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 
18 static 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  */
44 static 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 
79 const 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