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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2017 Sanechips Technology Co., Ltd.
4  * Copyright 2017 Linaro Ltd.
5  */
6 
7 #include <linux/clk.h>
8 #include <linux/component.h>
9 #include <linux/mfd/syscon.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 
14 #include <drm/drm_atomic_helper.h>
15 #include <drm/drm_print.h>
16 #include <drm/drm_probe_helper.h>
17 #include <drm/drm_simple_kms_helper.h>
18 
19 #include "zx_drm_drv.h"
20 #include "zx_vga_regs.h"
21 #include "zx_vou.h"
22 
23 struct zx_vga_pwrctrl {
24 	struct regmap *regmap;
25 	u32 reg;
26 	u32 mask;
27 };
28 
29 struct zx_vga_i2c {
30 	struct i2c_adapter adap;
31 	struct mutex lock;
32 };
33 
34 struct zx_vga {
35 	struct drm_connector connector;
36 	struct drm_encoder encoder;
37 	struct zx_vga_i2c *ddc;
38 	struct device *dev;
39 	void __iomem *mmio;
40 	struct clk *i2c_wclk;
41 	struct zx_vga_pwrctrl pwrctrl;
42 	struct completion complete;
43 	bool connected;
44 };
45 
46 #define to_zx_vga(x) container_of(x, struct zx_vga, x)
47 
zx_vga_encoder_enable(struct drm_encoder * encoder)48 static void zx_vga_encoder_enable(struct drm_encoder *encoder)
49 {
50 	struct zx_vga *vga = to_zx_vga(encoder);
51 	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
52 
53 	/* Set bit to power up VGA DACs */
54 	regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask,
55 			   pwrctrl->mask);
56 
57 	vou_inf_enable(VOU_VGA, encoder->crtc);
58 }
59 
zx_vga_encoder_disable(struct drm_encoder * encoder)60 static void zx_vga_encoder_disable(struct drm_encoder *encoder)
61 {
62 	struct zx_vga *vga = to_zx_vga(encoder);
63 	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
64 
65 	vou_inf_disable(VOU_VGA, encoder->crtc);
66 
67 	/* Clear bit to power down VGA DACs */
68 	regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask, 0);
69 }
70 
71 static const struct drm_encoder_helper_funcs zx_vga_encoder_helper_funcs = {
72 	.enable	= zx_vga_encoder_enable,
73 	.disable = zx_vga_encoder_disable,
74 };
75 
zx_vga_connector_get_modes(struct drm_connector * connector)76 static int zx_vga_connector_get_modes(struct drm_connector *connector)
77 {
78 	struct zx_vga *vga = to_zx_vga(connector);
79 	struct edid *edid;
80 	int ret;
81 
82 	/*
83 	 * Clear both detection bits to switch I2C bus from device
84 	 * detecting to EDID reading.
85 	 */
86 	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, 0);
87 
88 	edid = drm_get_edid(connector, &vga->ddc->adap);
89 	if (!edid) {
90 		/*
91 		 * If EDID reading fails, we set the device state into
92 		 * disconnected.  Locking is not required here, since the
93 		 * VGA_AUTO_DETECT_SEL register write in irq handler cannot
94 		 * be triggered when both detection bits are cleared as above.
95 		 */
96 		zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
97 			  VGA_DETECT_SEL_NO_DEVICE);
98 		vga->connected = false;
99 		return 0;
100 	}
101 
102 	/*
103 	 * As edid reading succeeds, device must be connected, so we set
104 	 * up detection bit for unplug interrupt here.
105 	 */
106 	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_HAS_DEVICE);
107 
108 	drm_connector_update_edid_property(connector, edid);
109 	ret = drm_add_edid_modes(connector, edid);
110 	kfree(edid);
111 
112 	return ret;
113 }
114 
115 static enum drm_mode_status
zx_vga_connector_mode_valid(struct drm_connector * connector,struct drm_display_mode * mode)116 zx_vga_connector_mode_valid(struct drm_connector *connector,
117 			    struct drm_display_mode *mode)
118 {
119 	return MODE_OK;
120 }
121 
122 static struct drm_connector_helper_funcs zx_vga_connector_helper_funcs = {
123 	.get_modes = zx_vga_connector_get_modes,
124 	.mode_valid = zx_vga_connector_mode_valid,
125 };
126 
127 static enum drm_connector_status
zx_vga_connector_detect(struct drm_connector * connector,bool force)128 zx_vga_connector_detect(struct drm_connector *connector, bool force)
129 {
130 	struct zx_vga *vga = to_zx_vga(connector);
131 
132 	return vga->connected ? connector_status_connected :
133 				connector_status_disconnected;
134 }
135 
136 static const struct drm_connector_funcs zx_vga_connector_funcs = {
137 	.fill_modes = drm_helper_probe_single_connector_modes,
138 	.detect = zx_vga_connector_detect,
139 	.destroy = drm_connector_cleanup,
140 	.reset = drm_atomic_helper_connector_reset,
141 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
142 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
143 };
144 
zx_vga_register(struct drm_device * drm,struct zx_vga * vga)145 static int zx_vga_register(struct drm_device *drm, struct zx_vga *vga)
146 {
147 	struct drm_encoder *encoder = &vga->encoder;
148 	struct drm_connector *connector = &vga->connector;
149 	struct device *dev = vga->dev;
150 	int ret;
151 
152 	encoder->possible_crtcs = VOU_CRTC_MASK;
153 
154 	ret = drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_DAC);
155 	if (ret) {
156 		DRM_DEV_ERROR(dev, "failed to init encoder: %d\n", ret);
157 		return ret;
158 	}
159 
160 	drm_encoder_helper_add(encoder, &zx_vga_encoder_helper_funcs);
161 
162 	vga->connector.polled = DRM_CONNECTOR_POLL_HPD;
163 
164 	ret = drm_connector_init_with_ddc(drm, connector,
165 					  &zx_vga_connector_funcs,
166 					  DRM_MODE_CONNECTOR_VGA,
167 					  &vga->ddc->adap);
168 	if (ret) {
169 		DRM_DEV_ERROR(dev, "failed to init connector: %d\n", ret);
170 		goto clean_encoder;
171 	}
172 
173 	drm_connector_helper_add(connector, &zx_vga_connector_helper_funcs);
174 
175 	ret = drm_connector_attach_encoder(connector, encoder);
176 	if (ret) {
177 		DRM_DEV_ERROR(dev, "failed to attach encoder: %d\n", ret);
178 		goto clean_connector;
179 	}
180 
181 	return 0;
182 
183 clean_connector:
184 	drm_connector_cleanup(connector);
185 clean_encoder:
186 	drm_encoder_cleanup(encoder);
187 	return ret;
188 }
189 
zx_vga_pwrctrl_init(struct zx_vga * vga)190 static int zx_vga_pwrctrl_init(struct zx_vga *vga)
191 {
192 	struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
193 	struct device *dev = vga->dev;
194 	struct of_phandle_args out_args;
195 	struct regmap *regmap;
196 	int ret;
197 
198 	ret = of_parse_phandle_with_fixed_args(dev->of_node,
199 				"zte,vga-power-control", 2, 0, &out_args);
200 	if (ret)
201 		return ret;
202 
203 	regmap = syscon_node_to_regmap(out_args.np);
204 	if (IS_ERR(regmap)) {
205 		ret = PTR_ERR(regmap);
206 		goto out;
207 	}
208 
209 	pwrctrl->regmap = regmap;
210 	pwrctrl->reg = out_args.args[0];
211 	pwrctrl->mask = out_args.args[1];
212 
213 out:
214 	of_node_put(out_args.np);
215 	return ret;
216 }
217 
zx_vga_i2c_read(struct zx_vga * vga,struct i2c_msg * msg)218 static int zx_vga_i2c_read(struct zx_vga *vga, struct i2c_msg *msg)
219 {
220 	int len = msg->len;
221 	u8 *buf = msg->buf;
222 	u32 offset = 0;
223 	int i;
224 
225 	reinit_completion(&vga->complete);
226 
227 	/* Select combo write */
228 	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_COMBO, VGA_CMD_COMBO);
229 	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_RW, 0);
230 
231 	while (len > 0) {
232 		u32 cnt;
233 
234 		/* Clear RX FIFO */
235 		zx_writel_mask(vga->mmio + VGA_RXF_CTRL, VGA_RX_FIFO_CLEAR,
236 			       VGA_RX_FIFO_CLEAR);
237 
238 		/* Data offset to read from */
239 		zx_writel(vga->mmio + VGA_SUB_ADDR, offset);
240 
241 		/* Kick off the transfer */
242 		zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS,
243 			       VGA_CMD_TRANS);
244 
245 		if (!wait_for_completion_timeout(&vga->complete,
246 						 msecs_to_jiffies(1000))) {
247 			DRM_DEV_ERROR(vga->dev, "transfer timeout\n");
248 			return -ETIMEDOUT;
249 		}
250 
251 		cnt = zx_readl(vga->mmio + VGA_RXF_STATUS);
252 		cnt = (cnt & VGA_RXF_COUNT_MASK) >> VGA_RXF_COUNT_SHIFT;
253 		/* FIFO status may report more data than we need to read */
254 		cnt = min_t(u32, len, cnt);
255 
256 		for (i = 0; i < cnt; i++)
257 			*buf++ = zx_readl(vga->mmio + VGA_DATA);
258 
259 		len -= cnt;
260 		offset += cnt;
261 	}
262 
263 	return 0;
264 }
265 
zx_vga_i2c_write(struct zx_vga * vga,struct i2c_msg * msg)266 static int zx_vga_i2c_write(struct zx_vga *vga, struct i2c_msg *msg)
267 {
268 	/*
269 	 * The DDC I2C adapter is only for reading EDID data, so we assume
270 	 * that the write to this adapter must be the EDID data offset.
271 	 */
272 	if ((msg->len != 1) || ((msg->addr != DDC_ADDR)))
273 		return -EINVAL;
274 
275 	/* Hardware will take care of the slave address shifting */
276 	zx_writel(vga->mmio + VGA_DEVICE_ADDR, msg->addr);
277 
278 	return 0;
279 }
280 
zx_vga_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)281 static int zx_vga_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
282 			   int num)
283 {
284 	struct zx_vga *vga = i2c_get_adapdata(adap);
285 	struct zx_vga_i2c *ddc = vga->ddc;
286 	int ret = 0;
287 	int i;
288 
289 	mutex_lock(&ddc->lock);
290 
291 	for (i = 0; i < num; i++) {
292 		if (msgs[i].flags & I2C_M_RD)
293 			ret = zx_vga_i2c_read(vga, &msgs[i]);
294 		else
295 			ret = zx_vga_i2c_write(vga, &msgs[i]);
296 
297 		if (ret < 0)
298 			break;
299 	}
300 
301 	if (!ret)
302 		ret = num;
303 
304 	mutex_unlock(&ddc->lock);
305 
306 	return ret;
307 }
308 
zx_vga_i2c_func(struct i2c_adapter * adapter)309 static u32 zx_vga_i2c_func(struct i2c_adapter *adapter)
310 {
311 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
312 }
313 
314 static const struct i2c_algorithm zx_vga_algorithm = {
315 	.master_xfer	= zx_vga_i2c_xfer,
316 	.functionality	= zx_vga_i2c_func,
317 };
318 
zx_vga_ddc_register(struct zx_vga * vga)319 static int zx_vga_ddc_register(struct zx_vga *vga)
320 {
321 	struct device *dev = vga->dev;
322 	struct i2c_adapter *adap;
323 	struct zx_vga_i2c *ddc;
324 	int ret;
325 
326 	ddc = devm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
327 	if (!ddc)
328 		return -ENOMEM;
329 
330 	vga->ddc = ddc;
331 	mutex_init(&ddc->lock);
332 
333 	adap = &ddc->adap;
334 	adap->owner = THIS_MODULE;
335 	adap->class = I2C_CLASS_DDC;
336 	adap->dev.parent = dev;
337 	adap->algo = &zx_vga_algorithm;
338 	snprintf(adap->name, sizeof(adap->name), "zx vga i2c");
339 
340 	ret = i2c_add_adapter(adap);
341 	if (ret) {
342 		DRM_DEV_ERROR(dev, "failed to add I2C adapter: %d\n", ret);
343 		return ret;
344 	}
345 
346 	i2c_set_adapdata(adap, vga);
347 
348 	return 0;
349 }
350 
zx_vga_irq_thread(int irq,void * dev_id)351 static irqreturn_t zx_vga_irq_thread(int irq, void *dev_id)
352 {
353 	struct zx_vga *vga = dev_id;
354 
355 	drm_helper_hpd_irq_event(vga->connector.dev);
356 
357 	return IRQ_HANDLED;
358 }
359 
zx_vga_irq_handler(int irq,void * dev_id)360 static irqreturn_t zx_vga_irq_handler(int irq, void *dev_id)
361 {
362 	struct zx_vga *vga = dev_id;
363 	u32 status;
364 
365 	status = zx_readl(vga->mmio + VGA_I2C_STATUS);
366 
367 	/* Clear interrupt status */
368 	zx_writel_mask(vga->mmio + VGA_I2C_STATUS, VGA_CLEAR_IRQ,
369 		       VGA_CLEAR_IRQ);
370 
371 	if (status & VGA_DEVICE_CONNECTED) {
372 		/*
373 		 * Since VGA_DETECT_SEL bits need to be reset for switching DDC
374 		 * bus from device detection to EDID read, rather than setting
375 		 * up HAS_DEVICE bit here, we need to do that in .get_modes
376 		 * hook for unplug detecting after EDID read succeeds.
377 		 */
378 		vga->connected = true;
379 		return IRQ_WAKE_THREAD;
380 	}
381 
382 	if (status & VGA_DEVICE_DISCONNECTED) {
383 		zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
384 			  VGA_DETECT_SEL_NO_DEVICE);
385 		vga->connected = false;
386 		return IRQ_WAKE_THREAD;
387 	}
388 
389 	if (status & VGA_TRANS_DONE) {
390 		complete(&vga->complete);
391 		return IRQ_HANDLED;
392 	}
393 
394 	return IRQ_NONE;
395 }
396 
zx_vga_hw_init(struct zx_vga * vga)397 static void zx_vga_hw_init(struct zx_vga *vga)
398 {
399 	unsigned long ref = clk_get_rate(vga->i2c_wclk);
400 	int div;
401 
402 	/*
403 	 * Set up I2C fast speed divider per formula below to get 400kHz.
404 	 *   scl = ref / ((div + 1) * 4)
405 	 */
406 	div = DIV_ROUND_UP(ref / 1000, 400 * 4) - 1;
407 	zx_writel(vga->mmio + VGA_CLK_DIV_FS, div);
408 
409 	/* Set up device detection */
410 	zx_writel(vga->mmio + VGA_AUTO_DETECT_PARA, 0x80);
411 	zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_NO_DEVICE);
412 
413 	/*
414 	 * We need to poke monitor via DDC bus to get connection irq
415 	 * start working.
416 	 */
417 	zx_writel(vga->mmio + VGA_DEVICE_ADDR, DDC_ADDR);
418 	zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS, VGA_CMD_TRANS);
419 }
420 
zx_vga_bind(struct device * dev,struct device * master,void * data)421 static int zx_vga_bind(struct device *dev, struct device *master, void *data)
422 {
423 	struct platform_device *pdev = to_platform_device(dev);
424 	struct drm_device *drm = data;
425 	struct resource *res;
426 	struct zx_vga *vga;
427 	int irq;
428 	int ret;
429 
430 	vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
431 	if (!vga)
432 		return -ENOMEM;
433 
434 	vga->dev = dev;
435 	dev_set_drvdata(dev, vga);
436 
437 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
438 	vga->mmio = devm_ioremap_resource(dev, res);
439 	if (IS_ERR(vga->mmio))
440 		return PTR_ERR(vga->mmio);
441 
442 	irq = platform_get_irq(pdev, 0);
443 	if (irq < 0)
444 		return irq;
445 
446 	vga->i2c_wclk = devm_clk_get(dev, "i2c_wclk");
447 	if (IS_ERR(vga->i2c_wclk)) {
448 		ret = PTR_ERR(vga->i2c_wclk);
449 		DRM_DEV_ERROR(dev, "failed to get i2c_wclk: %d\n", ret);
450 		return ret;
451 	}
452 
453 	ret = zx_vga_pwrctrl_init(vga);
454 	if (ret) {
455 		DRM_DEV_ERROR(dev, "failed to init power control: %d\n", ret);
456 		return ret;
457 	}
458 
459 	ret = zx_vga_ddc_register(vga);
460 	if (ret) {
461 		DRM_DEV_ERROR(dev, "failed to register ddc: %d\n", ret);
462 		return ret;
463 	}
464 
465 	ret = zx_vga_register(drm, vga);
466 	if (ret) {
467 		DRM_DEV_ERROR(dev, "failed to register vga: %d\n", ret);
468 		return ret;
469 	}
470 
471 	init_completion(&vga->complete);
472 
473 	ret = devm_request_threaded_irq(dev, irq, zx_vga_irq_handler,
474 					zx_vga_irq_thread, IRQF_SHARED,
475 					dev_name(dev), vga);
476 	if (ret) {
477 		DRM_DEV_ERROR(dev, "failed to request threaded irq: %d\n", ret);
478 		return ret;
479 	}
480 
481 	ret = clk_prepare_enable(vga->i2c_wclk);
482 	if (ret)
483 		return ret;
484 
485 	zx_vga_hw_init(vga);
486 
487 	return 0;
488 }
489 
zx_vga_unbind(struct device * dev,struct device * master,void * data)490 static void zx_vga_unbind(struct device *dev, struct device *master,
491 			  void *data)
492 {
493 	struct zx_vga *vga = dev_get_drvdata(dev);
494 
495 	clk_disable_unprepare(vga->i2c_wclk);
496 }
497 
498 static const struct component_ops zx_vga_component_ops = {
499 	.bind = zx_vga_bind,
500 	.unbind = zx_vga_unbind,
501 };
502 
zx_vga_probe(struct platform_device * pdev)503 static int zx_vga_probe(struct platform_device *pdev)
504 {
505 	return component_add(&pdev->dev, &zx_vga_component_ops);
506 }
507 
zx_vga_remove(struct platform_device * pdev)508 static int zx_vga_remove(struct platform_device *pdev)
509 {
510 	component_del(&pdev->dev, &zx_vga_component_ops);
511 	return 0;
512 }
513 
514 static const struct of_device_id zx_vga_of_match[] = {
515 	{ .compatible = "zte,zx296718-vga", },
516 	{ /* end */ },
517 };
518 MODULE_DEVICE_TABLE(of, zx_vga_of_match);
519 
520 struct platform_driver zx_vga_driver = {
521 	.probe = zx_vga_probe,
522 	.remove = zx_vga_remove,
523 	.driver	= {
524 		.name = "zx-vga",
525 		.of_match_table	= zx_vga_of_match,
526 	},
527 };
528