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