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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 <asm/arch/pwm.h>
#include <i2c.h>
#include <linux/time.h>
#include <irq_func.h>
#include <asm/arch/nexell.h>
#include <asm/arch/nx_gpio.h>
#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;
#if CONFIG_IS_ENABLED(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 s5p_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);
#if CONFIG_IS_ENABLED(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;
#if CONFIG_IS_ENABLED(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;
}