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openmptcprouter/6.7/package/kernel/r2ec/src/r2ec.c

752 lines
18 KiB
C

#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include "io.h"
static const struct i2c_device_id r2ec_id[] = {
{ "stm32v1", NO_OF_GPIOS },
{ }
};
MODULE_DEVICE_TABLE(i2c, r2ec_id);
static const struct of_device_id r2ec_of_table[] = {
{ .compatible = "tlt,stm32v1" },
{ }
};
MODULE_DEVICE_TABLE(of, r2ec_of_table);
static uint8_t g_proto;
struct r2ec {
struct gpio_chip chip;
struct irq_chip irqchip;
struct i2c_client *client;
struct mutex i2c_lock;
struct mutex irq_lock;
int ic_ready;
};
struct r2ec_platform_data {
unsigned gpio_base;
int (*setup)(struct i2c_client *client, int gpio, unsigned ngpio,
void *context);
int (*teardown)(struct i2c_client *client, int gpio, unsigned ngpio,
void *context);
void *context;
};
struct i2c_request {
uint8_t version;
uint16_t length;
uint8_t command;
uint8_t data[1];
// uint8_t checksum; // invisible
} __attribute__((packed));
struct i2c_response {
uint8_t version;
uint8_t length;
uint8_t command;
uint8_t data[7];
uint8_t checksum;
} __attribute__((packed));
static uint8_t calc_crc8(const uint8_t *data, size_t len)
{
uint8_t crc = 0xFF;
int i = 0;
int j = 0;
for (j = 0; j < len; j++) {
crc ^= data[j];
for (i = 0; i < 8; i++) {
crc = (crc & 0x80) ? (crc ^ 0xD5) << 1 : crc << 1;
}
}
return crc;
}
// generate outcoming mesage checksum and write i2c data
static int stm32_write(struct i2c_client *client, uint8_t ver, uint8_t cmd, uint8_t *data, size_t len)
{
struct i2c_request *req = NULL;
const int tmp_len = sizeof(struct i2c_request) + 1;
uint8_t tmp[sizeof(struct i2c_request) + 1];
int err = 0;
if (!client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
req = (struct i2c_request *)tmp;
req->version = ver;
req->length = 2 + len; // 2 + data_len
req->command = cmd;
memcpy(req->data, data, len);
req->data[len] = calc_crc8(tmp, tmp_len - 1);
if ((err = i2c_master_send(client, tmp, tmp_len)) < 0) {
return err;
}
return 0;
}
// attempt to read i2c data
static int stm32_read(struct i2c_client *client, uint8_t *data, size_t len)
{
char buffer[64] = { 0 };
uint8_t checksum;
int err;
unsigned i, cnt = 0;
if (!client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
retry:
if ((err = i2c_master_recv(client, data, len)) < 0) {
if (err == -ETIMEDOUT && cnt < 10) {
cnt++;
msleep(10);
goto retry;
}
return err;
}
if (len == 1) {
return 0;
}
// ignore checksum on partial i2c response
if (len == sizeof(struct i2c_response) - 1) {
return 0;
}
// 0xFF - no data available
if (*(data + 3) == 0xFF) {
return -ENODATA;
}
// generate checksum and verify
checksum = calc_crc8(data, len - 1);
if (checksum != *(data + len - 1)) {
for (i = 0; i < len; i++) {
snprintf(buffer + strlen(buffer), sizeof(buffer),
"%02X ", *(data + i));
}
dev_err(&client->dev, "Checksum of incoming message "
"does not match!\n"
"Received: %s\n", buffer);
// for some reason checksum might appear as 1st byte in the
// data buffer, and actual checksum byte is zero
// apply quirk - discard first byte, skip checksum checking
if (!*(data + len - 1)) {
dev_err(&client->dev,
"Applying wrong-checksum quirk...\n");
memmove(data, data + 1, len - 1);
return 0;
}
return -EBADE;
}
return 0;
}
// attempt to retrieve supported protocol version, then retrieve device state
// and boot into application state
// this is done without interrupt, so there should be delay after writing
// request and before reading response for protocol versions up until v2
static int stm32_prepare(struct r2ec *gpio, struct i2c_client *client)
{
struct i2c_response rsp;
uint8_t data[1], recv[1];
int ret;
memset(&rsp, 0, sizeof(rsp));
data[0] = PROTO_GET_SUPPORTED;
if ((ret = stm32_write(client, 1, CMD_PROTO, data, 1))) {
dev_err(&client->dev,
"stm32_prepare: proto version write failed (%d)\n",
ret);
return ret;
}
// due compatibility reasons delay is needed between write/read
// operations
msleep(10);
if ((ret = stm32_read(client, (uint8_t *)&rsp, sizeof(rsp)))) {
dev_err(&client->dev,
"stm32_prepare: proto version read failed (%d)\n", ret);
return ret;
}
g_proto = rsp.data[1];
// fallback to version 1
if (g_proto != PROTO_VERSION_1 && g_proto != PROTO_VERSION_2) {
printk("STM32 fallback protocol: %u\n", g_proto);
g_proto = PROTO_VERSION_1;
}
printk("STM32 supported protocol: %u\n", g_proto);
data[0] = BOOT_STATE;
if ((ret = stm32_write(client, g_proto, CMD_BOOT, data, 1))) {
dev_err(&client->dev,
"stm32_prepare: boot state write failed (%d)\n", ret);
return ret;
}
if ((ret = stm32_read(client, recv, 1))) {
dev_err(&client->dev,
"stm32_prepare: boot state read failed (%d)\n", ret);
return ret;
}
// device might be not ready aka in bootloader state
// we might need to ignore gpio_write status value
gpio->ic_ready = 0;
// handle the following possible states reported either from
// bootloader or system:
switch (recv[0]) {
case NO_IMAGE_FOUND:
case APP_STARTED:
// device is ready, no need to ignore gpio_write status value
// note: on no_image_found, user-space flasher will reflash
// firmware and device will be rebooted
gpio->ic_ready = 1;
return 0;
case BOOT_STARTED:
case WATCHDOG_RESET:
case APPLICATION_START_FAIL:
case HARD_FAULT_ERROR:
case NO_DATA_AVAILABLE:
break;
default:
dev_err(&client->dev, "Device did not responded with correct "
"state! Actual response was 0x%02X. "
"Unable to get device state!\n", recv[0]);
break;
}
data[0] = BOOT_START_APP;
if ((ret = stm32_write(client, g_proto, CMD_BOOT, data, 1))) {
dev_err(&client->dev,
"stm32_prepare: boot start write failed (%d)\n", ret);
return ret;
}
if ((ret = stm32_read(client, recv, 1))) {
dev_err(&client->dev,
"stm32_prepare: boot start read failed (%d)\n", ret);
return ret;
}
if (recv[0] != STATUS_ACK && recv[0] != NO_DATA_AVAILABLE) {
dev_err(&client->dev, "Device did not responded with ACK. "
"Actual response was 0x%02X. "
"Unable to set device state!\n", recv[0]);
return -EIO;
}
return 0;
}
static int stm32_gpio_write(struct r2ec *gpio, int pin, int val)
{
struct i2c_request *req;
size_t len = 2;
uint8_t tmp[sizeof(struct i2c_request) + 2];
//int err;
if (!gpio->client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
req = (struct i2c_request *)tmp;
req->version = PROTO_VERSION_2;
req->length = 2 + len; // command + crc + data
req->command = CMD_GPIO;
req->data[0] = pin;
req->data[1] = val;
i2c_master_send(gpio->client, tmp, sizeof(tmp));
// if ((err = i2c_master_send(gpio->client, tmp, sizeof(tmp))) < 0) {
// if (err != -ENXIO) {
// return err;
// }
// we need to ignore errors while device is not ready
// otherwise none of GPIOs/LEDs will be probed by the kernel
// if (!gpio->ic_ready) {
// err = 0;
// }
//
// return err;
// }
return 0;
}
static int stm32_gpio_read(struct r2ec *gpio, int pin, int val)
{
struct i2c_request *req;
size_t len = 2;
uint8_t tmp[sizeof(struct i2c_request) + 2];
uint8_t recv[1];
int err;
if (!gpio->client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
req = (struct i2c_request *)tmp;
req->version = PROTO_VERSION_2;
req->length = 2 + len; // command + crc + data
req->command = CMD_GPIO;
req->data[0] = pin;
req->data[1] = val;
if ((err = i2c_master_send(gpio->client, tmp, sizeof(tmp))) < 0) {
return err;
}
if ((err = i2c_master_recv(gpio->client, recv, sizeof(recv))) < 0) {
return err;
}
switch (recv[0]) {
case GPIO_STATE_HIGH:
return 1;
case GPIO_STATE_LOW:
return 0;
}
return -EIO;
}
static int r2ec_get(struct gpio_chip *chip, unsigned offset)
{
struct r2ec *gpio = gpiochip_get_data(chip);
int value;
mutex_lock(&gpio->i2c_lock);
value = stm32_gpio_read(gpio, offset, GPIO_VALUE_GET);
mutex_unlock(&gpio->i2c_lock);
return value;
}
static void r2ec_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct r2ec *gpio = gpiochip_get_data(chip);
int val = value ? GPIO_VALUE_SET_HIGH : GPIO_VALUE_SET_LOW;
mutex_lock(&gpio->i2c_lock);
stm32_gpio_write(gpio, offset, val);
mutex_unlock(&gpio->i2c_lock);
}
static int r2ec_input(struct gpio_chip *chip, unsigned offset)
{
struct r2ec *gpio = gpiochip_get_data(chip);
int status;
mutex_lock(&gpio->i2c_lock);
status = stm32_gpio_write(gpio, offset, GPIO_MODE_SET_INPUT);
mutex_unlock(&gpio->i2c_lock);
return status;
}
static int r2ec_output(struct gpio_chip *chip, unsigned offset, int value)
{
struct r2ec *gpio = gpiochip_get_data(chip);
int status;
mutex_lock(&gpio->i2c_lock);
status = stm32_gpio_write(gpio, offset, GPIO_MODE_SET_OUTPUT);
mutex_unlock(&gpio->i2c_lock);
r2ec_set(chip, offset, value);
return status;
}
static void noop(struct irq_data *data) { }
static int noop_wake(struct irq_data *data, unsigned on)
{
return 0;
}
static irqreturn_t r2ec_irq(int irq, void *data)
{
struct r2ec *gpio = data;
unsigned i;
for (i = 0; i < gpio->chip.ngpio; i++) {
handle_nested_irq(irq_find_mapping(gpio->chip.irq.domain, i));
}
return IRQ_HANDLED;
}
static void r2ec_irq_bus_lock(struct irq_data *data)
{
struct r2ec *gpio = irq_data_get_irq_chip_data(data);
mutex_lock(&gpio->irq_lock);
}
static void r2ec_irq_bus_sync_unlock(struct irq_data *data)
{
struct r2ec *gpio = irq_data_get_irq_chip_data(data);
mutex_unlock(&gpio->irq_lock);
}
static int chip_label_match(struct gpio_chip *chip, void *data)
{
return !strcmp(chip->label, data);
}
static int get_stm32_version(struct device *dev, uint8_t type, char *buffer)
{
struct gpio_chip *chip;
struct r2ec *gpio;
uint8_t recv[sizeof(struct i2c_response)];
uint8_t data[1];
int ret;
struct pt_fw_get_ver {
unsigned char command_ex;
unsigned char major;
unsigned char middle;
unsigned char minor;
unsigned char rev;
} __attribute__((packed)) *res;
chip = gpiochip_find("stm32v1", chip_label_match);
if (!chip) {
printk(KERN_ERR "Unable to find R2EC gpio chip!\n");
return -ENXIO;
}
gpio = gpiochip_get_data(chip);
if (!gpio->client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
data[0] = (type == CMD_FW) ? FW_VERSION : BOOT_VERSION;
mutex_lock(&gpio->i2c_lock);
if ((ret = stm32_write(gpio->client, g_proto, type, data, 1))) {
printk("%s: firmware version write failed (%d)\n",
__func__, ret);
goto done;
}
// prevent possible I2C bus lockup when master requests more than 1 byte
// and slave only sends a couple of bytes, but master is still waiting
// and SCL line is down; there is no recovery except power cycle
// first read 1 byte and compare with supported protocol versions
// if they match, then full messsage can be read, otherwise drop
// everything to not introduce bus lockup
if ((ret = stm32_read(gpio->client, data, 1))) {
printk("%s: firmware version read failed (%d)\n",
__func__, ret);
goto done;
}
if (data[0] != PROTO_VERSION_1 && data[0] != PROTO_VERSION_2) {
goto done;
}
recv[0] = data[0];
if ((ret = stm32_read(gpio->client, &recv[1], sizeof(recv) - 1))) {
printk("%s: firmware version read failed (%d)\n",
__func__, ret);
goto done;
}
// device is ready now, running in application-mode
// this is called by autoflasher script first time
if (!gpio->ic_ready) {
gpio->ic_ready = 1;
}
res = (struct pt_fw_get_ver *)(&recv[3]);
sprintf(buffer, "%02d.%02d.%02d rev. %02d\n",
res->major, res->middle, res->minor, res->rev);
done:
mutex_unlock(&gpio->i2c_lock);
return strlen(buffer);
}
static ssize_t app_version_show(struct device *dev,
struct device_attribute *attr, char *buffer)
{
return get_stm32_version(dev, CMD_FW, buffer);
}
static ssize_t boot_version_show(struct device *dev,
struct device_attribute *attr, char *buffer)
{
return get_stm32_version(dev, CMD_BOOT, buffer);
}
static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
const char *buff, size_t count)
{
struct gpio_chip *chip;
struct r2ec *gpio;
uint8_t data[1];
chip = gpiochip_find("stm32v1", chip_label_match);
if (!chip) {
printk(KERN_ERR "Unable to find R2EC gpio chip!\n");
return -ENXIO;
}
gpio = gpiochip_get_data(chip);
if (!gpio->client) {
printk(KERN_ERR "R2EC I2C client is not ready!\n");
return -ENXIO;
}
data[0] = BOOT_START_APP;
mutex_lock(&gpio->i2c_lock);
if (stm32_write(gpio->client, g_proto, CMD_BOOT, data, 1)) {
printk(KERN_ERR "Unable transmit R2EC data!\n");
goto done;
}
done:
mutex_unlock(&gpio->i2c_lock);
return 1;
}
static struct device_attribute g_r2ec_kobj_attr[] = {
__ATTR_RO(app_version),
__ATTR_RO(boot_version),
__ATTR_WO(reset)
};
static struct attribute *g_r2ec_attrs[] = {
&g_r2ec_kobj_attr[0].attr,
&g_r2ec_kobj_attr[1].attr,
&g_r2ec_kobj_attr[2].attr,
NULL,
};
static struct attribute_group g_r2ec_attr_group = { .attrs = g_r2ec_attrs };
static struct kobject *g_r2ec_kobj;
static int r2ec_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct r2ec_platform_data *pdata = dev_get_platdata(&client->dev);
// dev_err(&client->dev,
// "r2ec_probe: dev_get_platdata(0x%x, %s): 0x%x\n",
// client->addr, client->name, pdata);
struct r2ec *gpio;
struct gpio_irq_chip *girq;
int status, i;
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio) {
return -ENOMEM;
}
for (i = 0; i < 10; i++) {
if (!(status = stm32_prepare(gpio, client))) {
break;
}
dev_err(&client->dev,
"Unable to initialize device, retrying...\n");
// give some time for next interation...
msleep(500);
}
if (status) {
dev_err(&client->dev, "Unable to initialize device!\n");
devm_kfree(&client->dev, gpio);
return status;
}
mutex_init(&gpio->irq_lock);
mutex_init(&gpio->i2c_lock);
lockdep_set_subclass(&gpio->i2c_lock,
i2c_adapter_depth(client->adapter));
gpio->chip.base = pdata ? pdata->gpio_base : -1;
gpio->chip.can_sleep = true;
gpio->chip.parent = &client->dev;
gpio->chip.owner = THIS_MODULE;
gpio->chip.get = r2ec_get;
gpio->chip.set = r2ec_set;
gpio->chip.direction_input = r2ec_input;
gpio->chip.direction_output = r2ec_output;
gpio->chip.ngpio = id->driver_data;
gpio->chip.label = client->name;
gpio->client = client;
i2c_set_clientdata(client, gpio);
if (client->irq) {
gpio->irqchip.name = "r2ec";
gpio->irqchip.irq_enable = noop,
gpio->irqchip.irq_disable = noop,
gpio->irqchip.irq_ack = noop,
gpio->irqchip.irq_mask = noop,
gpio->irqchip.irq_unmask = noop,
gpio->irqchip.irq_set_wake = noop_wake,
gpio->irqchip.irq_bus_lock = r2ec_irq_bus_lock;
gpio->irqchip.irq_bus_sync_unlock = r2ec_irq_bus_sync_unlock;
girq = &gpio->chip.irq;
girq->chip = &gpio->irqchip;
/* This will let us handle the parent IRQ in the driver */
girq->parent_handler = NULL;
girq->num_parents = 0;
girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_bad_irq;
girq->threaded = true;
status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
if (status) {
dev_err(&client->dev, "cannot add irqchip\n");
goto fail;
}
status = devm_request_threaded_irq(&client->dev, client->irq,
NULL, r2ec_irq,
IRQF_ONESHOT |
IRQF_TRIGGER_FALLING |
IRQF_SHARED,
dev_name(&client->dev),
gpio);
if (status) {
goto fail;
}
}
if (pdata && pdata->setup) {
status = pdata->setup(client, gpio->chip.base, gpio->chip.ngpio,
pdata->context);
if (status < 0) {
dev_warn(&client->dev, "setup --> %d\n", status);
}
}
dev_info(&client->dev, "probed\n");
return 0;
fail:
devm_kfree(&client->dev, gpio);
dev_dbg(&client->dev, "probe error %d for %s\n", status, client->name);
return status;
}
static void r2ec_remove(struct i2c_client *client)
{
struct r2ec_platform_data *pdata = dev_get_platdata(&client->dev);
struct r2ec *gpio = i2c_get_clientdata(client);
int status = 0;
if (pdata && pdata->teardown) {
status = pdata->teardown(client, gpio->chip.base, gpio->chip.ngpio,
pdata->context);
if (status < 0) {
dev_err(&client->dev, "%s --> %d\n", "teardown", status);
}
}
}
static struct i2c_driver r2ec_driver = {
.driver = {
.name = "r2ec",
.of_match_table = of_match_ptr(r2ec_of_table),
},
.probe = r2ec_probe,
.remove = r2ec_remove,
.id_table = r2ec_id,
};
static int __init r2ec_init(void)
{
int ret;
ret = i2c_add_driver(&r2ec_driver);
if (ret) {
printk(KERN_ERR "Unable to initialize `r2ec` driver!\n");
return ret;
}
g_r2ec_kobj = kobject_create_and_add("r2ec", NULL);
if (!g_r2ec_kobj) {
i2c_del_driver(&r2ec_driver);
printk(KERN_ERR "Unable to create `r2ec` kobject!\n");
return -ENOMEM;
}
if (sysfs_create_group(g_r2ec_kobj, &g_r2ec_attr_group)) {
kobject_put(g_r2ec_kobj);
i2c_del_driver(&r2ec_driver);
printk(KERN_ERR "Unable to create `r2ec` sysfs group!\n");
return -ENOMEM;
}
return 0;
}
static void __exit r2ec_exit(void)
{
kobject_put(g_r2ec_kobj);
i2c_del_driver(&r2ec_driver);
}
module_init(r2ec_init);
module_exit(r2ec_exit);
MODULE_AUTHOR("Jokubas Maciulaitis <jokubas.maciulaitis@teltonika.lt>");
MODULE_DESCRIPTION("STM32F0 (R2EC) I2C GPIO Expander driver");
MODULE_LICENSE("GPL v2");