);
97 
98 	mutex_unlock(&i2c->mutex);
99 }
100 
101 static int amdgpu_i2c_get_clock(void *i2c_priv)
102 {
103 	struct amdgpu_i2c_chan *i2c = i2c_priv;
104 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
105 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
106 	uint32_t val;
107 
108 	/* read the value off the pin */
109 	val = RREG32(rec->y_clk_reg);
110 	val &= rec->y_clk_mask;
111 
112 	return (val != 0);
113 }
114 
115 
116 static int amdgpu_i2c_get_data(void *i2c_priv)
117 {
118 	struct amdgpu_i2c_chan *i2c = i2c_priv;
119 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
120 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
121 	uint32_t val;
122 
123 	/* read the value off the pin */
124 	val = RREG32(rec->y_data_reg);
125 	val &= rec->y_data_mask;
126 
127 	return (val != 0);
128 }
129 
130 static void amdgpu_i2c_set_clock(void *i2c_priv, int clock)
131 {
132 	struct amdgpu_i2c_chan *i2c = i2c_priv;
133 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
134 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
135 	uint32_t val;
136 
137 	/* set pin direction */
138 	val = RREG32(rec->en_clk_reg) & ~rec->en_clk_mask;
139 	val |= clock ? 0 : rec->en_clk_mask;
140 	WREG32(rec->en_clk_reg, val);
141 }
142 
143 static void amdgpu_i2c_set_data(void *i2c_priv, int data)
144 {
145 	struct amdgpu_i2c_chan *i2c = i2c_priv;
146 	struct amdgpu_device *adev = drm_to_adev(i2c->dev);
147 	struct amdgpu_i2c_bus_rec *rec = &i2c->rec;
148 	uint32_t val;
149 
150 	/* set pin direction */
151 	val = RREG32(rec->en_data_reg) & ~rec->en_data_mask;
152 	val |= data ? 0 : rec->en_data_mask;
153 	WREG32(rec->en_data_reg, val);
154 }
155 
156 static const struct i2c_algorithm amdgpu_atombios_i2c_algo = {
157 	.master_xfer = amdgpu_atombios_i2c_xfer,
158 	.functionality = amdgpu_atombios_i2c_func,
159 };
160 
161 struct amdgpu_i2c_chan *amdgpu_i2c_create(struct drm_device *dev,
162 					  const struct amdgpu_i2c_bus_rec *rec,
163 					  const char *name)
164 {
165 	struct amdgpu_i2c_chan *i2c;
166 	int ret;
167 
168 	/* don't add the mm_i2c bus unless hw_i2c is enabled */
169 	if (rec->mm_i2c && (amdgpu_hw_i2c == 0))
170 		return NULL;
171 
172 	i2c = kzalloc(sizeof(struct amdgpu_i2c_chan), GFP_KERNEL);
173 	if (i2c == NULL)
174 		return NULL;
175 
176 	i2c->rec = *rec;
177 	i2c->adapter.owner = THIS_MODULE;
178 	i2c->adapter.class = I2C_CLASS_DDC;
179 	i2c->adapter.dev.parent = dev->dev;
180 	i2c->dev = dev;
181 	i2c_set_adapdata(&i2c->adapter, i2c);
182 	mutex_init(&i2c->mutex);
183 	if (rec->hw_capable &&
184 	    amdgpu_hw_i2c) {
185 		/* hw i2c using atom */
186 		snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
187 			 "AMDGPU i2c hw bus %s", name);
188 		i2c->adapter.algo = &amdgpu_atombios_i2c_algo;
189 		ret = i2c_add_adapter(&i2c->adapter);
190 		if (ret)
191 			goto out_free;
192 	} else {
193 		/* set the amdgpu bit adapter */
194 		snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
195 			 "AMDGPU i2c bit bus %s", name);
196 		i2c->adapter.algo_data = &i2c->bit;
197 		i2c->bit.pre_xfer = amdgpu_i2c_pre_xfer;
198 		i2c->bit.post_xfer = amdgpu_i2c_post_xfer;
199 		i2c->bit.setsda = amdgpu_i2c_set_data;
200 		i2c->bit.setscl = amdgpu_i2c_set_clock;
201 		i2c->bit.getsda = amdgpu_i2c_get_data;
202 		i2c->bit.getscl = amdgpu_i2c_get_clock;
203 		i2c->bit.udelay = 10;
204 		i2c->bit.timeout = usecs_to_jiffies(2200);	/* from VESA */
205 		i2c->bit.data = i2c;
206 		ret = i2c_bit_add_bus(&i2c->adapter);
207 		if (ret) {
208 			DRM_ERROR("Failed to register bit i2c %s\n", name);
209 			goto out_free;
210 		}
211 	}
212 
213 	return i2c;
214 out_free:
215 	kfree(i2c);
216 	return NULL;
217 
218 }
219 
220 void amdgpu_i2c_destroy(struct amdgpu_i2c_chan *i2c)
221 {
222 	if (!i2c)
223 		return;
224 	WARN_ON(i2c->has_aux);
225 	i2c_del_adapter(&i2c->adapter);
226 	kfree(i2c);
227 }
228 
229 /* Add the default buses */
230 void amdgpu_i2c_init(struct amdgpu_device *adev)
231 {
232 	if (amdgpu_hw_i2c)
233 		DRM_INFO("hw_i2c forced on, you may experience display detection problems!\n");
234 
235 	amdgpu_atombios_i2c_init(adev);
236 }
237 
238 /* remove all the buses */
239 void amdgpu_i2c_fini(struct amdgpu_device *adev)
240 {
241 	int i;
242 
243 	for (i = 0; i < AMDGPU_MAX_I2C_BUS; i++) {
244 		if (adev->i2c_bus[i]) {
245 			amdgpu_i2c_destroy(adev->i2c_bus[i]);
246 			adev->i2c_bus[i] = NULL;
247 		}
248 	}
249 }
250 
251 /* Add additional buses */
252 void amdgpu_i2c_add(struct amdgpu_device *adev,
253 		    const struct amdgpu_i2c_bus_rec *rec,
254 		    const char *name)
255 {
256 	struct drm_device *dev = adev_to_drm(adev);
257 	int i;
258 
259 	for (i = 0; i < AMDGPU_MAX_I2C_BUS; i++) {
260 		if (!adev->i2c_bus[i]) {
261 			adev->i2c_bus[i] = amdgpu_i2c_create(dev, rec, name);
262 			return;
263 		}
264 	}
265 }
266 
267 /* looks up bus based on id */
268 struct amdgpu_i2c_chan *
269 amdgpu_i2c_lookup(struct amdgpu_device *adev,
270 		  const struct amdgpu_i2c_bus_rec *i2c_bus)
271 {
272 	int i;
273 
274 	for (i = 0; i < AMDGPU_MAX_I2C_BUS; i++) {
275 		if (adev->i2c_bus[i] &&
276 		    (adev->i2c_bus[i]->rec.i2c_id == i2c_bus->i2c_id)) {
277 			return adev->i2c_bus[i];
278 		}
279 	}
280 	return NULL;
281 }
282 
283 static void amdgpu_i2c_get_byte(struct amdgpu_i2c_chan *i2c_bus,
284 				 u8 slave_addr,
285 				 u8 addr,
286 				 u8 *val)
287 {
288 	u8 out_buf[2];
289 	u8 in_buf[2];
290 	struct i2c_msg msgs[] = {
291 		{
292 			.addr = slave_addr,
293 			.flags = 0,
294 			.len = 1,
295 			.buf = out_buf,
296 		},
297 		{
298 			.addr = slave_addr,
299 			.flags = I2C_M_RD,
300 			.len = 1,
301 			.buf = in_buf,
302 		}
303 	};
304 
305 	out_buf[0] = addr;
306 	out_buf[1] = 0;
307 
308 	if (i2c_transfer(&i2c_bus->adapter, msgs, 2) == 2) {
309 		*val = in_buf[0];
310 		DRM_DEBUG("val = 0x%02x\n", *val);
311 	} else {
312 		DRM_DEBUG("i2c 0x%02x 0x%02x read failed\n",
313 			  addr, *val);
314 	}
315 }
316 
317 static void amdgpu_i2c_put_byte(struct amdgpu_i2c_chan *i2c_bus,
318 				 u8 slave_addr,
319 				 u8 addr,
320 				 u8 val)
321 {
322 	uint8_t out_buf[2];
323 	struct i2c_msg msg = {
324 		.addr = slave_addr,
325 		.flags = 0,
326 		.len = 2,
327 		.buf = out_buf,
328 	};
329 
330 	out_buf[0] = addr;
331 	out_buf[1] = val;
332 
333 	if (i2c_transfer(&i2c_bus->adapter, &msg, 1) != 1)
334 		DRM_DEBUG("i2c 0x%02x 0x%02x write failed\n",
335 			  addr, val);
336 }
337 
338 /* ddc router switching */
339 void
340 amdgpu_i2c_router_select_ddc_port(const struct amdgpu_connector *amdgpu_connector)
341 {
342 	u8 val;
343 
344 	if (!amdgpu_connector->router.ddc_valid)
345 		return;
346 
347 	if (!amdgpu_connector->router_bus)
348 		return;
349 
350 	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
351 			    amdgpu_connector->router.i2c_addr,
352 			    0x3, &val);
353 	val &= ~amdgpu_connector->router.ddc_mux_control_pin;
354 	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
355 			    amdgpu_connector->router.i2c_addr,
356 			    0x3, val);
357 	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
358 			    amdgpu_connector->router.i2c_addr,
359 			    0x1, &val);
360 	val &= ~amdgpu_connector->router.ddc_mux_control_pin;
361 	val |= amdgpu_connector->router.ddc_mux_state;
362 	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
363 			    amdgpu_connector->router.i2c_addr,
364 			    0x1, val);
365 }
366 
367 /* clock/data router switching */
368 void
369 amdgpu_i2c_router_select_cd_port(const struct amdgpu_connector *amdgpu_connector)
370 {
371 	u8 val;
372 
373 	if (!amdgpu_connector->router.cd_valid)
374 		return;
375 
376 	if (!amdgpu_connector->router_bus)
377 		return;
378 
379 	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
380 			    amdgpu_connector->router.i2c_addr,
381 			    0x3, &val);
382 	val &= ~amdgpu_connector->router.cd_mux_control_pin;
383 	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
384 			    amdgpu_connector->router.i2c_addr,
385 			    0x3, val);
386 	amdgpu_i2c_get_byte(amdgpu_connector->router_bus,
387 			    amdgpu_connector->router.i2c_addr,
388 			    0x1, &val);
389 	val &= ~amdgpu_connector->router.cd_mux_control_pin;
390 	val |= amdgpu_connector->router.cd_mux_state;
391 	amdgpu_i2c_put_byte(amdgpu_connector->router_bus,
392 			    amdgpu_connector->router.i2c_addr,
393 			    0x1, val);
394 }
395