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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
18#include "zx_drm_drv.h"
19#include "zx_vga_regs.h"
20#include "zx_vou.h"
21
22struct zx_vga_pwrctrl {
23 struct regmap *regmap;
24 u32 reg;
25 u32 mask;
26};
27
28struct zx_vga_i2c {
29 struct i2c_adapter adap;
30 struct mutex lock;
31};
32
33struct zx_vga {
34 struct drm_connector connector;
35 struct drm_encoder encoder;
36 struct zx_vga_i2c *ddc;
37 struct device *dev;
38 void __iomem *mmio;
39 struct clk *i2c_wclk;
40 struct zx_vga_pwrctrl pwrctrl;
41 struct completion complete;
42 bool connected;
43};
44
45#define to_zx_vga(x) container_of(x, struct zx_vga, x)
46
47static void zx_vga_encoder_enable(struct drm_encoder *encoder)
48{
49 struct zx_vga *vga = to_zx_vga(encoder);
50 struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
51
52 /* Set bit to power up VGA DACs */
53 regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask,
54 pwrctrl->mask);
55
56 vou_inf_enable(VOU_VGA, encoder->crtc);
57}
58
59static void zx_vga_encoder_disable(struct drm_encoder *encoder)
60{
61 struct zx_vga *vga = to_zx_vga(encoder);
62 struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
63
64 vou_inf_disable(VOU_VGA, encoder->crtc);
65
66 /* Clear bit to power down VGA DACs */
67 regmap_update_bits(pwrctrl->regmap, pwrctrl->reg, pwrctrl->mask, 0);
68}
69
70static const struct drm_encoder_helper_funcs zx_vga_encoder_helper_funcs = {
71 .enable = zx_vga_encoder_enable,
72 .disable = zx_vga_encoder_disable,
73};
74
75static const struct drm_encoder_funcs zx_vga_encoder_funcs = {
76 .destroy = drm_encoder_cleanup,
77};
78
79static int zx_vga_connector_get_modes(struct drm_connector *connector)
80{
81 struct zx_vga *vga = to_zx_vga(connector);
82 struct edid *edid;
83 int ret;
84
85 /*
86 * Clear both detection bits to switch I2C bus from device
87 * detecting to EDID reading.
88 */
89 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, 0);
90
91 edid = drm_get_edid(connector, &vga->ddc->adap);
92 if (!edid) {
93 /*
94 * If EDID reading fails, we set the device state into
95 * disconnected. Locking is not required here, since the
96 * VGA_AUTO_DETECT_SEL register write in irq handler cannot
97 * be triggered when both detection bits are cleared as above.
98 */
99 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
100 VGA_DETECT_SEL_NO_DEVICE);
101 vga->connected = false;
102 return 0;
103 }
104
105 /*
106 * As edid reading succeeds, device must be connected, so we set
107 * up detection bit for unplug interrupt here.
108 */
109 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_HAS_DEVICE);
110
111 drm_connector_update_edid_property(connector, edid);
112 ret = drm_add_edid_modes(connector, edid);
113 kfree(edid);
114
115 return ret;
116}
117
118static enum drm_mode_status
119zx_vga_connector_mode_valid(struct drm_connector *connector,
120 struct drm_display_mode *mode)
121{
122 return MODE_OK;
123}
124
125static struct drm_connector_helper_funcs zx_vga_connector_helper_funcs = {
126 .get_modes = zx_vga_connector_get_modes,
127 .mode_valid = zx_vga_connector_mode_valid,
128};
129
130static enum drm_connector_status
131zx_vga_connector_detect(struct drm_connector *connector, bool force)
132{
133 struct zx_vga *vga = to_zx_vga(connector);
134
135 return vga->connected ? connector_status_connected :
136 connector_status_disconnected;
137}
138
139static const struct drm_connector_funcs zx_vga_connector_funcs = {
140 .fill_modes = drm_helper_probe_single_connector_modes,
141 .detect = zx_vga_connector_detect,
142 .destroy = drm_connector_cleanup,
143 .reset = drm_atomic_helper_connector_reset,
144 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
145 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
146};
147
148static int zx_vga_register(struct drm_device *drm, struct zx_vga *vga)
149{
150 struct drm_encoder *encoder = &vga->encoder;
151 struct drm_connector *connector = &vga->connector;
152 struct device *dev = vga->dev;
153 int ret;
154
155 encoder->possible_crtcs = VOU_CRTC_MASK;
156
157 ret = drm_encoder_init(drm, encoder, &zx_vga_encoder_funcs,
158 DRM_MODE_ENCODER_DAC, NULL);
159 if (ret) {
160 DRM_DEV_ERROR(dev, "failed to init encoder: %d\n", ret);
161 return ret;
162 };
163
164 drm_encoder_helper_add(encoder, &zx_vga_encoder_helper_funcs);
165
166 vga->connector.polled = DRM_CONNECTOR_POLL_HPD;
167
168 ret = drm_connector_init(drm, connector, &zx_vga_connector_funcs,
169 DRM_MODE_CONNECTOR_VGA);
170 if (ret) {
171 DRM_DEV_ERROR(dev, "failed to init connector: %d\n", ret);
172 goto clean_encoder;
173 };
174
175 drm_connector_helper_add(connector, &zx_vga_connector_helper_funcs);
176
177 ret = drm_connector_attach_encoder(connector, encoder);
178 if (ret) {
179 DRM_DEV_ERROR(dev, "failed to attach encoder: %d\n", ret);
180 goto clean_connector;
181 };
182
183 return 0;
184
185clean_connector:
186 drm_connector_cleanup(connector);
187clean_encoder:
188 drm_encoder_cleanup(encoder);
189 return ret;
190}
191
192static int zx_vga_pwrctrl_init(struct zx_vga *vga)
193{
194 struct zx_vga_pwrctrl *pwrctrl = &vga->pwrctrl;
195 struct device *dev = vga->dev;
196 struct of_phandle_args out_args;
197 struct regmap *regmap;
198 int ret;
199
200 ret = of_parse_phandle_with_fixed_args(dev->of_node,
201 "zte,vga-power-control", 2, 0, &out_args);
202 if (ret)
203 return ret;
204
205 regmap = syscon_node_to_regmap(out_args.np);
206 if (IS_ERR(regmap)) {
207 ret = PTR_ERR(regmap);
208 goto out;
209 }
210
211 pwrctrl->regmap = regmap;
212 pwrctrl->reg = out_args.args[0];
213 pwrctrl->mask = out_args.args[1];
214
215out:
216 of_node_put(out_args.np);
217 return ret;
218}
219
220static int zx_vga_i2c_read(struct zx_vga *vga, struct i2c_msg *msg)
221{
222 int len = msg->len;
223 u8 *buf = msg->buf;
224 u32 offset = 0;
225 int i;
226
227 reinit_completion(&vga->complete);
228
229 /* Select combo write */
230 zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_COMBO, VGA_CMD_COMBO);
231 zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_RW, 0);
232
233 while (len > 0) {
234 u32 cnt;
235
236 /* Clear RX FIFO */
237 zx_writel_mask(vga->mmio + VGA_RXF_CTRL, VGA_RX_FIFO_CLEAR,
238 VGA_RX_FIFO_CLEAR);
239
240 /* Data offset to read from */
241 zx_writel(vga->mmio + VGA_SUB_ADDR, offset);
242
243 /* Kick off the transfer */
244 zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS,
245 VGA_CMD_TRANS);
246
247 if (!wait_for_completion_timeout(&vga->complete,
248 msecs_to_jiffies(1000))) {
249 DRM_DEV_ERROR(vga->dev, "transfer timeout\n");
250 return -ETIMEDOUT;
251 }
252
253 cnt = zx_readl(vga->mmio + VGA_RXF_STATUS);
254 cnt = (cnt & VGA_RXF_COUNT_MASK) >> VGA_RXF_COUNT_SHIFT;
255 /* FIFO status may report more data than we need to read */
256 cnt = min_t(u32, len, cnt);
257
258 for (i = 0; i < cnt; i++)
259 *buf++ = zx_readl(vga->mmio + VGA_DATA);
260
261 len -= cnt;
262 offset += cnt;
263 }
264
265 return 0;
266}
267
268static int zx_vga_i2c_write(struct zx_vga *vga, struct i2c_msg *msg)
269{
270 /*
271 * The DDC I2C adapter is only for reading EDID data, so we assume
272 * that the write to this adapter must be the EDID data offset.
273 */
274 if ((msg->len != 1) || ((msg->addr != DDC_ADDR)))
275 return -EINVAL;
276
277 /* Hardware will take care of the slave address shifting */
278 zx_writel(vga->mmio + VGA_DEVICE_ADDR, msg->addr);
279
280 return 0;
281}
282
283static int zx_vga_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
284 int num)
285{
286 struct zx_vga *vga = i2c_get_adapdata(adap);
287 struct zx_vga_i2c *ddc = vga->ddc;
288 int ret = 0;
289 int i;
290
291 mutex_lock(&ddc->lock);
292
293 for (i = 0; i < num; i++) {
294 if (msgs[i].flags & I2C_M_RD)
295 ret = zx_vga_i2c_read(vga, &msgs[i]);
296 else
297 ret = zx_vga_i2c_write(vga, &msgs[i]);
298
299 if (ret < 0)
300 break;
301 }
302
303 if (!ret)
304 ret = num;
305
306 mutex_unlock(&ddc->lock);
307
308 return ret;
309}
310
311static u32 zx_vga_i2c_func(struct i2c_adapter *adapter)
312{
313 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
314}
315
316static const struct i2c_algorithm zx_vga_algorithm = {
317 .master_xfer = zx_vga_i2c_xfer,
318 .functionality = zx_vga_i2c_func,
319};
320
321static int zx_vga_ddc_register(struct zx_vga *vga)
322{
323 struct device *dev = vga->dev;
324 struct i2c_adapter *adap;
325 struct zx_vga_i2c *ddc;
326 int ret;
327
328 ddc = devm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
329 if (!ddc)
330 return -ENOMEM;
331
332 vga->ddc = ddc;
333 mutex_init(&ddc->lock);
334
335 adap = &ddc->adap;
336 adap->owner = THIS_MODULE;
337 adap->class = I2C_CLASS_DDC;
338 adap->dev.parent = dev;
339 adap->algo = &zx_vga_algorithm;
340 snprintf(adap->name, sizeof(adap->name), "zx vga i2c");
341
342 ret = i2c_add_adapter(adap);
343 if (ret) {
344 DRM_DEV_ERROR(dev, "failed to add I2C adapter: %d\n", ret);
345 return ret;
346 }
347
348 i2c_set_adapdata(adap, vga);
349
350 return 0;
351}
352
353static irqreturn_t zx_vga_irq_thread(int irq, void *dev_id)
354{
355 struct zx_vga *vga = dev_id;
356
357 drm_helper_hpd_irq_event(vga->connector.dev);
358
359 return IRQ_HANDLED;
360}
361
362static irqreturn_t zx_vga_irq_handler(int irq, void *dev_id)
363{
364 struct zx_vga *vga = dev_id;
365 u32 status;
366
367 status = zx_readl(vga->mmio + VGA_I2C_STATUS);
368
369 /* Clear interrupt status */
370 zx_writel_mask(vga->mmio + VGA_I2C_STATUS, VGA_CLEAR_IRQ,
371 VGA_CLEAR_IRQ);
372
373 if (status & VGA_DEVICE_CONNECTED) {
374 /*
375 * Since VGA_DETECT_SEL bits need to be reset for switching DDC
376 * bus from device detection to EDID read, rather than setting
377 * up HAS_DEVICE bit here, we need to do that in .get_modes
378 * hook for unplug detecting after EDID read succeeds.
379 */
380 vga->connected = true;
381 return IRQ_WAKE_THREAD;
382 }
383
384 if (status & VGA_DEVICE_DISCONNECTED) {
385 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL,
386 VGA_DETECT_SEL_NO_DEVICE);
387 vga->connected = false;
388 return IRQ_WAKE_THREAD;
389 }
390
391 if (status & VGA_TRANS_DONE) {
392 complete(&vga->complete);
393 return IRQ_HANDLED;
394 }
395
396 return IRQ_NONE;
397}
398
399static void zx_vga_hw_init(struct zx_vga *vga)
400{
401 unsigned long ref = clk_get_rate(vga->i2c_wclk);
402 int div;
403
404 /*
405 * Set up I2C fast speed divider per formula below to get 400kHz.
406 * scl = ref / ((div + 1) * 4)
407 */
408 div = DIV_ROUND_UP(ref / 1000, 400 * 4) - 1;
409 zx_writel(vga->mmio + VGA_CLK_DIV_FS, div);
410
411 /* Set up device detection */
412 zx_writel(vga->mmio + VGA_AUTO_DETECT_PARA, 0x80);
413 zx_writel(vga->mmio + VGA_AUTO_DETECT_SEL, VGA_DETECT_SEL_NO_DEVICE);
414
415 /*
416 * We need to poke monitor via DDC bus to get connection irq
417 * start working.
418 */
419 zx_writel(vga->mmio + VGA_DEVICE_ADDR, DDC_ADDR);
420 zx_writel_mask(vga->mmio + VGA_CMD_CFG, VGA_CMD_TRANS, VGA_CMD_TRANS);
421}
422
423static int zx_vga_bind(struct device *dev, struct device *master, void *data)
424{
425 struct platform_device *pdev = to_platform_device(dev);
426 struct drm_device *drm = data;
427 struct resource *res;
428 struct zx_vga *vga;
429 int irq;
430 int ret;
431
432 vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
433 if (!vga)
434 return -ENOMEM;
435
436 vga->dev = dev;
437 dev_set_drvdata(dev, vga);
438
439 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
440 vga->mmio = devm_ioremap_resource(dev, res);
441 if (IS_ERR(vga->mmio))
442 return PTR_ERR(vga->mmio);
443
444 irq = platform_get_irq(pdev, 0);
445 if (irq < 0)
446 return irq;
447
448 vga->i2c_wclk = devm_clk_get(dev, "i2c_wclk");
449 if (IS_ERR(vga->i2c_wclk)) {
450 ret = PTR_ERR(vga->i2c_wclk);
451 DRM_DEV_ERROR(dev, "failed to get i2c_wclk: %d\n", ret);
452 return ret;
453 }
454
455 ret = zx_vga_pwrctrl_init(vga);
456 if (ret) {
457 DRM_DEV_ERROR(dev, "failed to init power control: %d\n", ret);
458 return ret;
459 }
460
461 ret = zx_vga_ddc_register(vga);
462 if (ret) {
463 DRM_DEV_ERROR(dev, "failed to register ddc: %d\n", ret);
464 return ret;
465 }
466
467 ret = zx_vga_register(drm, vga);
468 if (ret) {
469 DRM_DEV_ERROR(dev, "failed to register vga: %d\n", ret);
470 return ret;
471 }
472
473 init_completion(&vga->complete);
474
475 ret = devm_request_threaded_irq(dev, irq, zx_vga_irq_handler,
476 zx_vga_irq_thread, IRQF_SHARED,
477 dev_name(dev), vga);
478 if (ret) {
479 DRM_DEV_ERROR(dev, "failed to request threaded irq: %d\n", ret);
480 return ret;
481 }
482
483 ret = clk_prepare_enable(vga->i2c_wclk);
484 if (ret)
485 return ret;
486
487 zx_vga_hw_init(vga);
488
489 return 0;
490}
491
492static void zx_vga_unbind(struct device *dev, struct device *master,
493 void *data)
494{
495 struct zx_vga *vga = dev_get_drvdata(dev);
496
497 clk_disable_unprepare(vga->i2c_wclk);
498}
499
500static const struct component_ops zx_vga_component_ops = {
501 .bind = zx_vga_bind,
502 .unbind = zx_vga_unbind,
503};
504
505static int zx_vga_probe(struct platform_device *pdev)
506{
507 return component_add(&pdev->dev, &zx_vga_component_ops);
508}
509
510static int zx_vga_remove(struct platform_device *pdev)
511{
512 component_del(&pdev->dev, &zx_vga_component_ops);
513 return 0;
514}
515
516static const struct of_device_id zx_vga_of_match[] = {
517 { .compatible = "zte,zx296718-vga", },
518 { /* end */ },
519};
520MODULE_DEVICE_TABLE(of, zx_vga_of_match);
521
522struct platform_driver zx_vga_driver = {
523 .probe = zx_vga_probe,
524 .remove = zx_vga_remove,
525 .driver = {
526 .name = "zx-vga",
527 .of_match_table = zx_vga_of_match,
528 },
529};