1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2012 Russell King
4  *
5  * Armada 510 (aka Dove) variant support
6  */
7 #include <linux/clk.h>
8 #include <linux/io.h>
9 #include <linux/of.h>
10 #include <drm/drm_probe_helper.h>
11 #include "armada_crtc.h"
12 #include "armada_drm.h"
13 #include "armada_hw.h"
14 
15 struct armada510_variant_data {
16 	struct clk *clks[4];
17 	struct clk *sel_clk;
18 };
19 
20 static int armada510_crtc_init(struct armada_crtc *dcrtc, struct device *dev)
21 {
22 	struct armada510_variant_data *v;
23 	struct clk *clk;
24 	int idx;
25 
26 	v = devm_kzalloc(dev, sizeof(*v), GFP_KERNEL);
27 	if (!v)
28 		return -ENOMEM;
29 
30 	dcrtc->variant_data = v;
31 
32 	if (dev->of_node) {
33 		struct property *prop;
34 		const char *s;
35 
36 		of_property_for_each_string(dev->of_node, "clock-names", prop,
37 					    s) {
38 			if (!strcmp(s, "ext_ref_clk0"))
39 				idx = 0;
40 			else if (!strcmp(s, "ext_ref_clk1"))
41 				idx = 1;
42 			else if (!strcmp(s, "plldivider"))
43 				idx = 2;
44 			else if (!strcmp(s, "axibus"))
45 				idx = 3;
46 			else
47 				continue;
48 
49 			clk = devm_clk_get(dev, s);
50 			if (IS_ERR(clk))
51 				return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER :
52 					PTR_ERR(clk);
53 			v->clks[idx] = clk;
54 		}
55 	} else {
56 		clk = devm_clk_get(dev, "ext_ref_clk1");
57 		if (IS_ERR(clk))
58 			return PTR_ERR(clk) == -ENOENT ? -EPROBE_DEFER :
59 				PTR_ERR(clk);
60 
61 		v->clks[1] = clk;
62 	}
63 
64 	/*
65 	 * Lower the watermark so to eliminate jitter at higher bandwidths.
66 	 * Disable SRAM read wait state to avoid system hang with external
67 	 * clock.
68 	 */
69 	armada_updatel(CFG_DMA_WM(0x20), CFG_SRAM_WAIT | CFG_DMA_WM_MASK,
70 		       dcrtc->base + LCD_CFG_RDREG4F);
71 
72 	/* Initialise SPU register */
73 	writel_relaxed(ADV_HWC32ENABLE | ADV_HWC32ARGB | ADV_HWC32BLEND,
74 		       dcrtc->base + LCD_SPU_ADV_REG);
75 
76 	return 0;
77 }
78 
79 static const u32 armada510_clk_sels[] = {
80 	SCLK_510_EXTCLK0,
81 	SCLK_510_EXTCLK1,
82 	SCLK_510_PLL,
83 	SCLK_510_AXI,
84 };
85 
86 static const struct armada_clocking_params armada510_clocking = {
87 	/* HDMI requires -0.6%..+0.5% */
88 	.permillage_min = 994,
89 	.permillage_max = 1005,
90 	.settable = BIT(0) | BIT(1),
91 	.div_max = SCLK_510_INT_DIV_MASK,
92 };
93 
94 /*
95  * Armada510 specific SCLK register selection.
96  * This gets called with sclk = NULL to test whether the mode is
97  * supportable, and again with sclk != NULL to set the clocks up for
98  * that.  The former can return an error, but the latter is expected
99  * not to.
100  */
101 static int armada510_crtc_compute_clock(struct armada_crtc *dcrtc,
102 	const struct drm_display_mode *mode, uint32_t *sclk)
103 {
104 	struct armada510_variant_data *v = dcrtc->variant_data;
105 	unsigned long desired_khz = mode->crtc_clock;
106 	struct armada_clk_result res;
107 	int ret, idx;
108 
109 	idx = armada_crtc_select_clock(dcrtc, &res, &armada510_clocking,
110 				       v->clks, ARRAY_SIZE(v->clks),
111 				       desired_khz);
112 	if (idx < 0)
113 		return idx;
114 
115 	ret = clk_prepare_enable(res.clk);
116 	if (ret)
117 		return ret;
118 
119 	if (sclk) {
120 		clk_set_rate(res.clk, res.desired_clk_hz);
121 
122 		*sclk = res.div | armada510_clk_sels[idx];
123 
124 		/* We are now using this clock */
125 		v->sel_clk = res.clk;
126 		swap(dcrtc->clk, res.clk);
127 	}
128 
129 	clk_disable_unprepare(res.clk);
130 
131 	return 0;
132 }
133 
134 static void armada510_crtc_disable(struct armada_crtc *dcrtc)
135 {
136 	if (dcrtc->clk) {
137 		clk_disable_unprepare(dcrtc->clk);
138 		dcrtc->clk = NULL;
139 	}
140 }
141 
142 static void armada510_crtc_enable(struct armada_crtc *dcrtc,
143 	const struct drm_display_mode *mode)
144 {
145 	struct armada510_variant_data *v = dcrtc->variant_data;
146 
147 	if (!dcrtc->clk && v->sel_clk) {
148 		if (!WARN_ON(clk_prepare_enable(v->sel_clk)))
149 			dcrtc->clk = v->sel_clk;
150 	}
151 }
152 
153 const struct armada_variant armada510_ops = {
154 	.has_spu_adv_reg = true,
155 	.init = armada510_crtc_init,
156 	.compute_clock = armada510_crtc_compute_clock,
157 	.disable = armada510_crtc_disable,
158 	.enable = armada510_crtc_enable,
159 };
160