1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2020 Unisoc Inc.
4  */
5 
6 #include <asm/div64.h>
7 #include <linux/delay.h>
8 #include <linux/init.h>
9 #include <linux/kernel.h>
10 #include <linux/regmap.h>
11 #include <linux/string.h>
12 
13 #include "sprd_dsi.h"
14 
15 #define L						0
16 #define H						1
17 #define CLK						0
18 #define DATA					1
19 #define INFINITY				0xffffffff
20 #define MIN_OUTPUT_FREQ			(100)
21 
22 #define AVERAGE(a, b) (min(a, b) + abs((b) - (a)) / 2)
23 
24 /* sharkle */
25 #define VCO_BAND_LOW	750
26 #define VCO_BAND_MID	1100
27 #define VCO_BAND_HIGH	1500
28 #define PHY_REF_CLK	26000
29 
30 static int dphy_calc_pll_param(struct dphy_pll *pll)
31 {
32 	const u32 khz = 1000;
33 	const u32 mhz = 1000000;
34 	const unsigned long long factor = 100;
35 	unsigned long long tmp;
36 	int i;
37 
38 	pll->potential_fvco = pll->freq / khz;
39 	pll->ref_clk = PHY_REF_CLK / khz;
40 
41 	for (i = 0; i < 4; ++i) {
42 		if (pll->potential_fvco >= VCO_BAND_LOW &&
43 		    pll->potential_fvco <= VCO_BAND_HIGH) {
44 			pll->fvco = pll->potential_fvco;
45 			pll->out_sel = BIT(i);
46 			break;
47 		}
48 		pll->potential_fvco <<= 1;
49 	}
50 	if (pll->fvco == 0)
51 		return -EINVAL;
52 
53 	if (pll->fvco >= VCO_BAND_LOW && pll->fvco <= VCO_BAND_MID) {
54 		/* vco band control */
55 		pll->vco_band = 0x0;
56 		/* low pass filter control */
57 		pll->lpf_sel = 1;
58 	} else if (pll->fvco > VCO_BAND_MID && pll->fvco <= VCO_BAND_HIGH) {
59 		pll->vco_band = 0x1;
60 		pll->lpf_sel = 0;
61 	} else {
62 		return -EINVAL;
63 	}
64 
65 	pll->nint = pll->fvco / pll->ref_clk;
66 	tmp = pll->fvco * factor * mhz;
67 	do_div(tmp, pll->ref_clk);
68 	tmp = tmp - pll->nint * factor * mhz;
69 	tmp *= BIT(20);
70 	do_div(tmp, 100000000);
71 	pll->kint = (u32)tmp;
72 	pll->refin = 3; /* pre-divider bypass */
73 	pll->sdm_en = true; /* use fraction N PLL */
74 	pll->fdk_s = 0x1; /* fraction */
75 	pll->cp_s = 0x0;
76 	pll->det_delay = 0x1;
77 
78 	return 0;
79 }
80 
81 static void dphy_set_pll_reg(struct dphy_pll *pll, struct regmap *regmap)
82 {
83 	u8 reg_val[9] = {0};
84 	int i;
85 
86 	u8 reg_addr[] = {
87 		0x03, 0x04, 0x06, 0x08, 0x09,
88 		0x0a, 0x0b, 0x0e, 0x0f
89 	};
90 
91 	reg_val[0] = 1 | (1 << 1) |  (pll->lpf_sel << 2);
92 	reg_val[1] = pll->div | (1 << 3) | (pll->cp_s << 5) | (pll->fdk_s << 7);
93 	reg_val[2] = pll->nint;
94 	reg_val[3] = pll->vco_band | (pll->sdm_en << 1) | (pll->refin << 2);
95 	reg_val[4] = pll->kint >> 12;
96 	reg_val[5] = pll->kint >> 4;
97 	reg_val[6] = pll->out_sel | ((pll->kint << 4) & 0xf);
98 	reg_val[7] = 1 << 4;
99 	reg_val[8] = pll->det_delay;
100 
101 	for (i = 0; i < sizeof(reg_addr); ++i) {
102 		regmap_write(regmap, reg_addr[i], reg_val[i]);
103 		DRM_DEBUG("%02x: %02x\n", reg_addr[i], reg_val[i]);
104 	}
105 }
106 
107 int dphy_pll_config(struct dsi_context *ctx)
108 {
109 	struct sprd_dsi *dsi = container_of(ctx, struct sprd_dsi, ctx);
110 	struct regmap *regmap = ctx->regmap;
111 	struct dphy_pll *pll = &ctx->pll;
112 	int ret;
113 
114 	pll->freq = dsi->slave->hs_rate;
115 
116 	/* FREQ = 26M * (NINT + KINT / 2^20) / out_sel */
117 	ret = dphy_calc_pll_param(pll);
118 	if (ret) {
119 		drm_err(dsi->drm, "failed to calculate dphy pll parameters\n");
120 		return ret;
121 	}
122 	dphy_set_pll_reg(pll, regmap);
123 
124 	return 0;
125 }
126 
127 static void dphy_set_timing_reg(struct regmap *regmap, int type, u8 val[])
128 {
129 	switch (type) {
130 	case REQUEST_TIME:
131 		regmap_write(regmap, 0x31, val[CLK]);
132 		regmap_write(regmap, 0x41, val[DATA]);
133 		regmap_write(regmap, 0x51, val[DATA]);
134 		regmap_write(regmap, 0x61, val[DATA]);
135 		regmap_write(regmap, 0x71, val[DATA]);
136 
137 		regmap_write(regmap, 0x90, val[CLK]);
138 		regmap_write(regmap, 0xa0, val[DATA]);
139 		regmap_write(regmap, 0xb0, val[DATA]);
140 		regmap_write(regmap, 0xc0, val[DATA]);
141 		regmap_write(regmap, 0xd0, val[DATA]);
142 		break;
143 	case PREPARE_TIME:
144 		regmap_write(regmap, 0x32, val[CLK]);
145 		regmap_write(regmap, 0x42, val[DATA]);
146 		regmap_write(regmap, 0x52, val[DATA]);
147 		regmap_write(regmap, 0x62, val[DATA]);
148 		regmap_write(regmap, 0x72, val[DATA]);
149 
150 		regmap_write(regmap, 0x91, val[CLK]);
151 		regmap_write(regmap, 0xa1, val[DATA]);
152 		regmap_write(regmap, 0xb1, val[DATA]);
153 		regmap_write(regmap, 0xc1, val[DATA]);
154 		regmap_write(regmap, 0xd1, val[DATA]);
155 		break;
156 	case ZERO_TIME:
157 		regmap_write(regmap, 0x33, val[CLK]);
158 		regmap_write(regmap, 0x43, val[DATA]);
159 		regmap_write(regmap, 0x53, val[DATA]);
160 		regmap_write(regmap, 0x63, val[DATA]);
161 		regmap_write(regmap, 0x73, val[DATA]);
162 
163 		regmap_write(regmap, 0x92, val[CLK]);
164 		regmap_write(regmap, 0xa2, val[DATA]);
165 		regmap_write(regmap, 0xb2, val[DATA]);
166 		regmap_write(regmap, 0xc2, val[DATA]);
167 		regmap_write(regmap, 0xd2, val[DATA]);
168 		break;
169 	case TRAIL_TIME:
170 		regmap_write(regmap, 0x34, val[CLK]);
171 		regmap_write(regmap, 0x44, val[DATA]);
172 		regmap_write(regmap, 0x54, val[DATA]);
173 		regmap_write(regmap, 0x64, val[DATA]);
174 		regmap_write(regmap, 0x74, val[DATA]);
175 
176 		regmap_write(regmap, 0x93, val[CLK]);
177 		regmap_write(regmap, 0xa3, val[DATA]);
178 		regmap_write(regmap, 0xb3, val[DATA]);
179 		regmap_write(regmap, 0xc3, val[DATA]);
180 		regmap_write(regmap, 0xd3, val[DATA]);
181 		break;
182 	case EXIT_TIME:
183 		regmap_write(regmap, 0x36, val[CLK]);
184 		regmap_write(regmap, 0x46, val[DATA]);
185 		regmap_write(regmap, 0x56, val[DATA]);
186 		regmap_write(regmap, 0x66, val[DATA]);
187 		regmap_write(regmap, 0x76, val[DATA]);
188 
189 		regmap_write(regmap, 0x95, val[CLK]);
190 		regmap_write(regmap, 0xA5, val[DATA]);
191 		regmap_write(regmap, 0xB5, val[DATA]);
192 		regmap_write(regmap, 0xc5, val[DATA]);
193 		regmap_write(regmap, 0xd5, val[DATA]);
194 		break;
195 	case CLKPOST_TIME:
196 		regmap_write(regmap, 0x35, val[CLK]);
197 		regmap_write(regmap, 0x94, val[CLK]);
198 		break;
199 
200 	/* the following just use default value */
201 	case SETTLE_TIME:
202 		fallthrough;
203 	case TA_GET:
204 		fallthrough;
205 	case TA_GO:
206 		fallthrough;
207 	case TA_SURE:
208 		fallthrough;
209 	default:
210 		break;
211 	}
212 }
213 
214 void dphy_timing_config(struct dsi_context *ctx)
215 {
216 	struct regmap *regmap = ctx->regmap;
217 	struct dphy_pll *pll = &ctx->pll;
218 	const u32 factor = 2;
219 	const u32 scale = 100;
220 	u32 t_ui, t_byteck, t_half_byteck;
221 	u32 range[2], constant;
222 	u8 val[2];
223 	u32 tmp = 0;
224 
225 	/* t_ui: 1 ui, byteck: 8 ui, half byteck: 4 ui */
226 	t_ui = 1000 * scale / (pll->freq / 1000);
227 	t_byteck = t_ui << 3;
228 	t_half_byteck = t_ui << 2;
229 	constant = t_ui << 1;
230 
231 	/* REQUEST_TIME: HS T-LPX: LP-01
232 	 * For T-LPX, mipi spec defined min value is 50ns,
233 	 * but maybe it shouldn't be too small, because BTA,
234 	 * LP-10, LP-00, LP-01, all of this is related to T-LPX.
235 	 */
236 	range[L] = 50 * scale;
237 	range[H] = INFINITY;
238 	val[CLK] = DIV_ROUND_UP(range[L] * (factor << 1), t_byteck) - 2;
239 	val[DATA] = val[CLK];
240 	dphy_set_timing_reg(regmap, REQUEST_TIME, val);
241 
242 	/* PREPARE_TIME: HS sequence: LP-00 */
243 	range[L] = 38 * scale;
244 	range[H] = 95 * scale;
245 	tmp = AVERAGE(range[L], range[H]);
246 	val[CLK] = DIV_ROUND_UP(AVERAGE(range[L], range[H]), t_half_byteck) - 1;
247 	range[L] = 40 * scale + 4 * t_ui;
248 	range[H] = 85 * scale + 6 * t_ui;
249 	tmp |= AVERAGE(range[L], range[H]) << 16;
250 	val[DATA] = DIV_ROUND_UP(AVERAGE(range[L], range[H]), t_half_byteck) - 1;
251 	dphy_set_timing_reg(regmap, PREPARE_TIME, val);
252 
253 	/* ZERO_TIME: HS-ZERO */
254 	range[L] = 300 * scale;
255 	range[H] = INFINITY;
256 	val[CLK] = DIV_ROUND_UP(range[L] * factor + (tmp & 0xffff)
257 			- 525 * t_byteck / 100, t_byteck) - 2;
258 	range[L] = 145 * scale + 10 * t_ui;
259 	val[DATA] = DIV_ROUND_UP(range[L] * factor
260 			+ ((tmp >> 16) & 0xffff) - 525 * t_byteck / 100,
261 			t_byteck) - 2;
262 	dphy_set_timing_reg(regmap, ZERO_TIME, val);
263 
264 	/* TRAIL_TIME: HS-TRAIL */
265 	range[L] = 60 * scale;
266 	range[H] = INFINITY;
267 	val[CLK] = DIV_ROUND_UP(range[L] * factor - constant, t_half_byteck);
268 	range[L] = max(8 * t_ui, 60 * scale + 4 * t_ui);
269 	val[DATA] = DIV_ROUND_UP(range[L] * 3 / 2 - constant, t_half_byteck) - 2;
270 	dphy_set_timing_reg(regmap, TRAIL_TIME, val);
271 
272 	/* EXIT_TIME: */
273 	range[L] = 100 * scale;
274 	range[H] = INFINITY;
275 	val[CLK] = DIV_ROUND_UP(range[L] * factor, t_byteck) - 2;
276 	val[DATA] = val[CLK];
277 	dphy_set_timing_reg(regmap, EXIT_TIME, val);
278 
279 	/* CLKPOST_TIME: */
280 	range[L] = 60 * scale + 52 * t_ui;
281 	range[H] = INFINITY;
282 	val[CLK] = DIV_ROUND_UP(range[L] * factor, t_byteck) - 2;
283 	val[DATA] = val[CLK];
284 	dphy_set_timing_reg(regmap, CLKPOST_TIME, val);
285 
286 	/* SETTLE_TIME:
287 	 * This time is used for receiver. So for transmitter,
288 	 * it can be ignored.
289 	 */
290 
291 	/* TA_GO:
292 	 * transmitter drives bridge state(LP-00) before releasing control,
293 	 * reg 0x1f default value: 0x04, which is good.
294 	 */
295 
296 	/* TA_SURE:
297 	 * After LP-10 state and before bridge state(LP-00),
298 	 * reg 0x20 default value: 0x01, which is good.
299 	 */
300 
301 	/* TA_GET:
302 	 * receiver drives Bridge state(LP-00) before releasing control
303 	 * reg 0x21 default value: 0x03, which is good.
304 	 */
305 }
306