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
23struct zx_vga_pwrctrl {
24	struct regmap *regmap;
25	u32 reg;
26	u32 mask;
27};
28
29struct zx_vga_i2c {
30	struct i2c_adapter adap;
31	struct mutex lock;
32};
33
34struct 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
48static 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
60static 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
71static 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
76static 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
115static enum drm_mode_status
116zx_vga_connector_mode_valid(struct drm_connector *connector,
117			    struct drm_display_mode *mode)
118{
119	return MODE_OK;
120}
121
122static 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
127static enum drm_connector_status
128zx_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
136static 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
145static 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
183clean_connector:
184	drm_connector_cleanup(connector);
185clean_encoder:
186	drm_encoder_cleanup(encoder);
187	return ret;
188}
189
190static 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
213out:
214	of_node_put(out_args.np);
215	return ret;
216}
217
218static 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
266static 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
281static 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
309static u32 zx_vga_i2c_func(struct i2c_adapter *adapter)
310{
311	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
312}
313
314static const struct i2c_algorithm zx_vga_algorithm = {
315	.master_xfer	= zx_vga_i2c_xfer,
316	.functionality	= zx_vga_i2c_func,
317};
318
319static 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
351static 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
360static 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
397static 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
421static 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
490static 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
498static const struct component_ops zx_vga_component_ops = {
499	.bind = zx_vga_bind,
500	.unbind = zx_vga_unbind,
501};
502
503static int zx_vga_probe(struct platform_device *pdev)
504{
505	return component_add(&pdev->dev, &zx_vga_component_ops);
506}
507
508static int zx_vga_remove(struct platform_device *pdev)
509{
510	component_del(&pdev->dev, &zx_vga_component_ops);
511	return 0;
512}
513
514static const struct of_device_id zx_vga_of_match[] = {
515	{ .compatible = "zte,zx296718-vga", },
516	{ /* end */ },
517};
518MODULE_DEVICE_TABLE(of, zx_vga_of_match);
519
520struct 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