xref: /linux/drivers/gpu/drm/imx/lcdc/imx-lcdc.c (revision f6e8dc9edf963dbc99085e54f6ced6da9daa6100)
1 // SPDX-License-Identifier: GPL-2.0-only
2 // SPDX-FileCopyrightText: 2020 Marian Cichy <M.Cichy@pengutronix.de>
3 
4 #include <drm/clients/drm_client_setup.h>
5 #include <drm/drm_bridge.h>
6 #include <drm/drm_bridge_connector.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_print.h>
18 #include <drm/drm_probe_helper.h>
19 #include <drm/drm_simple_kms_helper.h>
20 #include <drm/drm_vblank.h>
21 #include <linux/bitfield.h>
22 #include <linux/clk.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/mod_devicetable.h>
25 #include <linux/module.h>
26 #include <linux/platform_device.h>
27 
28 #define IMX21LCDC_LSSAR         0x0000 /* LCDC Screen Start Address Register */
29 #define IMX21LCDC_LSR           0x0004 /* LCDC Size Register */
30 #define IMX21LCDC_LVPWR         0x0008 /* LCDC Virtual Page Width Register */
31 #define IMX21LCDC_LCPR          0x000C /* LCDC Cursor Position Register */
32 #define IMX21LCDC_LCWHB         0x0010 /* LCDC Cursor Width Height and Blink Register*/
33 #define IMX21LCDC_LCCMR         0x0014 /* LCDC Color Cursor Mapping Register */
34 #define IMX21LCDC_LPCR          0x0018 /* LCDC Panel Configuration Register */
35 #define IMX21LCDC_LHCR          0x001C /* LCDC Horizontal Configuration Register */
36 #define IMX21LCDC_LVCR          0x0020 /* LCDC Vertical Configuration Register */
37 #define IMX21LCDC_LPOR          0x0024 /* LCDC Panning Offset Register */
38 #define IMX21LCDC_LSCR          0x0028 /* LCDC Sharp Configuration Register */
39 #define IMX21LCDC_LPCCR         0x002C /* LCDC PWM Contrast Control Register */
40 #define IMX21LCDC_LDCR          0x0030 /* LCDC DMA Control Register */
41 #define IMX21LCDC_LRMCR         0x0034 /* LCDC Refresh Mode Control Register */
42 #define IMX21LCDC_LICR          0x0038 /* LCDC Interrupt Configuration Register */
43 #define IMX21LCDC_LIER          0x003C /* LCDC Interrupt Enable Register */
44 #define IMX21LCDC_LISR          0x0040 /* LCDC Interrupt Status Register */
45 #define IMX21LCDC_LGWSAR        0x0050 /* LCDC Graphic Window Start Address Register */
46 #define IMX21LCDC_LGWSR         0x0054 /* LCDC Graph Window Size Register */
47 #define IMX21LCDC_LGWVPWR       0x0058 /* LCDC Graphic Window Virtual Page Width Register */
48 #define IMX21LCDC_LGWPOR        0x005C /* LCDC Graphic Window Panning Offset Register */
49 #define IMX21LCDC_LGWPR         0x0060 /* LCDC Graphic Window Position Register */
50 #define IMX21LCDC_LGWCR         0x0064 /* LCDC Graphic Window Control Register */
51 #define IMX21LCDC_LGWDCR        0x0068 /* LCDC Graphic Window DMA Control Register */
52 #define IMX21LCDC_LAUSCR        0x0080 /* LCDC AUS Mode Control Register */
53 #define IMX21LCDC_LAUSCCR       0x0084 /* LCDC AUS Mode Cursor Control Register */
54 #define IMX21LCDC_BGLUT         0x0800 /* Background Lookup Table */
55 #define IMX21LCDC_GWLUT         0x0C00 /* Graphic Window Lookup Table */
56 
57 #define IMX21LCDC_LCPR_CC0 BIT(30) /* Cursor Control Bit 0 */
58 #define IMX21LCDC_LCPR_CC1 BIT(31) /* Cursor Control Bit 1 */
59 
60 /* Values HSYNC, VSYNC and Framesize Register */
61 #define IMX21LCDC_LHCR_HWIDTH		GENMASK(31, 26)
62 #define IMX21LCDC_LHCR_HFPORCH		GENMASK(15, 8)		/* H_WAIT_1 in the i.MX25 Reference manual */
63 #define IMX21LCDC_LHCR_HBPORCH		GENMASK(7, 0)		/* H_WAIT_2 in the i.MX25 Reference manual */
64 
65 #define IMX21LCDC_LVCR_VWIDTH		GENMASK(31, 26)
66 #define IMX21LCDC_LVCR_VFPORCH		GENMASK(15, 8)		/* V_WAIT_1 in the i.MX25 Reference manual */
67 #define IMX21LCDC_LVCR_VBPORCH		GENMASK(7, 0)		/* V_WAIT_2 in the i.MX25 Reference manual */
68 
69 #define IMX21LCDC_LSR_XMAX		GENMASK(25, 20)
70 #define IMX21LCDC_LSR_YMAX		GENMASK(9, 0)
71 
72 /* Values for LPCR Register */
73 #define IMX21LCDC_LPCR_PCD		GENMASK(5, 0)
74 #define IMX21LCDC_LPCR_SHARP		BIT(6)
75 #define IMX21LCDC_LPCR_SCLKSEL		BIT(7)
76 #define IMX21LCDC_LPCR_ACD		GENMASK(14, 8)
77 #define IMX21LCDC_LPCR_ACDSEL		BIT(15)
78 #define IMX21LCDC_LPCR_REV_VS		BIT(16)
79 #define IMX21LCDC_LPCR_SWAP_SEL		BIT(17)
80 #define IMX21LCDC_LPCR_END_SEL		BIT(18)
81 #define IMX21LCDC_LPCR_SCLKIDLE		BIT(19)
82 #define IMX21LCDC_LPCR_OEPOL		BIT(20)
83 #define IMX21LCDC_LPCR_CLKPOL		BIT(21)
84 #define IMX21LCDC_LPCR_LPPOL		BIT(22)
85 #define IMX21LCDC_LPCR_FLMPOL		BIT(23)
86 #define IMX21LCDC_LPCR_PIXPOL		BIT(24)
87 #define IMX21LCDC_LPCR_BPIX		GENMASK(27, 25)
88 #define IMX21LCDC_LPCR_PBSIZ		GENMASK(29, 28)
89 #define IMX21LCDC_LPCR_COLOR		BIT(30)
90 #define IMX21LCDC_LPCR_TFT		BIT(31)
91 
92 #define INTR_EOF BIT(1) /* VBLANK Interrupt Bit */
93 
94 #define BPP_RGB565	0x05
95 #define BPP_XRGB8888	0x07
96 
97 #define LCDC_MIN_XRES 64
98 #define LCDC_MIN_YRES 64
99 
100 #define LCDC_MAX_XRES 1024
101 #define LCDC_MAX_YRES 1024
102 
103 struct imx_lcdc {
104 	struct drm_device drm;
105 	struct drm_simple_display_pipe pipe;
106 	struct drm_connector *connector;
107 	void __iomem *base;
108 
109 	struct clk *clk_ipg;
110 	struct clk *clk_ahb;
111 	struct clk *clk_per;
112 };
113 
114 static const u32 imx_lcdc_formats[] = {
115 	DRM_FORMAT_RGB565, DRM_FORMAT_XRGB8888,
116 };
117 
118 static inline struct imx_lcdc *imx_lcdc_from_drmdev(struct drm_device *drm)
119 {
120 	return container_of(drm, struct imx_lcdc, drm);
121 }
122 
123 static unsigned int imx_lcdc_get_format(unsigned int drm_format)
124 {
125 	switch (drm_format) {
126 	default:
127 		DRM_WARN("Format not supported - fallback to XRGB8888\n");
128 		fallthrough;
129 
130 	case DRM_FORMAT_XRGB8888:
131 		return BPP_XRGB8888;
132 
133 	case DRM_FORMAT_RGB565:
134 		return BPP_RGB565;
135 	}
136 }
137 
138 static void imx_lcdc_update_hw_registers(struct drm_simple_display_pipe *pipe,
139 					 struct drm_plane_state *old_state,
140 					 bool mode_set)
141 {
142 	struct drm_crtc *crtc = &pipe->crtc;
143 	struct drm_plane_state *new_state = pipe->plane.state;
144 	struct drm_framebuffer *fb = new_state->fb;
145 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
146 	u32 lpcr, lvcr, lhcr;
147 	u32 framesize;
148 	dma_addr_t addr;
149 
150 	addr = drm_fb_dma_get_gem_addr(fb, new_state, 0);
151 	/* The LSSAR register specifies the LCD screen start address (SSA). */
152 	writel(addr, lcdc->base + IMX21LCDC_LSSAR);
153 
154 	if (!mode_set)
155 		return;
156 
157 	/* Disable PER clock to make register write possible */
158 	if (old_state && old_state->crtc && old_state->crtc->enabled)
159 		clk_disable_unprepare(lcdc->clk_per);
160 
161 	/* Framesize */
162 	framesize = FIELD_PREP(IMX21LCDC_LSR_XMAX, crtc->mode.hdisplay >> 4) |
163 		FIELD_PREP(IMX21LCDC_LSR_YMAX, crtc->mode.vdisplay);
164 	writel(framesize, lcdc->base + IMX21LCDC_LSR);
165 
166 	/* HSYNC */
167 	lhcr = FIELD_PREP(IMX21LCDC_LHCR_HFPORCH, crtc->mode.hsync_start - crtc->mode.hdisplay - 1) |
168 		FIELD_PREP(IMX21LCDC_LHCR_HWIDTH, crtc->mode.hsync_end - crtc->mode.hsync_start - 1) |
169 		FIELD_PREP(IMX21LCDC_LHCR_HBPORCH, crtc->mode.htotal - crtc->mode.hsync_end - 3);
170 	writel(lhcr, lcdc->base + IMX21LCDC_LHCR);
171 
172 	/* VSYNC */
173 	lvcr = FIELD_PREP(IMX21LCDC_LVCR_VFPORCH, crtc->mode.vsync_start - crtc->mode.vdisplay) |
174 		FIELD_PREP(IMX21LCDC_LVCR_VWIDTH, crtc->mode.vsync_end - crtc->mode.vsync_start) |
175 		FIELD_PREP(IMX21LCDC_LVCR_VBPORCH, crtc->mode.vtotal - crtc->mode.vsync_end);
176 	writel(lvcr, lcdc->base + IMX21LCDC_LVCR);
177 
178 	lpcr = readl(lcdc->base + IMX21LCDC_LPCR);
179 	lpcr &= ~IMX21LCDC_LPCR_BPIX;
180 	lpcr |= FIELD_PREP(IMX21LCDC_LPCR_BPIX, imx_lcdc_get_format(fb->format->format));
181 	writel(lpcr, lcdc->base + IMX21LCDC_LPCR);
182 
183 	/* Virtual Page Width */
184 	writel(new_state->fb->pitches[0] / 4, lcdc->base + IMX21LCDC_LVPWR);
185 
186 	/* Enable PER clock */
187 	if (new_state->crtc->enabled)
188 		clk_prepare_enable(lcdc->clk_per);
189 }
190 
191 static void imx_lcdc_pipe_enable(struct drm_simple_display_pipe *pipe,
192 				 struct drm_crtc_state *crtc_state,
193 				 struct drm_plane_state *plane_state)
194 {
195 	int ret;
196 	int clk_div;
197 	int bpp;
198 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
199 	struct drm_display_mode *mode = &pipe->crtc.mode;
200 	struct drm_display_info *disp_info = &lcdc->connector->display_info;
201 	const int hsync_pol = (mode->flags & DRM_MODE_FLAG_PHSYNC) ? 0 : 1;
202 	const int vsync_pol = (mode->flags & DRM_MODE_FLAG_PVSYNC) ? 0 : 1;
203 	const int data_enable_pol =
204 		(disp_info->bus_flags & DRM_BUS_FLAG_DE_HIGH) ? 0 : 1;
205 	const int clk_pol =
206 		(disp_info->bus_flags & DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE) ? 0 : 1;
207 
208 	clk_div = DIV_ROUND_CLOSEST_ULL(clk_get_rate(lcdc->clk_per),
209 					mode->clock * 1000);
210 	bpp = imx_lcdc_get_format(plane_state->fb->format->format);
211 
212 	writel(FIELD_PREP(IMX21LCDC_LPCR_PCD, clk_div - 1) |
213 	       FIELD_PREP(IMX21LCDC_LPCR_LPPOL, hsync_pol) |
214 	       FIELD_PREP(IMX21LCDC_LPCR_FLMPOL, vsync_pol) |
215 	       FIELD_PREP(IMX21LCDC_LPCR_OEPOL, data_enable_pol) |
216 	       FIELD_PREP(IMX21LCDC_LPCR_TFT, 1) |
217 	       FIELD_PREP(IMX21LCDC_LPCR_COLOR, 1) |
218 	       FIELD_PREP(IMX21LCDC_LPCR_PBSIZ, 3) |
219 	       FIELD_PREP(IMX21LCDC_LPCR_BPIX, bpp) |
220 	       FIELD_PREP(IMX21LCDC_LPCR_SCLKSEL, 1) |
221 	       FIELD_PREP(IMX21LCDC_LPCR_PIXPOL, 0) |
222 	       FIELD_PREP(IMX21LCDC_LPCR_CLKPOL, clk_pol),
223 	       lcdc->base + IMX21LCDC_LPCR);
224 
225 	/* 0px panning offset */
226 	writel(0x00000000, lcdc->base + IMX21LCDC_LPOR);
227 
228 	/* disable hardware cursor */
229 	writel(readl(lcdc->base + IMX21LCDC_LCPR) & ~(IMX21LCDC_LCPR_CC0 | IMX21LCDC_LCPR_CC1),
230 	       lcdc->base + IMX21LCDC_LCPR);
231 
232 	ret = clk_prepare_enable(lcdc->clk_ipg);
233 	if (ret) {
234 		dev_err(pipe->crtc.dev->dev, "Cannot enable ipg clock: %pe\n", ERR_PTR(ret));
235 		return;
236 	}
237 	ret = clk_prepare_enable(lcdc->clk_ahb);
238 	if (ret) {
239 		dev_err(pipe->crtc.dev->dev, "Cannot enable ahb clock: %pe\n", ERR_PTR(ret));
240 
241 		clk_disable_unprepare(lcdc->clk_ipg);
242 
243 		return;
244 	}
245 
246 	imx_lcdc_update_hw_registers(pipe, NULL, true);
247 
248 	/* Enable VBLANK Interrupt */
249 	writel(INTR_EOF, lcdc->base + IMX21LCDC_LIER);
250 }
251 
252 static void imx_lcdc_pipe_disable(struct drm_simple_display_pipe *pipe)
253 {
254 	struct imx_lcdc *lcdc = imx_lcdc_from_drmdev(pipe->crtc.dev);
255 	struct drm_crtc *crtc = &lcdc->pipe.crtc;
256 	struct drm_pending_vblank_event *event;
257 
258 	clk_disable_unprepare(lcdc->clk_ahb);
259 	clk_disable_unprepare(lcdc->clk_ipg);
260 
261 	if (pipe->crtc.enabled)
262 		clk_disable_unprepare(lcdc->clk_per);
263 
264 	spin_lock_irq(&lcdc->drm.event_lock);
265 	event = crtc->state->event;
266 	if (event) {
267 		crtc->state->event = NULL;
268 		drm_crtc_send_vblank_event(crtc, event);
269 	}
270 	spin_unlock_irq(&lcdc->drm.event_lock);
271 
272 	/* Disable VBLANK Interrupt */
273 	writel(0, lcdc->base + IMX21LCDC_LIER);
274 }
275 
276 static int imx_lcdc_pipe_check(struct drm_simple_display_pipe *pipe,
277 			       struct drm_plane_state *plane_state,
278 			       struct drm_crtc_state *crtc_state)
279 {
280 	const struct drm_display_mode *mode = &crtc_state->mode;
281 	const struct drm_display_mode *old_mode = &pipe->crtc.state->mode;
282 
283 	if (mode->hdisplay < LCDC_MIN_XRES || mode->hdisplay > LCDC_MAX_XRES ||
284 	    mode->vdisplay < LCDC_MIN_YRES || mode->vdisplay > LCDC_MAX_YRES ||
285 	    mode->hdisplay % 0x10) { /* must be multiple of 16 */
286 		drm_err(pipe->crtc.dev, "unsupported display mode (%u x %u)\n",
287 			mode->hdisplay, mode->vdisplay);
288 		return -EINVAL;
289 	}
290 
291 	crtc_state->mode_changed =
292 		old_mode->hdisplay != mode->hdisplay ||
293 		old_mode->vdisplay != mode->vdisplay;
294 
295 	return 0;
296 }
297 
298 static void imx_lcdc_pipe_update(struct drm_simple_display_pipe *pipe,
299 				 struct drm_plane_state *old_state)
300 {
301 	struct drm_crtc *crtc = &pipe->crtc;
302 	struct drm_pending_vblank_event *event = crtc->state->event;
303 	struct drm_plane_state *new_state = pipe->plane.state;
304 	struct drm_framebuffer *fb = new_state->fb;
305 	struct drm_framebuffer *old_fb = old_state->fb;
306 	struct drm_crtc *old_crtc = old_state->crtc;
307 	bool mode_changed = false;
308 
309 	if (old_fb && old_fb->format != fb->format)
310 		mode_changed = true;
311 	else if (old_crtc != crtc)
312 		mode_changed = true;
313 
314 	imx_lcdc_update_hw_registers(pipe, old_state, mode_changed);
315 
316 	if (event) {
317 		crtc->state->event = NULL;
318 
319 		spin_lock_irq(&crtc->dev->event_lock);
320 
321 		if (crtc->state->active && drm_crtc_vblank_get(crtc) == 0)
322 			drm_crtc_arm_vblank_event(crtc, event);
323 		else
324 			drm_crtc_send_vblank_event(crtc, event);
325 
326 		spin_unlock_irq(&crtc->dev->event_lock);
327 	}
328 }
329 
330 static const struct drm_simple_display_pipe_funcs imx_lcdc_pipe_funcs = {
331 	.enable = imx_lcdc_pipe_enable,
332 	.disable = imx_lcdc_pipe_disable,
333 	.check = imx_lcdc_pipe_check,
334 	.update = imx_lcdc_pipe_update,
335 };
336 
337 static const struct drm_mode_config_funcs imx_lcdc_mode_config_funcs = {
338 	.fb_create = drm_gem_fb_create_with_dirty,
339 	.atomic_check = drm_atomic_helper_check,
340 	.atomic_commit = drm_atomic_helper_commit,
341 };
342 
343 static const struct drm_mode_config_helper_funcs imx_lcdc_mode_config_helpers = {
344 	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
345 };
346 
347 DEFINE_DRM_GEM_DMA_FOPS(imx_lcdc_drm_fops);
348 
349 static struct drm_driver imx_lcdc_drm_driver = {
350 	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
351 	.fops = &imx_lcdc_drm_fops,
352 	DRM_GEM_DMA_DRIVER_OPS_VMAP,
353 	DRM_FBDEV_DMA_DRIVER_OPS,
354 	.name = "imx-lcdc",
355 	.desc = "i.MX LCDC driver",
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 = 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