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/drm_crtc_helper.h>
13 #include "armada_crtc.h"
14 #include "armada_drm.h"
15 #include "armada_hw.h"
16 
17 static int armada510_crtc_init(struct armada_crtc *dcrtc, struct device *dev)
18 {
19 	struct clk *clk;
20 
21 	clk = devm_clk_get(dev, "ext_ref_clk1");
22 	if (IS_ERR(clk))
23 		return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER : PTR_ERR(clk);
24 
25 	dcrtc->extclk[0] = clk;
26 
27 	/* Lower the watermark so to eliminate jitter at higher bandwidths */
28 	armada_updatel(0x20, (1 << 11) | 0xff, dcrtc->base + LCD_CFG_RDREG4F);
29 
30 	/* Initialise SPU register */
31 	writel_relaxed(ADV_HWC32ENABLE | ADV_HWC32ARGB | ADV_HWC32BLEND,
32 		       dcrtc->base + LCD_SPU_ADV_REG);
33 
34 	return 0;
35 }
36 
37 /*
38  * Armada510 specific SCLK register selection.
39  * This gets called with sclk = NULL to test whether the mode is
40  * supportable, and again with sclk != NULL to set the clocks up for
41  * that.  The former can return an error, but the latter is expected
42  * not to.
43  *
44  * We currently are pretty rudimentary here, always selecting
45  * EXT_REF_CLK_1 for LCD0 and erroring LCD1.  This needs improvement!
46  */
47 static int armada510_crtc_compute_clock(struct armada_crtc *dcrtc,
48 	const struct drm_display_mode *mode, uint32_t *sclk)
49 {
50 	struct clk *clk = dcrtc->extclk[0];
51 	int ret;
52 
53 	if (dcrtc->num == 1)
54 		return -EINVAL;
55 
56 	if (IS_ERR(clk))
57 		return PTR_ERR(clk);
58 
59 	if (dcrtc->clk != clk) {
60 		ret = clk_prepare_enable(clk);
61 		if (ret)
62 			return ret;
63 		dcrtc->clk = clk;
64 	}
65 
66 	if (sclk) {
67 		uint32_t rate, ref, div;
68 
69 		rate = mode->clock * 1000;
70 		ref = clk_round_rate(clk, rate);
71 		div = DIV_ROUND_UP(ref, rate);
72 		if (div < 1)
73 			div = 1;
74 
75 		clk_set_rate(clk, ref);
76 		*sclk = div | SCLK_510_EXTCLK1;
77 	}
78 
79 	return 0;
80 }
81 
82 static void armada510_crtc_disable(struct armada_crtc *dcrtc)
83 {
84 	if (!IS_ERR(dcrtc->clk)) {
85 		clk_disable_unprepare(dcrtc->clk);
86 		dcrtc->clk = ERR_PTR(-EINVAL);
87 	}
88 }
89 
90 static void armada510_crtc_enable(struct armada_crtc *dcrtc,
91 	const struct drm_display_mode *mode)
92 {
93 	if (IS_ERR(dcrtc->clk)) {
94 		dcrtc->clk = dcrtc->extclk[0];
95 		WARN_ON(clk_prepare_enable(dcrtc->clk));
96 	}
97 }
98 
99 const struct armada_variant armada510_ops = {
100 	.has_spu_adv_reg = true,
101 	.init = armada510_crtc_init,
102 	.compute_clock = armada510_crtc_compute_clock,
103 	.disable = armada510_crtc_disable,
104 	.enable = armada510_crtc_enable,
105 };
106