xref: /linux/drivers/gpu/drm/imx/lcdc/imx-lcdc.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0-only
2 // SPDX-FileCopyrightText: 2020 Marian Cichy <M.Cichy@pengutronix.de>
3 
4 #include <drm/drm_bridge.h>
5 #include <drm/drm_bridge_connector.h>
6 #include <drm/drm_client_setup.h>
7 #include <drm/drm_damage_helper.h>
8 #include <drm/drm_drv.h>
9 #include <drm/drm_fbdev_dma.h>
10 #include <drm/drm_fb_dma_helper.h>
11 #include <drm/drm_fourcc.h>
12 #include <drm/drm_framebuffer.h>
13 #include <drm/drm_gem_atomic_helper.h>
14 #include <drm/drm_gem_dma_helper.h>
15 #include <drm/drm_gem_framebuffer_helper.h>
16 #include <drm/drm_of.h>
17 #include <drm/drm_probe_helper.h>
18 #include <drm/drm_simple_kms_helper.h>
19 #include <drm/drm_vblank.h>
20 #include <linux/bitfield.h>
21 #include <linux/clk.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/mod_devicetable.h>
24 #include <linux/module.h>
25 #include <linux/platform_device.h>
26 
27 #define IMX21LCDC_LSSAR         0x0000 /* LCDC Screen Start Address Register */
28 #define IMX21LCDC_LSR           0x0004 /* LCDC Size Register */
29 #define IMX21LCDC_LVPWR         0x0008 /* LCDC Virtual Page Width Register */
30 #define IMX21LCDC_LCPR          0x000C /* LCDC Cursor Position Register */
31 #define IMX21LCDC_LCWHB         0x0010 /* LCDC Cursor Width Height and Blink Register*/
32 #define IMX21LCDC_LCCMR         0x0014 /* LCDC Color Cursor Mapping Register */
33 #define IMX21LCDC_LPCR          0x0018 /* LCDC Panel Configuration Register */
34 #define IMX21LCDC_LHCR          0x001C /* LCDC Horizontal Configuration Register */
35 #define IMX21LCDC_LVCR          0x0020 /* LCDC Vertical Configuration Register */
36 #define IMX21LCDC_LPOR          0x0024 /* LCDC Panning Offset Register */
37 #define IMX21LCDC_LSCR          0x0028 /* LCDC Sharp Configuration Register */
38 #define IMX21LCDC_LPCCR         0x002C /* LCDC PWM Contrast Control Register */
39 #define IMX21LCDC_LDCR          0x0030 /* LCDC DMA Control Register */
40 #define IMX21LCDC_LRMCR         0x0034 /* LCDC Refresh Mode Control Register */
41 #define IMX21LCDC_LICR          0x0038 /* LCDC Interrupt Configuration Register */
42 #define IMX21LCDC_LIER          0x003C /* LCDC Interrupt Enable Register */
43 #define IMX21LCDC_LISR          0x0040 /* LCDC Interrupt Status Register */
44 #define IMX21LCDC_LGWSAR        0x0050 /* LCDC Graphic Window Start Address Register */
45 #define IMX21LCDC_LGWSR         0x0054 /* LCDC Graph Window Size Register */
46 #define IMX21LCDC_LGWVPWR       0x0058 /* LCDC Graphic Window Virtual Page Width Register */
47 #define IMX21LCDC_LGWPOR        0x005C /* LCDC Graphic Window Panning Offset Register */
48 #define IMX21LCDC_LGWPR         0x0060 /* LCDC Graphic Window Position Register */
49 #define IMX21LCDC_LGWCR         0x0064 /* LCDC Graphic Window Control Register */
50 #define IMX21LCDC_LGWDCR        0x0068 /* LCDC Graphic Window DMA Control Register */
51 #define IMX21LCDC_LAUSCR        0x0080 /* LCDC AUS Mode Control Register */
52 #define IMX21LCDC_LAUSCCR       0x0084 /* LCDC AUS Mode Cursor Control Register */
53 #define IMX21LCDC_BGLUT         0x0800 /* Background Lookup Table */
54 #define IMX21LCDC_GWLUT         0x0C00 /* Graphic Window Lookup Table */
55 
56 #define IMX21LCDC_LCPR_CC0 BIT(30) /* Cursor Control Bit 0 */
57 #define IMX21LCDC_LCPR_CC1 BIT(31) /* Cursor Control Bit 1 */
58 
59 /* Values HSYNC, VSYNC and Framesize Register */
60 #define IMX21LCDC_LHCR_HWIDTH		GENMASK(31, 26)
61 #define IMX21LCDC_LHCR_HFPORCH		GENMASK(15, 8)		/* H_WAIT_1 in the i.MX25 Reference manual */
62 #define IMX21LCDC_LHCR_HBPORCH		GENMASK(7, 0)		/* H_WAIT_2 in the i.MX25 Reference manual */
63 
64 #define IMX21LCDC_LVCR_VWIDTH		GENMASK(31, 26)
65 #define IMX21LCDC_LVCR_VFPORCH		GENMASK(15, 8)		/* V_WAIT_1 in the i.MX25 Reference manual */
66 #define IMX21LCDC_LVCR_VBPORCH		GENMASK(7, 0)		/* V_WAIT_2 in the i.MX25 Reference manual */
67 
68 #define IMX21LCDC_LSR_XMAX		GENMASK(25, 20)
69 #define IMX21LCDC_LSR_YMAX		GENMASK(9, 0)
70 
71 /* Values for LPCR Register */
72 #define IMX21LCDC_LPCR_PCD		GENMASK(5, 0)
73 #define IMX21LCDC_LPCR_SHARP		BIT(6)
74 #define IMX21LCDC_LPCR_SCLKSEL		BIT(7)
75 #define IMX21LCDC_LPCR_ACD		GENMASK(14, 8)
76 #define IMX21LCDC_LPCR_ACDSEL		BIT(15)
77 #define IMX21LCDC_LPCR_REV_VS		BIT(16)
78 #define IMX21LCDC_LPCR_SWAP_SEL		BIT(17)
79 #define IMX21LCDC_LPCR_END_SEL		BIT(18)
80 #define IMX21LCDC_LPCR_SCLKIDLE		BIT(19)
81 #define IMX21LCDC_LPCR_OEPOL		BIT(20)
82 #define IMX21LCDC_LPCR_CLKPOL		BIT(21)
83 #define IMX21LCDC_LPCR_LPPOL		BIT(22)
84 #define IMX21LCDC_LPCR_FLMPOL		BIT(23)
85 #define IMX21LCDC_LPCR_PIXPOL		BIT(24)
86 #define IMX21LCDC_LPCR_BPIX		GENMASK(27, 25)
87 #define IMX21LCDC_LPCR_PBSIZ		GENMASK(29, 28)
88 #define IMX21LCDC_LPCR_COLOR		BIT(30)
89 #define IMX21LCDC_LPCR_TFT		BIT(31)
90 
91 #define INTR_EOF BIT(1) /* VBLANK Interrupt Bit */
92 
93 #define BPP_RGB565	0x05
94 #define BPP_XRGB8888	0x07
95 
96 #define LCDC_MIN_XRES 64
97 #define LCDC_MIN_YRES 64
98 
99 #define LCDC_MAX_XRES 1024
100 #define LCDC_MAX_YRES 1024
101 
102 struct imx_lcdc {
103 	struct drm_device drm;
104 	struct drm_simple_display_pipe pipe;
105 	struct drm_connector *connector;
106 	void __iomem *base;
107 
108 	struct clk *clk_ipg;
109 	struct clk *clk_ahb;
110 	struct clk *clk_per;
111 };
112 
113 static const u32 imx_lcdc_formats[] = {
114 	DRM_FORMAT_RGB565, DRM_FORMAT_XRGB8888,
115 };
116 
117 static inline struct imx_lcdc *imx_lcdc_from_drmdev(struct drm_device *drm)
118 {
119 	return container_of(drm, struct imx_lcdc, drm);
120 }
121 
122 static unsigned int imx_lcdc_get_format(unsigned int drm_format)
123 {
124 	switch (drm_format) {
125 	default:
126 		DRM_WARN("Format not supported - fallback to XRGB8888\n");
127 		fallthrough;
128 
129 	case DRM_FORMAT_XRGB8888:
130 		return BPP_XRGB8888;
131 
132 	case DRM_FORMAT_RGB565:
133 		return BPP_RGB565;
134 	}
135 }
136 
137 static void imx_lcdc_update_hw_registers(struct drm_simple_display_pipe *pipe,
138 					 struct drm_plane_state *old_state,
139 					 bool mode_set)
140 {
141 	struct drm_crtc *crtc = &pipe->crtc;
142 	struct drm_plane_state *new_state = pipe->plane.state;
143 	struct drm_framebuffer *fb = new_state->fb;
144 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
145 	u32 lpcr, lvcr, lhcr;
146 	u32 framesize;
147 	dma_addr_t addr;
148 
149 	addr = drm_fb_dma_get_gem_addr(fb, new_state, 0);
150 	/* The LSSAR register specifies the LCD screen start address (SSA). */
151 	writel(addr, lcdc->base + IMX21LCDC_LSSAR);
152 
153 	if (!mode_set)
154 		return;
155 
156 	/* Disable PER clock to make register write possible */
157 	if (old_state && old_state->crtc && old_state->crtc->enabled)
158 		clk_disable_unprepare(lcdc->clk_per);
159 
160 	/* Framesize */
161 	framesize = FIELD_PREP(IMX21LCDC_LSR_XMAX, crtc->mode.hdisplay >> 4) |
162 		FIELD_PREP(IMX21LCDC_LSR_YMAX, crtc->mode.vdisplay);
163 	writel(framesize, lcdc->base + IMX21LCDC_LSR);
164 
165 	/* HSYNC */
166 	lhcr = FIELD_PREP(IMX21LCDC_LHCR_HFPORCH, crtc->mode.hsync_start - crtc->mode.hdisplay - 1) |
167 		FIELD_PREP(IMX21LCDC_LHCR_HWIDTH, crtc->mode.hsync_end - crtc->mode.hsync_start - 1) |
168 		FIELD_PREP(IMX21LCDC_LHCR_HBPORCH, crtc->mode.htotal - crtc->mode.hsync_end - 3);
169 	writel(lhcr, lcdc->base + IMX21LCDC_LHCR);
170 
171 	/* VSYNC */
172 	lvcr = FIELD_PREP(IMX21LCDC_LVCR_VFPORCH, crtc->mode.vsync_start - crtc->mode.vdisplay) |
173 		FIELD_PREP(IMX21LCDC_LVCR_VWIDTH, crtc->mode.vsync_end - crtc->mode.vsync_start) |
174 		FIELD_PREP(IMX21LCDC_LVCR_VBPORCH, crtc->mode.vtotal - crtc->mode.vsync_end);
175 	writel(lvcr, lcdc->base + IMX21LCDC_LVCR);
176 
177 	lpcr = readl(lcdc->base + IMX21LCDC_LPCR);
178 	lpcr &= ~IMX21LCDC_LPCR_BPIX;
179 	lpcr |= FIELD_PREP(IMX21LCDC_LPCR_BPIX, imx_lcdc_get_format(fb->format->format));
180 	writel(lpcr, lcdc->base + IMX21LCDC_LPCR);
181 
182 	/* Virtual Page Width */
183 	writel(new_state->fb->pitches[0] / 4, lcdc->base + IMX21LCDC_LVPWR);
184 
185 	/* Enable PER clock */
186 	if (new_state->crtc->enabled)
187 		clk_prepare_enable(lcdc->clk_per);
188 }
189 
190 static void imx_lcdc_pipe_enable(struct drm_simple_display_pipe *pipe,
191 				 struct drm_crtc_state *crtc_state,
192 				 struct drm_plane_state *plane_state)
193 {
194 	int ret;
195 	int clk_div;
196 	int bpp;
197 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
198 	struct drm_display_mode *mode = &pipe->crtc.mode;
199 	struct drm_display_info *disp_info = &lcdc->connector->display_info;
200 	const int hsync_pol = (mode->flags & DRM_MODE_FLAG_PHSYNC) ? 0 : 1;
201 	const int vsync_pol = (mode->flags & DRM_MODE_FLAG_PVSYNC) ? 0 : 1;
202 	const int data_enable_pol =
203 		(disp_info->bus_flags & DRM_BUS_FLAG_DE_HIGH) ? 0 : 1;
204 	const int clk_pol =
205 		(disp_info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE) ? 0 : 1;
206 
207 	clk_div = DIV_ROUND_CLOSEST_ULL(clk_get_rate(lcdc->clk_per),
208 					mode->clock * 1000);
209 	bpp = imx_lcdc_get_format(plane_state->fb->format->format);
210 
211 	writel(FIELD_PREP(IMX21LCDC_LPCR_PCD, clk_div - 1) |
212 	       FIELD_PREP(IMX21LCDC_LPCR_LPPOL, hsync_pol) |
213 	       FIELD_PREP(IMX21LCDC_LPCR_FLMPOL, vsync_pol) |
214 	       FIELD_PREP(IMX21LCDC_LPCR_OEPOL, data_enable_pol) |
215 	       FIELD_PREP(IMX21LCDC_LPCR_TFT, 1) |
216 	       FIELD_PREP(IMX21LCDC_LPCR_COLOR, 1) |
217 	       FIELD_PREP(IMX21LCDC_LPCR_PBSIZ, 3) |
218 	       FIELD_PREP(IMX21LCDC_LPCR_BPIX, bpp) |
219 	       FIELD_PREP(IMX21LCDC_LPCR_SCLKSEL, 1) |
220 	       FIELD_PREP(IMX21LCDC_LPCR_PIXPOL, 0) |
221 	       FIELD_PREP(IMX21LCDC_LPCR_CLKPOL, clk_pol),
222 	       lcdc->base + IMX21LCDC_LPCR);
223 
224 	/* 0px panning offset */
225 	writel(0x00000000, lcdc->base + IMX21LCDC_LPOR);
226 
227 	/* disable hardware cursor */
228 	writel(readl(lcdc->base + IMX21LCDC_LCPR) & ~(IMX21LCDC_LCPR_CC0 | IMX21LCDC_LCPR_CC1),
229 	       lcdc->base + IMX21LCDC_LCPR);
230 
231 	ret = clk_prepare_enable(lcdc->clk_ipg);
232 	if (ret) {
233 		dev_err(pipe->crtc.dev->dev, "Cannot enable ipg clock: %pe\n", ERR_PTR(ret));
234 		return;
235 	}
236 	ret = clk_prepare_enable(lcdc->clk_ahb);
237 	if (ret) {
238 		dev_err(pipe->crtc.dev->dev, "Cannot enable ahb clock: %pe\n", ERR_PTR(ret));
239 
240 		clk_disable_unprepare(lcdc->clk_ipg);
241 
242 		return;
243 	}
244 
245 	imx_lcdc_update_hw_registers(pipe, NULL, true);
246 
247 	/* Enable VBLANK Interrupt */
248 	writel(INTR_EOF, lcdc->base + IMX21LCDC_LIER);
249 }
250 
251 static void imx_lcdc_pipe_disable(struct drm_simple_display_pipe *pipe)
252 {
253 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
254 	struct drm_crtc *crtc = &lcdc->pipe.crtc;
255 	struct drm_pending_vblank_event *event;
256 
257 	clk_disable_unprepare(lcdc->clk_ahb);
258 	clk_disable_unprepare(lcdc->clk_ipg);
259 
260 	if (pipe->crtc.enabled)
261 		clk_disable_unprepare(lcdc->clk_per);
262 
263 	spin_lock_irq(&lcdc->drm.event_lock);
264 	event = crtc->state->event;
265 	if (event) {
266 		crtc->state->event = NULL;
267 		drm_crtc_send_vblank_event(crtc, event);
268 	}
269 	spin_unlock_irq(&lcdc->drm.event_lock);
270 
271 	/* Disable VBLANK Interrupt */
272 	writel(0, lcdc->base + IMX21LCDC_LIER);
273 }
274 
275 static int imx_lcdc_pipe_check(struct drm_simple_display_pipe *pipe,
276 			       struct drm_plane_state *plane_state,
277 			       struct drm_crtc_state *crtc_state)
278 {
279 	const struct drm_display_mode *mode = &crtc_state->mode;
280 	const struct drm_display_mode *old_mode = &pipe->crtc.state->mode;
281 
282 	if (mode->hdisplay < LCDC_MIN_XRES || mode->hdisplay > LCDC_MAX_XRES ||
283 	    mode->vdisplay < LCDC_MIN_YRES || mode->vdisplay > LCDC_MAX_YRES ||
284 	    mode->hdisplay % 0x10) { /* must be multiple of 16 */
285 		drm_err(pipe->crtc.dev, "unsupported display mode (%u x %u)\n",
286 			mode->hdisplay, mode->vdisplay);
287 		return -EINVAL;
288 	}
289 
290 	crtc_state->mode_changed =
291 		old_mode->hdisplay != mode->hdisplay ||
292 		old_mode->vdisplay != mode->vdisplay;
293 
294 	return 0;
295 }
296 
297 static void imx_lcdc_pipe_update(struct drm_simple_display_pipe *pipe,
298 				 struct drm_plane_state *old_state)
299 {
300 	struct drm_crtc *crtc = &pipe->crtc;
301 	struct drm_pending_vblank_event *event = crtc->state->event;
302 	struct drm_plane_state *new_state = pipe->plane.state;
303 	struct drm_framebuffer *fb = new_state->fb;
304 	struct drm_framebuffer *old_fb = old_state->fb;
305 	struct drm_crtc *old_crtc = old_state->crtc;
306 	bool mode_changed = false;
307 
308 	if (old_fb && old_fb->format != fb->format)
309 		mode_changed = true;
310 	else if (old_crtc != crtc)
311 		mode_changed = true;
312 
313 	imx_lcdc_update_hw_registers(pipe, old_state, mode_changed);
314 
315 	if (event) {
316 		crtc->state->event = NULL;
317 
318 		spin_lock_irq(&crtc->dev->event_lock);
319 
320 		if (crtc->state->active && drm_crtc_vblank_get(crtc) == 0)
321 			drm_crtc_arm_vblank_event(crtc, event);
322 		else
323 			drm_crtc_send_vblank_event(crtc, event);
324 
325 		spin_unlock_irq(&crtc->dev->event_lock);
326 	}
327 }
328 
329 static const struct drm_simple_display_pipe_funcs imx_lcdc_pipe_funcs = {
330 	.enable = imx_lcdc_pipe_enable,
331 	.disable = imx_lcdc_pipe_disable,
332 	.check = imx_lcdc_pipe_check,
333 	.update = imx_lcdc_pipe_update,
334 };
335 
336 static const struct drm_mode_config_funcs imx_lcdc_mode_config_funcs = {
337 	.fb_create = drm_gem_fb_create_with_dirty,
338 	.atomic_check = drm_atomic_helper_check,
339 	.atomic_commit = drm_atomic_helper_commit,
340 };
341 
342 static const struct drm_mode_config_helper_funcs imx_lcdc_mode_config_helpers = {
343 	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
344 };
345 
346 DEFINE_DRM_GEM_DMA_FOPS(imx_lcdc_drm_fops);
347 
348 static struct drm_driver imx_lcdc_drm_driver = {
349 	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
350 	.fops = &imx_lcdc_drm_fops,
351 	DRM_GEM_DMA_DRIVER_OPS_VMAP,
352 	DRM_FBDEV_DMA_DRIVER_OPS,
353 	.name = "imx-lcdc",
354 	.desc = "i.MX LCDC driver",
355 	.date = "20200716",
356 };
357 
358 static const struct of_device_id imx_lcdc_of_dev_id[] = {
359 	{
360 		.compatible = "fsl,imx21-lcdc",
361 	},
362 	{
363 		.compatible = "fsl,imx25-lcdc",
364 	},
365 	{ /* sentinel */ }
366 };
367 MODULE_DEVICE_TABLE(of, imx_lcdc_of_dev_id);
368 
369 static irqreturn_t imx_lcdc_irq_handler(int irq, void *arg)
370 {
371 	struct imx_lcdc *lcdc = arg;
372 	struct drm_crtc *crtc = &lcdc->pipe.crtc;
373 	unsigned int status;
374 
375 	status = readl(lcdc->base + IMX21LCDC_LISR);
376 
377 	if (status & INTR_EOF) {
378 		drm_crtc_handle_vblank(crtc);
379 		return IRQ_HANDLED;
380 	}
381 
382 	return IRQ_NONE;
383 }
384 
385 static int imx_lcdc_probe(struct platform_device *pdev)
386 {
387 	struct imx_lcdc *lcdc;
388 	struct drm_device *drm;
389 	struct drm_bridge *bridge;
390 	int irq;
391 	int ret;
392 	struct device *dev = &pdev->dev;
393 
394 	lcdc = devm_drm_dev_alloc(dev, &imx_lcdc_drm_driver,
395 				  struct imx_lcdc, drm);
396 	if (IS_ERR(lcdc))
397 		return PTR_ERR(lcdc);
398 
399 	drm = &lcdc->drm;
400 
401 	lcdc->base = devm_platform_ioremap_resource(pdev, 0);
402 	if (IS_ERR(lcdc->base))
403 		return dev_err_probe(dev, PTR_ERR(lcdc->base), "Cannot get IO memory\n");
404 
405 	bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
406 	if (IS_ERR(bridge))
407 		return dev_err_probe(dev, PTR_ERR(bridge), "Failed to find bridge\n");
408 
409 	/* Get Clocks */
410 	lcdc->clk_ipg = devm_clk_get(dev, "ipg");
411 	if (IS_ERR(lcdc->clk_ipg))
412 		return dev_err_probe(dev, PTR_ERR(lcdc->clk_ipg), "Failed to get %s clk\n", "ipg");
413 
414 	lcdc->clk_ahb = devm_clk_get(dev, "ahb");
415 	if (IS_ERR(lcdc->clk_ahb))
416 		return dev_err_probe(dev, PTR_ERR(lcdc->clk_ahb), "Failed to get %s clk\n", "ahb");
417 
418 	lcdc->clk_per = devm_clk_get(dev, "per");
419 	if (IS_ERR(lcdc->clk_per))
420 		return dev_err_probe(dev, PTR_ERR(lcdc->clk_per), "Failed to get %s clk\n", "per");
421 
422 	ret = dma_set_mask_and_coherent(drm->dev, DMA_BIT_MASK(32));
423 	if (ret)
424 		return dev_err_probe(dev, ret, "Cannot set DMA Mask\n");
425 
426 	/* Modeset init */
427 	ret = drmm_mode_config_init(drm);
428 	if (ret)
429 		return dev_err_probe(dev, ret, "Cannot initialize mode configuration structure\n");
430 
431 	/* CRTC, Plane, Encoder */
432 	ret = drm_simple_display_pipe_init(drm, &lcdc->pipe,
433 					   &imx_lcdc_pipe_funcs,
434 					   imx_lcdc_formats,
435 					   ARRAY_SIZE(imx_lcdc_formats), NULL, NULL);
436 	if (ret < 0)
437 		return dev_err_probe(drm->dev, ret, "Cannot setup simple display pipe\n");
438 
439 	ret = drm_vblank_init(drm, drm->mode_config.num_crtc);
440 	if (ret < 0)
441 		return dev_err_probe(drm->dev, ret, "Failed to initialize vblank\n");
442 
443 	ret = drm_bridge_attach(&lcdc->pipe.encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
444 	if (ret)
445 		return dev_err_probe(drm->dev, ret, "Cannot attach bridge\n");
446 
447 	lcdc->connector = drm_bridge_connector_init(drm, &lcdc->pipe.encoder);
448 	if (IS_ERR(lcdc->connector))
449 		return dev_err_probe(drm->dev, PTR_ERR(lcdc->connector), "Cannot init bridge connector\n");
450 
451 	drm_connector_attach_encoder(lcdc->connector, &lcdc->pipe.encoder);
452 
453 	/*
454 	 * The LCDC controller does not have an enable bit. The
455 	 * controller starts directly when the clocks are enabled.
456 	 * If the clocks are enabled when the controller is not yet
457 	 * programmed with proper register values (enabled at the
458 	 * bootloader, for example) then it just goes into some undefined
459 	 * state.
460 	 * To avoid this issue, let's enable and disable LCDC IPG,
461 	 * PER and AHB clock so that we force some kind of 'reset'
462 	 * to the LCDC block.
463 	 */
464 
465 	ret = clk_prepare_enable(lcdc->clk_ipg);
466 	if (ret)
467 		return dev_err_probe(dev, ret, "Cannot enable ipg clock\n");
468 	clk_disable_unprepare(lcdc->clk_ipg);
469 
470 	ret = clk_prepare_enable(lcdc->clk_per);
471 	if (ret)
472 		return dev_err_probe(dev, ret, "Cannot enable per clock\n");
473 	clk_disable_unprepare(lcdc->clk_per);
474 
475 	ret = clk_prepare_enable(lcdc->clk_ahb);
476 	if (ret)
477 		return dev_err_probe(dev, ret, "Cannot enable ahb clock\n");
478 	clk_disable_unprepare(lcdc->clk_ahb);
479 
480 	drm->mode_config.min_width = LCDC_MIN_XRES;
481 	drm->mode_config.max_width = LCDC_MAX_XRES;
482 	drm->mode_config.min_height = LCDC_MIN_YRES;
483 	drm->mode_config.max_height = LCDC_MAX_YRES;
484 	drm->mode_config.preferred_depth = 16;
485 	drm->mode_config.funcs = &imx_lcdc_mode_config_funcs;
486 	drm->mode_config.helper_private = &imx_lcdc_mode_config_helpers;
487 
488 	drm_mode_config_reset(drm);
489 
490 	irq = platform_get_irq(pdev, 0);
491 	if (irq < 0) {
492 		ret = irq;
493 		return ret;
494 	}
495 
496 	ret = devm_request_irq(dev, irq, imx_lcdc_irq_handler, 0, "imx-lcdc", lcdc);
497 	if (ret < 0)
498 		return dev_err_probe(drm->dev, ret, "Failed to install IRQ handler\n");
499 
500 	platform_set_drvdata(pdev, drm);
501 
502 	ret = drm_dev_register(&lcdc->drm, 0);
503 	if (ret)
504 		return dev_err_probe(dev, ret, "Cannot register device\n");
505 
506 	drm_client_setup(drm, NULL);
507 
508 	return 0;
509 }
510 
511 static void imx_lcdc_remove(struct platform_device *pdev)
512 {
513 	struct drm_device *drm = platform_get_drvdata(pdev);
514 
515 	drm_dev_unregister(drm);
516 	drm_atomic_helper_shutdown(drm);
517 }
518 
519 static void imx_lcdc_shutdown(struct platform_device *pdev)
520 {
521 	drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
522 }
523 
524 static struct platform_driver imx_lcdc_driver = {
525 	.driver = {
526 		.name = "imx-lcdc",
527 		.of_match_table = imx_lcdc_of_dev_id,
528 	},
529 	.probe = imx_lcdc_probe,
530 	.remove_new = imx_lcdc_remove,
531 	.shutdown = imx_lcdc_shutdown,
532 };
533 module_platform_driver(imx_lcdc_driver);
534 
535 MODULE_AUTHOR("Marian Cichy <M.Cichy@pengutronix.de>");
536 MODULE_DESCRIPTION("Freescale i.MX LCDC driver");
537 MODULE_LICENSE("GPL");
538