tiny4412 设备树之LCD背光驱动（五）
程序员文章站
2022-07-14 09:38:38
...
开发板：tiny4412(1611)
内核：linux4.4
编译器： arm-none-linux-gnueabi-gcc （gcc version 4.8.3 20140320）
4412芯片gpx1 2接到双向电平转换器上：
LCD上有一个STM8单片机控制背光和传输触屏数据，通过一线协议。（触屏数据也可通过i2c直接读取）
关于一线背光驱动：
http://www.360doc.com/content/15/1031/21/6828497_509742486.shtml
devicetree
aaa@qq.com139D0000{
compatible = "tiny4412,backlight_demo";
reg = <0x139D0000 0x48>;
tiny4412,backlight = <&gpx1 2 GPIO_ACTIVE_HIGH>;
pinctrl-names = "backlight_out","backlight_in";
pinctrl-0 = <&backlight_out>;
pinctrl-1 = <&backlight_in>;
interrupts = <0 40 0>;
clocks = <&clock CLK_PWM>;
clock-names = "timers";
};
&pinctrl_1 {
backlight_out: backlight_out{
samsung,pins = "gpx1-2";
samsung,pin-function = <1>;
samsung,pin-pud = <0>;
samsung,pin-drv = <0>;
};
backlight_in: backlight_in{
samsung,pins = "gpx1-2";
samsung,pin-function = <0>;
samsung,pin-pud = <0>;
samsung,pin-drv = <0>;
};
};
驱动
//移植linux-3.5/drivers/input/touchscreen/tiny4412_1wire_host.c
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/sched.h>
#define dev_num 1
#define timer_debug printk("TCFG0: %08x\n",timer->TCFG0); \
printk("TCFG1: %08x\n",timer->TCFG1); \
printk("TCON: %08x\n",timer->TCON); \
printk("TCNTB3: %08x\n",timer->TCNTB3); \
printk("TCMPB3: %08x\n",timer->TCMPB3); \
printk("TCNTO3: %08x\n",timer->TCNTO3); \
printk("TINT_CSTAT: %08x\n",timer->TINT_CSTAT)
struct device *dev;
static struct pinctrl *pinctrl;
static struct pinctrl_state *pinctrl_in;
static struct pinctrl_state *pinctrl_out;
static struct cdev gpj1_3_cdev;
static struct class *gpj_class;
static struct device *class_dev;
static int major;
static dev_t devid;
static int onewrite_pin;
static char devname[]="one_write";
//from tiny4412-1write-host.c
static DECLARE_WAIT_QUEUE_HEAD(bl_waitq);
static int bl_ready;
static unsigned char backlight_req = 0;
static unsigned char backlight_init_success;
enum {
IDLE,
START,
REQUEST,
WAITING,
RESPONSE,
STOPING,
} one_wire_status = IDLE;
//static int err_i = 0;
static volatile unsigned int io_bit_count;
static volatile unsigned int io_data;
static volatile unsigned char one_wire_request;
struct TIMER_BASEADDR{
unsigned int TCFG0;
unsigned int TCFG1;
unsigned int TCON;
unsigned int TCNTB0;
unsigned int TCMPB0;
unsigned int TCNTO0;
unsigned int TCNTB1;
unsigned int TCMPB1;
unsigned int TCNTO1;
unsigned int TCNTB2;
unsigned int TCMPB2;
unsigned int TCNTO2;
unsigned int TCNTB3;
unsigned int TCMPB3;
unsigned int TCNTO3;
unsigned int TCNTB4;
unsigned int TCNTO4;
unsigned int TINT_CSTAT;
};
volatile struct TIMER_BASEADDR *timer;
static inline void set_pin_up(void)
{
/* TODO: */
#if 0
unsigned long tmp;
tmp = readl(S3C64XX_GPFPUD);
tmp &= ~(3U <<30);
tmp |= (2U << 30);
writel(tmp, S3C64XX_GPFPUD);
#endif
}
static inline void set_pin_as_input(void)
{
pinctrl_select_state(pinctrl,pinctrl_in);
}
static inline void set_pin_as_output(void)
{
pinctrl_select_state(pinctrl,pinctrl_out);
}
static inline void set_pin_value(int v)
{
if (v) {
gpio_set_value(onewrite_pin, 1);
} else {
gpio_set_value(onewrite_pin, 0);
}
}
static inline int get_pin_value(void)
{
return gpio_get_value(onewrite_pin);
}
// CRC
//
static const unsigned char crc8_tab[] = {
0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3,
};
#define crc8_init(crc) ((crc) = 0XACU)
#define crc8(crc, v) ( (crc) = crc8_tab[(crc) ^(v)])
// once a session complete
static unsigned total_received, total_error;
static unsigned last_req, last_res;
static inline void notify_bl_data(unsigned char a, unsigned char b, unsigned char c)
{
bl_ready = 1;
backlight_init_success = 1;
wake_up_interruptible(&bl_waitq);
}
static void one_wire_session_complete(unsigned char req, unsigned int res)
{
unsigned char crc;
const unsigned char *p = (const unsigned char*)&res;
total_received ++;
last_res = res;
crc8_init(crc);
crc8(crc, p[3]);
crc8(crc, p[2]);
crc8(crc, p[1]);
if (crc != p[0]) {
// CRC dismatch
if (total_received > 100) {
total_error++;
}
return;
}
notify_bl_data(p[3], p[2], p[1]);
}
#define S3C2410_TCON_T3START (1<<16)
// one-wire protocol core
static unsigned long TCNT_FOR_SAMPLE_BIT;
static unsigned long TCNT_FOR_FAST_LOOP;
static unsigned long TCNT_FOR_SLOW_LOOP;
#define SAMPLE_BPS 9600
#define SLOW_LOOP_FEQ 25
#define FAST_LOOP_FEQ 60
#define S3C2410_TCFG1_MUX3_MASK (15<<12)
static int init_timer_for_1wire(struct clk *clk)
{
//unsigned long tcfg1;
unsigned long tcfg0;
unsigned prescale1_value;
unsigned long pclk;
//struct clk *clk;
// get pclk
clk = clk_get(dev, "timers");
if (IS_ERR(clk)) {
printk("ERROR to get PCLK\n");
return -EIO;
}
clk_enable(clk);
pclk = clk_get_rate(clk);
printk("PWM clock = %ld\n", pclk);
// get prescaler
tcfg0 = timer->TCFG0;
// we use system prescaler value because timer 4 uses same one
prescale1_value = (tcfg0 >> 8) & 0xFF;
// calc the TCNT_FOR_SAMPLE_BIT, that is one of the goal
TCNT_FOR_SAMPLE_BIT = pclk / (prescale1_value + 1) / SAMPLE_BPS - 1;
TCNT_FOR_FAST_LOOP = pclk / (prescale1_value + 1) / FAST_LOOP_FEQ - 1;
TCNT_FOR_SLOW_LOOP = pclk / (prescale1_value + 1) / SLOW_LOOP_FEQ - 1;
// select timer 3, the 2rd goal
#if 0
tcfg1 = timer->TCFG1;
tcfg1 &= ~S3C2410_TCFG1_MUX3_MASK;
timer->TCFG1=tcfg1;
#endif
printk("TCNT_FOR_SAMPLE_BIT = %ld, TCFG1 = %08x\n",
TCNT_FOR_SAMPLE_BIT,timer->TCFG1);
return 0;
}
static inline void stop_timer_for_1wire(void)
{
unsigned long tcon;
tcon = timer->TCON;
tcon &= ~S3C2410_TCON_T3START;
timer->TCON=tcon;
}
static irqreturn_t timer_for_1wire_interrupt(int irq, void *dev_id)
{
unsigned int tint;
tint = timer->TINT_CSTAT;
tint |= 0x100;
timer->TINT_CSTAT=tint;
io_bit_count--;
switch(one_wire_status) {
case START:
if (io_bit_count == 0) {
io_bit_count = 16;
one_wire_status = REQUEST;
}
break;
case REQUEST:
// Send a bit
set_pin_value(io_data & (1U << 31));
io_data <<= 1;
if (io_bit_count == 0) {
io_bit_count = 2;
one_wire_status = WAITING;
}
break;
case WAITING:
if (io_bit_count == 0) {
io_bit_count = 32;
one_wire_status = RESPONSE;
}
if (io_bit_count == 1) {
set_pin_as_input();
set_pin_value(1);
}
break;
case RESPONSE:
// Get a bit
io_data = (io_data << 1) | get_pin_value();
if (io_bit_count == 0) {
io_bit_count = 2;
one_wire_status = STOPING;
set_pin_value(1);
set_pin_as_output();
one_wire_session_complete(one_wire_request, io_data);
}
break;
case STOPING:
if (io_bit_count == 0) {
one_wire_status = IDLE;
stop_timer_for_1wire();
}
break;
default:
stop_timer_for_1wire();
}
return IRQ_HANDLED;
}
#define S3C2410_TCON_T3RELOAD (1<<19)
#define S3C2410_TCON_T3MANUALUPD (1<<17)
static void start_one_wire_session(unsigned char req)
{
unsigned int tcon;
printk("backlight_write\n");
one_wire_status = START;
//gpio_set_value(one_write_pin, 1);
//pinctrl_select_state(pctrl, pstate_out);
set_pin_value(1);
set_pin_as_output();
// IDLE to START
{
unsigned char crc;
crc8_init(crc);
crc8(crc, req);
io_data = (req << 8) + crc;
io_data <<= 16;
}
io_bit_count = 1;
set_pin_as_output();
//pinctrl_select_state(pctrl, pstate_out);
timer->TCNTB3 = 650;
//init tranfer and start timer
tcon = timer->TCON;
tcon &= ~(0xF << 16);
tcon |= (1 << 17);
timer->TCON = tcon;
tcon |= (1 << 16);
tcon |= (1 << 19);
tcon &= ~(1 << 17);
timer->TCON = tcon;
timer->TINT_CSTAT |= 0x08;
//gpio_set_value(one_write_pin, 0);
set_pin_value(0);
}
static int backlight_open(struct inode * inode, struct file * file){
printk("%s enter.\n", __func__);
return 0;
}
static ssize_t backlight_write(struct file *file, const char *buffer, size_t count, loff_t * ppos)
{
int ret;
char buf[4] = {0, 0, 0, 0};
unsigned v;
unsigned len;
if (count == 0) {
return -EINVAL;
}
if (count > sizeof buf - 1) {
len = sizeof buf - 1;
} else {
len = count;
}
ret = copy_from_user(buf, buffer, len);
if (ret) {
return -EFAULT;
}
if (sscanf(buf, "%u", &v) != 1) {
return -EINVAL;
}
if (v > 127) {
v = 127;
}
bl_ready = 0;
backlight_req = v + 0x80U;
start_one_wire_session(backlight_req);
ret = wait_event_interruptible_timeout(bl_waitq, bl_ready, HZ / 10);
if (ret < 0) {
return ret;
}
if (ret == 0) {
return -ETIMEDOUT;
}
return count;
}
static int backlight_release(struct inode *inode, struct file *file){
devm_gpio_free(dev,onewrite_pin);
return 0;
}
static const struct file_operations gpj1_3_fops={
.owner = THIS_MODULE,
.open = backlight_open,
.write = backlight_write,
.release = backlight_release,
};
struct clk *clk=NULL;
static int pinctrl_probe(struct platform_device *pdev) {
int error,ret;
struct resource *res=NULL,*irq=NULL;
dev = &pdev->dev;
printk("%s enter.\n", __func__);
if (!dev->of_node) {
dev_err(dev, "no platform data.\n");
goto err0;
}
/*request resource*/
onewrite_pin=of_get_named_gpio(dev->of_node,"tiny4412,backlight",0);
devm_gpio_request_one(dev, onewrite_pin,GPIOF_OUT_INIT_HIGH,"onewrite_pin");
pinctrl=devm_pinctrl_get(dev);
pinctrl_out=pinctrl_lookup_state(pinctrl,"backlight_out");
pinctrl_in=pinctrl_lookup_state(pinctrl,"backlight_in");
res=platform_get_resource(pdev,IORESOURCE_MEM,0);
if(!res){
dev_err(dev, "failed to get timer base mem resource\n");
return -ENOMEM;
}
timer=devm_ioremap_resource(dev,res);
if(timer<0){
dev_err(dev, "failed to get timer base mem\n");
return -ENOMEM;
}
printk("p:\ttimer: %p\n",timer);
clk=devm_clk_get(dev,"timers");
if(IS_ERR(clk)){
dev_err(dev, "failed to get timer base clk\n");
return PTR_ERR(clk);
}
clk_prepare(clk);
//timer_debug;
timer->TCFG0 = 0xf00;
timer->TCFG1 = 0x10004;
error=init_timer_for_1wire(clk);
//error = clk_enable((clk));
if(error){
printk("init timer error");
return -1;
}
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (irq == NULL){
printk("platform_get_resource irq error\n");
return -EINVAL;
}
ret = devm_request_irq(dev, irq->start, timer_for_1wire_interrupt , IRQF_TIMER, "backlight", NULL);
if (ret)
{
dev_err(dev, "unable to request irq\n");
return -EINVAL;
}
timer->TINT_CSTAT=0x108;
/*create cdev*/
error=alloc_chrdev_region(&devid, 0, dev_num, "one_write");
if(error){
dev_err(dev, "alloc region failed.\n");
goto err0;
}
major = MAJOR(devid);
cdev_init(&gpj1_3_cdev, &gpj1_3_fops);
cdev_add(&gpj1_3_cdev, MKDEV(major, 0), dev_num);
gpj_class=class_create(THIS_MODULE,"gpj_1_3");
class_dev=device_create(gpj_class, NULL, devid, NULL, devname);
start_one_wire_session(0xf0);
//printk("after first session\n");
//timer_debug;
start_one_wire_session(0xf0);
//printk("after first session\n");
//timer_debug;
return 0;
err0:
return -EINVAL;
}
static int pinctrl_remove(struct platform_device *pdev) {
printk("%s enter.\n", __func__);
clk_enable(clk);
unregister_chrdev_region(devid,dev_num);
cdev_del(&gpj1_3_cdev);
device_destroy(gpj_class,MKDEV(major, 0));
class_destroy(gpj_class);
return 0;
}
static const struct of_device_id dt_ids[] = {
{ .compatible = "tiny4412,backlight_demo", },
{},
};
MODULE_DEVICE_TABLE(of, dt_ids);
static struct platform_driver backlight_driver = {
.driver = {
.name = "one_write",
.of_match_table = of_match_ptr(dt_ids),
},
.probe = pinctrl_probe,
.remove = pinctrl_remove,
};
static int backlight_init(void){
int ret;
printk("%s enter.\n", __func__);
ret = platform_driver_register(&backlight_driver);
if (ret)
printk(KERN_ERR "int demo: probe failed: %d\n", ret);
return ret;
}
static void backlight_exit(void){
printk("%s enter.\n", __func__);
platform_driver_unregister(&backlight_driver);
}
module_init(backlight_init);
module_exit(backlight_exit);
MODULE_LICENSE("GPL");
效果：