xref: /kernel/linux/linux-6.6/drivers/gpu/drm/tegra/rgb.c (revision 62306a36)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2012 Avionic Design GmbH
4 * Copyright (C) 2012 NVIDIA CORPORATION.  All rights reserved.
5 */
6
7#include <linux/clk.h>
8#include <linux/of.h>
9
10#include <drm/drm_atomic_helper.h>
11#include <drm/drm_bridge_connector.h>
12#include <drm/drm_simple_kms_helper.h>
13
14#include "drm.h"
15#include "dc.h"
16
17struct tegra_rgb {
18	struct tegra_output output;
19	struct tegra_dc *dc;
20
21	struct clk *pll_d_out0;
22	struct clk *pll_d2_out0;
23	struct clk *clk_parent;
24	struct clk *clk;
25};
26
27static inline struct tegra_rgb *to_rgb(struct tegra_output *output)
28{
29	return container_of(output, struct tegra_rgb, output);
30}
31
32struct reg_entry {
33	unsigned long offset;
34	unsigned long value;
35};
36
37static const struct reg_entry rgb_enable[] = {
38	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x00000000 },
39	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x00000000 },
40	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x00000000 },
41	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x00000000 },
42	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
43	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x01000000 },
44	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
45	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
46	{ DC_COM_PIN_OUTPUT_DATA(0),     0x00000000 },
47	{ DC_COM_PIN_OUTPUT_DATA(1),     0x00000000 },
48	{ DC_COM_PIN_OUTPUT_DATA(2),     0x00000000 },
49	{ DC_COM_PIN_OUTPUT_DATA(3),     0x00000000 },
50	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
51	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
52	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
53	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
54	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00210222 },
55	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00002200 },
56	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00020000 },
57};
58
59static const struct reg_entry rgb_disable[] = {
60	{ DC_COM_PIN_OUTPUT_SELECT(6),   0x00000000 },
61	{ DC_COM_PIN_OUTPUT_SELECT(5),   0x00000000 },
62	{ DC_COM_PIN_OUTPUT_SELECT(4),   0x00000000 },
63	{ DC_COM_PIN_OUTPUT_SELECT(3),   0x00000000 },
64	{ DC_COM_PIN_OUTPUT_SELECT(2),   0x00000000 },
65	{ DC_COM_PIN_OUTPUT_SELECT(1),   0x00000000 },
66	{ DC_COM_PIN_OUTPUT_SELECT(0),   0x00000000 },
67	{ DC_COM_PIN_OUTPUT_DATA(3),     0xaaaaaaaa },
68	{ DC_COM_PIN_OUTPUT_DATA(2),     0xaaaaaaaa },
69	{ DC_COM_PIN_OUTPUT_DATA(1),     0xaaaaaaaa },
70	{ DC_COM_PIN_OUTPUT_DATA(0),     0xaaaaaaaa },
71	{ DC_COM_PIN_OUTPUT_POLARITY(3), 0x00000000 },
72	{ DC_COM_PIN_OUTPUT_POLARITY(2), 0x00000000 },
73	{ DC_COM_PIN_OUTPUT_POLARITY(1), 0x00000000 },
74	{ DC_COM_PIN_OUTPUT_POLARITY(0), 0x00000000 },
75	{ DC_COM_PIN_OUTPUT_ENABLE(3),   0x55555555 },
76	{ DC_COM_PIN_OUTPUT_ENABLE(2),   0x55555555 },
77	{ DC_COM_PIN_OUTPUT_ENABLE(1),   0x55150005 },
78	{ DC_COM_PIN_OUTPUT_ENABLE(0),   0x55555555 },
79};
80
81static void tegra_dc_write_regs(struct tegra_dc *dc,
82				const struct reg_entry *table,
83				unsigned int num)
84{
85	unsigned int i;
86
87	for (i = 0; i < num; i++)
88		tegra_dc_writel(dc, table[i].value, table[i].offset);
89}
90
91static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
92{
93	struct tegra_output *output = encoder_to_output(encoder);
94	struct tegra_rgb *rgb = to_rgb(output);
95
96	tegra_dc_write_regs(rgb->dc, rgb_disable, ARRAY_SIZE(rgb_disable));
97	tegra_dc_commit(rgb->dc);
98}
99
100static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
101{
102	struct tegra_output *output = encoder_to_output(encoder);
103	struct tegra_rgb *rgb = to_rgb(output);
104	u32 value;
105
106	tegra_dc_write_regs(rgb->dc, rgb_enable, ARRAY_SIZE(rgb_enable));
107
108	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
109	tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);
110
111	/* XXX: parameterize? */
112	value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
113	value &= ~LVS_OUTPUT_POLARITY_LOW;
114	value &= ~LHS_OUTPUT_POLARITY_LOW;
115	tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));
116
117	/* XXX: parameterize? */
118	value = DISP_DATA_FORMAT_DF1P1C | DISP_ALIGNMENT_MSB |
119		DISP_ORDER_RED_BLUE;
120	tegra_dc_writel(rgb->dc, value, DC_DISP_DISP_INTERFACE_CONTROL);
121
122	tegra_dc_commit(rgb->dc);
123}
124
125static bool tegra_rgb_pll_rate_change_allowed(struct tegra_rgb *rgb)
126{
127	if (!rgb->pll_d2_out0)
128		return false;
129
130	if (!clk_is_match(rgb->clk_parent, rgb->pll_d_out0) &&
131	    !clk_is_match(rgb->clk_parent, rgb->pll_d2_out0))
132		return false;
133
134	return true;
135}
136
137static int
138tegra_rgb_encoder_atomic_check(struct drm_encoder *encoder,
139			       struct drm_crtc_state *crtc_state,
140			       struct drm_connector_state *conn_state)
141{
142	struct tegra_output *output = encoder_to_output(encoder);
143	struct tegra_dc *dc = to_tegra_dc(conn_state->crtc);
144	unsigned long pclk = crtc_state->mode.clock * 1000;
145	struct tegra_rgb *rgb = to_rgb(output);
146	unsigned int div;
147	int err;
148
149	/*
150	 * We may not want to change the frequency of the parent clock, since
151	 * it may be a parent for other peripherals. This is due to the fact
152	 * that on Tegra20 there's only a single clock dedicated to display
153	 * (pll_d_out0), whereas later generations have a second one that can
154	 * be used to independently drive a second output (pll_d2_out0).
155	 *
156	 * As a way to support multiple outputs on Tegra20 as well, pll_p is
157	 * typically used as the parent clock for the display controllers.
158	 * But this comes at a cost: pll_p is the parent of several other
159	 * peripherals, so its frequency shouldn't change out of the blue.
160	 *
161	 * The best we can do at this point is to use the shift clock divider
162	 * and hope that the desired frequency can be matched (or at least
163	 * matched sufficiently close that the panel will still work).
164	 */
165	if (tegra_rgb_pll_rate_change_allowed(rgb)) {
166		/*
167		 * Set display controller clock to x2 of PCLK in order to
168		 * produce higher resolution pulse positions.
169		 */
170		div = 2;
171		pclk *= 2;
172	} else {
173		div = ((clk_get_rate(rgb->clk) * 2) / pclk) - 2;
174		pclk = 0;
175	}
176
177	err = tegra_dc_state_setup_clock(dc, crtc_state, rgb->clk_parent,
178					 pclk, div);
179	if (err < 0) {
180		dev_err(output->dev, "failed to setup CRTC state: %d\n", err);
181		return err;
182	}
183
184	return err;
185}
186
187static const struct drm_encoder_helper_funcs tegra_rgb_encoder_helper_funcs = {
188	.disable = tegra_rgb_encoder_disable,
189	.enable = tegra_rgb_encoder_enable,
190	.atomic_check = tegra_rgb_encoder_atomic_check,
191};
192
193int tegra_dc_rgb_probe(struct tegra_dc *dc)
194{
195	struct device_node *np;
196	struct tegra_rgb *rgb;
197	int err;
198
199	np = of_get_child_by_name(dc->dev->of_node, "rgb");
200	if (!np || !of_device_is_available(np))
201		return -ENODEV;
202
203	rgb = devm_kzalloc(dc->dev, sizeof(*rgb), GFP_KERNEL);
204	if (!rgb)
205		return -ENOMEM;
206
207	rgb->output.dev = dc->dev;
208	rgb->output.of_node = np;
209	rgb->dc = dc;
210
211	err = tegra_output_probe(&rgb->output);
212	if (err < 0)
213		return err;
214
215	rgb->clk = devm_clk_get(dc->dev, NULL);
216	if (IS_ERR(rgb->clk)) {
217		dev_err(dc->dev, "failed to get clock\n");
218		err = PTR_ERR(rgb->clk);
219		goto remove;
220	}
221
222	rgb->clk_parent = devm_clk_get(dc->dev, "parent");
223	if (IS_ERR(rgb->clk_parent)) {
224		dev_err(dc->dev, "failed to get parent clock\n");
225		err = PTR_ERR(rgb->clk_parent);
226		goto remove;
227	}
228
229	err = clk_set_parent(rgb->clk, rgb->clk_parent);
230	if (err < 0) {
231		dev_err(dc->dev, "failed to set parent clock: %d\n", err);
232		goto remove;
233	}
234
235	rgb->pll_d_out0 = clk_get_sys(NULL, "pll_d_out0");
236	if (IS_ERR(rgb->pll_d_out0)) {
237		err = PTR_ERR(rgb->pll_d_out0);
238		dev_err(dc->dev, "failed to get pll_d_out0: %d\n", err);
239		goto remove;
240	}
241
242	if (dc->soc->has_pll_d2_out0) {
243		rgb->pll_d2_out0 = clk_get_sys(NULL, "pll_d2_out0");
244		if (IS_ERR(rgb->pll_d2_out0)) {
245			err = PTR_ERR(rgb->pll_d2_out0);
246			dev_err(dc->dev, "failed to get pll_d2_out0: %d\n", err);
247			goto put_pll;
248		}
249	}
250
251	dc->rgb = &rgb->output;
252
253	return 0;
254
255put_pll:
256	clk_put(rgb->pll_d_out0);
257remove:
258	tegra_output_remove(&rgb->output);
259	return err;
260}
261
262void tegra_dc_rgb_remove(struct tegra_dc *dc)
263{
264	struct tegra_rgb *rgb;
265
266	if (!dc->rgb)
267		return;
268
269	rgb = to_rgb(dc->rgb);
270	clk_put(rgb->pll_d2_out0);
271	clk_put(rgb->pll_d_out0);
272
273	tegra_output_remove(dc->rgb);
274	dc->rgb = NULL;
275}
276
277int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
278{
279	struct tegra_output *output = dc->rgb;
280	struct drm_connector *connector;
281	int err;
282
283	if (!dc->rgb)
284		return -ENODEV;
285
286	drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS);
287	drm_encoder_helper_add(&output->encoder,
288			       &tegra_rgb_encoder_helper_funcs);
289
290	/*
291	 * Wrap directly-connected panel into DRM bridge in order to let
292	 * DRM core to handle panel for us.
293	 */
294	if (output->panel) {
295		output->bridge = devm_drm_panel_bridge_add(output->dev,
296							   output->panel);
297		if (IS_ERR(output->bridge)) {
298			dev_err(output->dev,
299				"failed to wrap panel into bridge: %pe\n",
300				output->bridge);
301			return PTR_ERR(output->bridge);
302		}
303
304		output->panel = NULL;
305	}
306
307	/*
308	 * Tegra devices that have LVDS panel utilize LVDS encoder bridge
309	 * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that
310	 * go to display panel's receiver.
311	 *
312	 * Encoder usually have a power-down control which needs to be enabled
313	 * in order to transmit data to the panel.  Historically devices that
314	 * use an older device-tree version didn't model the bridge, assuming
315	 * that encoder is turned ON by default, while today's DRM allows us
316	 * to model LVDS encoder properly.
317	 *
318	 * Newer device-trees utilize LVDS encoder bridge, which provides
319	 * us with a connector and handles the display panel.
320	 *
321	 * For older device-trees we wrapped panel into the panel-bridge.
322	 */
323	if (output->bridge) {
324		err = drm_bridge_attach(&output->encoder, output->bridge,
325					NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
326		if (err)
327			return err;
328
329		connector = drm_bridge_connector_init(drm, &output->encoder);
330		if (IS_ERR(connector)) {
331			dev_err(output->dev,
332				"failed to initialize bridge connector: %pe\n",
333				connector);
334			return PTR_ERR(connector);
335		}
336
337		drm_connector_attach_encoder(connector, &output->encoder);
338	}
339
340	err = tegra_output_init(drm, output);
341	if (err < 0) {
342		dev_err(output->dev, "failed to initialize output: %d\n", err);
343		return err;
344	}
345
346	/*
347	 * Other outputs can be attached to either display controller. The RGB
348	 * outputs are an exception and work only with their parent display
349	 * controller.
350	 */
351	output->encoder.possible_crtcs = drm_crtc_mask(&dc->base);
352
353	return 0;
354}
355
356int tegra_dc_rgb_exit(struct tegra_dc *dc)
357{
358	if (dc->rgb)
359		tegra_output_exit(dc->rgb);
360
361	return 0;
362}
363