1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) Guangzhou FriendlyARM Computer Tech. Co., Ltd.
4 * (http://www.friendlyarm.com)
5 */
6
7 #include <config.h>
8 #include <common.h>
9 #include <errno.h>
10 #include <asm/io.h>
11 #include <asm/arch/clk.h>
12 #include <i2c.h>
13 #include <pwm.h>
14
15 #include <irq_func.h>
16
17 #include <asm/arch/nexell.h>
18 #include <asm/arch/nx_gpio.h>
19
20 #ifndef NSEC_PER_SEC
21 #define NSEC_PER_SEC 1000000000L
22 #endif
23
24 #define SAMPLE_BPS 9600
25 #define SAMPLE_IN_US 101 /* (1000000 / BPS) */
26
27 #define REQ_INFO 0x60U
28 #define REQ_BL 0x80U
29
30 #define BUS_I2C 0x18
31 #define ONEWIRE_I2C_BUS 2
32 #define ONEWIRE_I2C_ADDR 0x2f
33
34 static int bus_type = -1;
35 static int lcd_id = -1;
36 static unsigned short lcd_fwrev;
37 static int current_brightness = -1;
38 #if CONFIG_IS_ENABLED(DM_I2C)
39 static struct udevice *i2c_dev;
40 #endif
41
42 /* debug */
43 #if (0)
44 #define DBGOUT(msg...) do { printf("onewire: " msg); } while (0)
45 #else
46 #define DBGOUT(msg...) do {} while (0)
47 #endif
48
49 /* based on web page from http://lfh1986.blogspot.com */
crc8_ow(unsigned int v,unsigned int len)50 static unsigned char crc8_ow(unsigned int v, unsigned int len)
51 {
52 unsigned char crc = 0xACU;
53
54 while (len--) {
55 if ((crc & 0x80U) != 0) {
56 crc <<= 1;
57 crc ^= 0x7U;
58 } else {
59 crc <<= 1;
60 }
61 if ((v & (1U << 31)) != 0)
62 crc ^= 0x7U;
63 v <<= 1;
64 }
65 return crc;
66 }
67
68 /* GPIO helpers */
69 #define __IO_GRP 2 /* GPIOC15 */
70 #define __IO_IDX 15
71
set_pin_as_input(void)72 static inline void set_pin_as_input(void)
73 {
74 nx_gpio_set_output_enable(__IO_GRP, __IO_IDX, 0);
75 }
76
set_pin_as_output(void)77 static inline void set_pin_as_output(void)
78 {
79 nx_gpio_set_output_enable(__IO_GRP, __IO_IDX, 1);
80 }
81
set_pin_value(int v)82 static inline void set_pin_value(int v)
83 {
84 nx_gpio_set_output_value(__IO_GRP, __IO_IDX, !!v);
85 }
86
get_pin_value(void)87 static inline int get_pin_value(void)
88 {
89 return nx_gpio_get_input_value(__IO_GRP, __IO_IDX);
90 }
91
92 /* Timer helpers */
93 #define PWM_CH 3
94 #define PWM_TCON (PHY_BASEADDR_PWM + 0x08)
95 #define PWM_TCON_START (1 << 16)
96 #define PWM_TINT_CSTAT (PHY_BASEADDR_PWM + 0x44)
97
onewire_init_timer(void)98 static int onewire_init_timer(void)
99 {
100 int period_ns = NSEC_PER_SEC / SAMPLE_BPS;
101
102 /* range: 1080~1970 */
103 period_ns -= 1525;
104
105 return pwm_config(PWM_CH, period_ns >> 1, period_ns);
106 }
107
wait_one_tick(void)108 static void wait_one_tick(void)
109 {
110 unsigned int tcon;
111
112 tcon = readl(PWM_TCON);
113 tcon |= PWM_TCON_START;
114 writel(tcon, PWM_TCON);
115
116 while (1) {
117 if (readl(PWM_TINT_CSTAT) & (1 << (5 + PWM_CH)))
118 break;
119 }
120
121 writel((1 << (5 + PWM_CH)), PWM_TINT_CSTAT);
122
123 tcon &= ~PWM_TCON_START;
124 writel(tcon, PWM_TCON);
125 }
126
127 /* Session handler */
onewire_session(unsigned char req,unsigned char res[])128 static int onewire_session(unsigned char req, unsigned char res[])
129 {
130 unsigned int Req;
131 unsigned int *Res;
132 int ints = disable_interrupts();
133 int i;
134 int ret;
135
136 Req = (req << 24) | (crc8_ow(req << 24, 8) << 16);
137 Res = (unsigned int *)res;
138
139 set_pin_value(1);
140 set_pin_as_output();
141 for (i = 0; i < 60; i++)
142 wait_one_tick();
143
144 set_pin_value(0);
145 for (i = 0; i < 2; i++)
146 wait_one_tick();
147
148 for (i = 0; i < 16; i++) {
149 int v = !!(Req & (1U << 31));
150
151 Req <<= 1;
152 set_pin_value(v);
153 wait_one_tick();
154 }
155
156 wait_one_tick();
157 set_pin_as_input();
158 wait_one_tick();
159 for (i = 0; i < 32; i++) {
160 (*Res) <<= 1;
161 (*Res) |= get_pin_value();
162 wait_one_tick();
163 }
164 set_pin_value(1);
165 set_pin_as_output();
166
167 if (ints)
168 enable_interrupts();
169
170 ret = crc8_ow(*Res, 24) == res[0];
171 DBGOUT("req = %02X, res = %02X%02X%02X%02X, ret = %d\n",
172 req, res[3], res[2], res[1], res[0], ret);
173
174 return ret;
175 }
176
onewire_i2c_do_request(unsigned char req,unsigned char * buf)177 static int onewire_i2c_do_request(unsigned char req, unsigned char *buf)
178 {
179 unsigned char tx[4];
180 int ret;
181
182 tx[0] = req;
183 tx[1] = crc8_ow(req << 24, 8);
184
185 #if CONFIG_IS_ENABLED(DM_I2C)
186 if (dm_i2c_write(i2c_dev, 0, tx, 2))
187 return -EIO;
188
189 if (!buf)
190 return 0;
191
192 if (dm_i2c_read(i2c_dev, 0, buf, 4))
193 return -EIO;
194 #else
195 if (i2c_write(ONEWIRE_I2C_ADDR, 0, 0, tx, 2))
196 return -EIO;
197
198 if (!buf) /* NO READ */
199 return 0;
200
201 if (i2c_read(ONEWIRE_I2C_ADDR, 0, 0, buf, 4))
202 return -EIO;
203 #endif
204
205 ret = crc8_ow((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8), 24);
206 DBGOUT("req = %02X, res = %02X%02X%02X%02X, ret = %02x\n",
207 req, buf[0], buf[1], buf[2], buf[3], ret);
208
209 return (ret == buf[3]) ? 0 : -EIO;
210 }
211
onewire_i2c_init(void)212 static void onewire_i2c_init(void)
213 {
214 unsigned char buf[4];
215 int ret;
216
217 #if CONFIG_IS_ENABLED(DM_I2C)
218 ret = i2c_get_chip_for_busnum(ONEWIRE_I2C_BUS,
219 ONEWIRE_I2C_ADDR, 0, &i2c_dev);
220 #else
221 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
222 i2c_set_bus_num(ONEWIRE_I2C_BUS);
223
224 ret = i2c_probe(ONEWIRE_I2C_ADDR);
225 #endif
226 if (ret)
227 return;
228
229 ret = onewire_i2c_do_request(REQ_INFO, buf);
230 if (!ret) {
231 lcd_id = buf[0];
232 lcd_fwrev = buf[1] * 0x100 + buf[2];
233 bus_type = BUS_I2C;
234 }
235 }
236
onewire_init(void)237 void onewire_init(void)
238 {
239 /* GPIO, Pull-off */
240 nx_gpio_set_pad_function(__IO_GRP, __IO_IDX, 1);
241 nx_gpio_set_pull_mode(__IO_GRP, __IO_IDX, 2);
242
243 onewire_init_timer();
244 onewire_i2c_init();
245 }
246
onewire_get_info(unsigned char * lcd,unsigned short * fw_ver)247 int onewire_get_info(unsigned char *lcd, unsigned short *fw_ver)
248 {
249 unsigned char res[4];
250 int i;
251
252 if (bus_type == BUS_I2C && lcd_id > 0) {
253 *lcd = lcd_id;
254 *fw_ver = lcd_fwrev;
255 return 0;
256 }
257
258 for (i = 0; i < 3; i++) {
259 if (onewire_session(REQ_INFO, res)) {
260 *lcd = res[3];
261 *fw_ver = res[2] * 0x100 + res[1];
262 lcd_id = *lcd;
263 DBGOUT("lcd = %d, fw_ver = %x\n", *lcd, *fw_ver);
264 return 0;
265 }
266 }
267
268 /* LCD unknown or not connected */
269 *lcd = 0;
270 *fw_ver = -1;
271
272 return -1;
273 }
274
onewire_get_lcd_id(void)275 int onewire_get_lcd_id(void)
276 {
277 return lcd_id;
278 }
279
onewire_set_backlight(int brightness)280 int onewire_set_backlight(int brightness)
281 {
282 unsigned char res[4];
283 int i;
284
285 if (brightness == current_brightness)
286 return 0;
287
288 if (brightness > 127)
289 brightness = 127;
290 else if (brightness < 0)
291 brightness = 0;
292
293 if (bus_type == BUS_I2C) {
294 onewire_i2c_do_request((REQ_BL | brightness), NULL);
295 current_brightness = brightness;
296 return 0;
297 }
298
299 for (i = 0; i < 3; i++) {
300 if (onewire_session((REQ_BL | brightness), res)) {
301 current_brightness = brightness;
302 return 0;
303 }
304 }
305
306 return -1;
307 }
308