[go: nahoru, domu]
1/*
2 * Copyright (C) 2012 Russell King
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Armada 510 (aka Dove) variant support
9 */
10#include <linux/clk.h>
11#include <linux/io.h>
12#include <drm/drmP.h>
13#include <drm/drm_crtc_helper.h>
14#include "armada_crtc.h"
15#include "armada_drm.h"
16#include "armada_hw.h"
17
18static int armada510_crtc_init(struct armada_crtc *dcrtc, struct device *dev)
19{
20	struct clk *clk;
21
22	clk = devm_clk_get(dev, "ext_ref_clk1");
23	if (IS_ERR(clk))
24		return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER : PTR_ERR(clk);
25
26	dcrtc->extclk[0] = clk;
27
28	/* Lower the watermark so to eliminate jitter at higher bandwidths */
29	armada_updatel(0x20, (1 << 11) | 0xff, dcrtc->base + LCD_CFG_RDREG4F);
30
31	return 0;
32}
33
34/*
35 * Armada510 specific SCLK register selection.
36 * This gets called with sclk = NULL to test whether the mode is
37 * supportable, and again with sclk != NULL to set the clocks up for
38 * that.  The former can return an error, but the latter is expected
39 * not to.
40 *
41 * We currently are pretty rudimentary here, always selecting
42 * EXT_REF_CLK_1 for LCD0 and erroring LCD1.  This needs improvement!
43 */
44static int armada510_crtc_compute_clock(struct armada_crtc *dcrtc,
45	const struct drm_display_mode *mode, uint32_t *sclk)
46{
47	struct clk *clk = dcrtc->extclk[0];
48	int ret;
49
50	if (dcrtc->num == 1)
51		return -EINVAL;
52
53	if (IS_ERR(clk))
54		return PTR_ERR(clk);
55
56	if (dcrtc->clk != clk) {
57		ret = clk_prepare_enable(clk);
58		if (ret)
59			return ret;
60		dcrtc->clk = clk;
61	}
62
63	if (sclk) {
64		uint32_t rate, ref, div;
65
66		rate = mode->clock * 1000;
67		ref = clk_round_rate(clk, rate);
68		div = DIV_ROUND_UP(ref, rate);
69		if (div < 1)
70			div = 1;
71
72		clk_set_rate(clk, ref);
73		*sclk = div | SCLK_510_EXTCLK1;
74	}
75
76	return 0;
77}
78
79const struct armada_variant armada510_ops = {
80	.has_spu_adv_reg = true,
81	.spu_adv_reg = ADV_HWC32ENABLE | ADV_HWC32ARGB | ADV_HWC32BLEND,
82	.init = armada510_crtc_init,
83	.compute_clock = armada510_crtc_compute_clock,
84};
85