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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (C) Guangzhou FriendlyARM Computer Tech. Co., Ltd.
- * (http://www.friendlyarm.com)
- */
- #include <config.h>
- #include <common.h>
- #include <errno.h>
- #include <asm/io.h>
- #include <asm/arch/clk.h>
- #include <i2c.h>
- #include <pwm.h>
- #include <irq_func.h>
- #include <asm/arch/nexell.h>
- #include <asm/arch/nx_gpio.h>
- #ifndef NSEC_PER_SEC
- #define NSEC_PER_SEC 1000000000L
- #endif
- #define SAMPLE_BPS 9600
- #define SAMPLE_IN_US 101 /* (1000000 / BPS) */
- #define REQ_INFO 0x60U
- #define REQ_BL 0x80U
- #define BUS_I2C 0x18
- #define ONEWIRE_I2C_BUS 2
- #define ONEWIRE_I2C_ADDR 0x2f
- static int bus_type = -1;
- static int lcd_id = -1;
- static unsigned short lcd_fwrev;
- static int current_brightness = -1;
- #ifdef CONFIG_DM_I2C
- static struct udevice *i2c_dev;
- #endif
- /* debug */
- #if (0)
- #define DBGOUT(msg...) do { printf("onewire: " msg); } while (0)
- #else
- #define DBGOUT(msg...) do {} while (0)
- #endif
- /* based on web page from http://lfh1986.blogspot.com */
- static unsigned char crc8_ow(unsigned int v, unsigned int len)
- {
- unsigned char crc = 0xACU;
- while (len--) {
- if ((crc & 0x80U) != 0) {
- crc <<= 1;
- crc ^= 0x7U;
- } else {
- crc <<= 1;
- }
- if ((v & (1U << 31)) != 0)
- crc ^= 0x7U;
- v <<= 1;
- }
- return crc;
- }
- /* GPIO helpers */
- #define __IO_GRP 2 /* GPIOC15 */
- #define __IO_IDX 15
- static inline void set_pin_as_input(void)
- {
- nx_gpio_set_output_enable(__IO_GRP, __IO_IDX, 0);
- }
- static inline void set_pin_as_output(void)
- {
- nx_gpio_set_output_enable(__IO_GRP, __IO_IDX, 1);
- }
- static inline void set_pin_value(int v)
- {
- nx_gpio_set_output_value(__IO_GRP, __IO_IDX, !!v);
- }
- static inline int get_pin_value(void)
- {
- return nx_gpio_get_input_value(__IO_GRP, __IO_IDX);
- }
- /* Timer helpers */
- #define PWM_CH 3
- #define PWM_TCON (PHY_BASEADDR_PWM + 0x08)
- #define PWM_TCON_START (1 << 16)
- #define PWM_TINT_CSTAT (PHY_BASEADDR_PWM + 0x44)
- static int onewire_init_timer(void)
- {
- int period_ns = NSEC_PER_SEC / SAMPLE_BPS;
- /* range: 1080~1970 */
- period_ns -= 1525;
- return pwm_config(PWM_CH, period_ns >> 1, period_ns);
- }
- static void wait_one_tick(void)
- {
- unsigned int tcon;
- tcon = readl(PWM_TCON);
- tcon |= PWM_TCON_START;
- writel(tcon, PWM_TCON);
- while (1) {
- if (readl(PWM_TINT_CSTAT) & (1 << (5 + PWM_CH)))
- break;
- }
- writel((1 << (5 + PWM_CH)), PWM_TINT_CSTAT);
- tcon &= ~PWM_TCON_START;
- writel(tcon, PWM_TCON);
- }
- /* Session handler */
- static int onewire_session(unsigned char req, unsigned char res[])
- {
- unsigned int Req;
- unsigned int *Res;
- int ints = disable_interrupts();
- int i;
- int ret;
- Req = (req << 24) | (crc8_ow(req << 24, 8) << 16);
- Res = (unsigned int *)res;
- set_pin_value(1);
- set_pin_as_output();
- for (i = 0; i < 60; i++)
- wait_one_tick();
- set_pin_value(0);
- for (i = 0; i < 2; i++)
- wait_one_tick();
- for (i = 0; i < 16; i++) {
- int v = !!(Req & (1U << 31));
- Req <<= 1;
- set_pin_value(v);
- wait_one_tick();
- }
- wait_one_tick();
- set_pin_as_input();
- wait_one_tick();
- for (i = 0; i < 32; i++) {
- (*Res) <<= 1;
- (*Res) |= get_pin_value();
- wait_one_tick();
- }
- set_pin_value(1);
- set_pin_as_output();
- if (ints)
- enable_interrupts();
- ret = crc8_ow(*Res, 24) == res[0];
- DBGOUT("req = %02X, res = %02X%02X%02X%02X, ret = %d\n",
- req, res[3], res[2], res[1], res[0], ret);
- return ret;
- }
- static int onewire_i2c_do_request(unsigned char req, unsigned char *buf)
- {
- unsigned char tx[4];
- int ret;
- tx[0] = req;
- tx[1] = crc8_ow(req << 24, 8);
- #ifdef CONFIG_DM_I2C
- if (dm_i2c_write(i2c_dev, 0, tx, 2))
- return -EIO;
- if (!buf)
- return 0;
- if (dm_i2c_read(i2c_dev, 0, buf, 4))
- return -EIO;
- #else
- if (i2c_write(ONEWIRE_I2C_ADDR, 0, 0, tx, 2))
- return -EIO;
- if (!buf) /* NO READ */
- return 0;
- if (i2c_read(ONEWIRE_I2C_ADDR, 0, 0, buf, 4))
- return -EIO;
- #endif
- ret = crc8_ow((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8), 24);
- DBGOUT("req = %02X, res = %02X%02X%02X%02X, ret = %02x\n",
- req, buf[0], buf[1], buf[2], buf[3], ret);
- return (ret == buf[3]) ? 0 : -EIO;
- }
- static void onewire_i2c_init(void)
- {
- unsigned char buf[4];
- int ret;
- #ifdef CONFIG_DM_I2C
- ret = i2c_get_chip_for_busnum(ONEWIRE_I2C_BUS,
- ONEWIRE_I2C_ADDR, 0, &i2c_dev);
- #else
- i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
- i2c_set_bus_num(ONEWIRE_I2C_BUS);
- ret = i2c_probe(ONEWIRE_I2C_ADDR);
- #endif
- if (ret)
- return;
- ret = onewire_i2c_do_request(REQ_INFO, buf);
- if (!ret) {
- lcd_id = buf[0];
- lcd_fwrev = buf[1] * 0x100 + buf[2];
- bus_type = BUS_I2C;
- }
- }
- void onewire_init(void)
- {
- /* GPIO, Pull-off */
- nx_gpio_set_pad_function(__IO_GRP, __IO_IDX, 1);
- nx_gpio_set_pull_mode(__IO_GRP, __IO_IDX, 2);
- onewire_init_timer();
- onewire_i2c_init();
- }
- int onewire_get_info(unsigned char *lcd, unsigned short *fw_ver)
- {
- unsigned char res[4];
- int i;
- if (bus_type == BUS_I2C && lcd_id > 0) {
- *lcd = lcd_id;
- *fw_ver = lcd_fwrev;
- return 0;
- }
- for (i = 0; i < 3; i++) {
- if (onewire_session(REQ_INFO, res)) {
- *lcd = res[3];
- *fw_ver = res[2] * 0x100 + res[1];
- lcd_id = *lcd;
- DBGOUT("lcd = %d, fw_ver = %x\n", *lcd, *fw_ver);
- return 0;
- }
- }
- /* LCD unknown or not connected */
- *lcd = 0;
- *fw_ver = -1;
- return -1;
- }
- int onewire_get_lcd_id(void)
- {
- return lcd_id;
- }
- int onewire_set_backlight(int brightness)
- {
- unsigned char res[4];
- int i;
- if (brightness == current_brightness)
- return 0;
- if (brightness > 127)
- brightness = 127;
- else if (brightness < 0)
- brightness = 0;
- if (bus_type == BUS_I2C) {
- onewire_i2c_do_request((REQ_BL | brightness), NULL);
- current_brightness = brightness;
- return 0;
- }
- for (i = 0; i < 3; i++) {
- if (onewire_session((REQ_BL | brightness), res)) {
- current_brightness = brightness;
- return 0;
- }
- }
- return -1;
- }
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