u-boot/drivers/rtc/i2c_rtc_emul.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Simulate an I2C real time clock
*
* Copyright (c) 2015 Google, Inc
* Written by Simon Glass <sjg@chromium.org>
*/
/*
* This is a test driver. It starts off with the current time of the machine,
* but also supports setting the time, using an offset from the current
* clock. This driver is only intended for testing, not accurate
* time-keeping. It does not change the system time.
*/
#include <common.h>
#include <dm.h>
#include <i2c.h>
#include <os.h>
#include <rtc.h>
#include <asm/rtc.h>
#include <asm/test.h>
#ifdef DEBUG
#define debug_buffer print_buffer
#else
#define debug_buffer(x, ...)
#endif
/**
* struct sandbox_i2c_rtc_plat_data - platform data for the RTC
*
* @base_time: Base system time when RTC device was bound
* @offset: RTC offset from current system time
* @use_system_time: true to use system time, false to use @base_time
* @reg: Register values
*/
struct sandbox_i2c_rtc_plat_data {
long base_time;
long offset;
bool use_system_time;
u8 reg[REG_COUNT];
};
struct sandbox_i2c_rtc {
unsigned int offset_secs;
};
long sandbox_i2c_rtc_set_offset(struct udevice *dev, bool use_system_time,
int offset)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
long old_offset;
old_offset = plat->offset;
plat->use_system_time = use_system_time;
if (offset != -1)
plat->offset = offset;
return old_offset;
}
long sandbox_i2c_rtc_get_set_base_time(struct udevice *dev, long base_time)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
long old_base_time;
old_base_time = plat->base_time;
if (base_time != -1)
plat->base_time = base_time;
return old_base_time;
}
static void reset_time(struct udevice *dev)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
struct rtc_time now;
os_localtime(&now);
plat->base_time = rtc_mktime(&now);
plat->offset = 0;
plat->use_system_time = true;
}
static int sandbox_i2c_rtc_get(struct udevice *dev, struct rtc_time *time)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
struct rtc_time tm_now;
long now;
if (plat->use_system_time) {
os_localtime(&tm_now);
now = rtc_mktime(&tm_now);
} else {
now = plat->base_time;
}
return rtc_to_tm(now + plat->offset, time);
}
static int sandbox_i2c_rtc_set(struct udevice *dev, const struct rtc_time *time)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(dev);
struct rtc_time tm_now;
long now;
if (plat->use_system_time) {
os_localtime(&tm_now);
now = rtc_mktime(&tm_now);
} else {
now = plat->base_time;
}
plat->offset = rtc_mktime(time) - now;
return 0;
}
/* Update the current time in the registers */
static int sandbox_i2c_rtc_prepare_read(struct udevice *emul)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
struct rtc_time time;
int ret;
ret = sandbox_i2c_rtc_get(emul, &time);
if (ret)
return ret;
plat->reg[REG_SEC] = time.tm_sec;
plat->reg[REG_MIN] = time.tm_min;
plat->reg[REG_HOUR] = time.tm_hour;
plat->reg[REG_MDAY] = time.tm_mday;
plat->reg[REG_MON] = time.tm_mon;
plat->reg[REG_YEAR] = time.tm_year - 1900;
plat->reg[REG_WDAY] = time.tm_wday;
return 0;
}
static int sandbox_i2c_rtc_complete_write(struct udevice *emul)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
struct rtc_time time;
int ret;
time.tm_sec = plat->reg[REG_SEC];
time.tm_min = plat->reg[REG_MIN];
time.tm_hour = plat->reg[REG_HOUR];
time.tm_mday = plat->reg[REG_MDAY];
time.tm_mon = plat->reg[REG_MON];
time.tm_year = plat->reg[REG_YEAR] + 1900;
time.tm_wday = plat->reg[REG_WDAY];
ret = sandbox_i2c_rtc_set(emul, &time);
if (ret)
return ret;
return 0;
}
static int sandbox_i2c_rtc_xfer(struct udevice *emul, struct i2c_msg *msg,
int nmsgs)
{
struct sandbox_i2c_rtc_plat_data *plat = dev_get_platdata(emul);
uint offset = 0;
int ret;
debug("\n%s\n", __func__);
ret = sandbox_i2c_rtc_prepare_read(emul);
if (ret)
return ret;
for (; nmsgs > 0; nmsgs--, msg++) {
int len;
u8 *ptr;
len = msg->len;
debug(" %s: msg->len=%d",
msg->flags & I2C_M_RD ? "read" : "write",
msg->len);
if (msg->flags & I2C_M_RD) {
debug(", offset %x, len %x: ", offset, len);
/* Read the register */
memcpy(msg->buf, plat->reg + offset, len);
memset(msg->buf + len, '\xff', msg->len - len);
debug_buffer(0, msg->buf, 1, msg->len, 0);
} else if (len >= 1) {
ptr = msg->buf;
offset = *ptr++ & (REG_COUNT - 1);
len--;
debug(", set offset %x: ", offset);
debug_buffer(0, msg->buf, 1, msg->len, 0);
/* Write the register */
memcpy(plat->reg + offset, ptr, len);
if (offset == REG_RESET)
reset_time(emul);
}
}
ret = sandbox_i2c_rtc_complete_write(emul);
if (ret)
return ret;
return 0;
}
struct dm_i2c_ops sandbox_i2c_rtc_emul_ops = {
.xfer = sandbox_i2c_rtc_xfer,
};
static int sandbox_i2c_rtc_bind(struct udevice *dev)
{
reset_time(dev);
return 0;
}
static const struct udevice_id sandbox_i2c_rtc_ids[] = {
{ .compatible = "sandbox,i2c-rtc" },
{ }
};
U_BOOT_DRIVER(sandbox_i2c_rtc_emul) = {
.name = "sandbox_i2c_rtc_emul",
.id = UCLASS_I2C_EMUL,
.of_match = sandbox_i2c_rtc_ids,
.bind = sandbox_i2c_rtc_bind,
.priv_auto_alloc_size = sizeof(struct sandbox_i2c_rtc),
.platdata_auto_alloc_size = sizeof(struct sandbox_i2c_rtc_plat_data),
.ops = &sandbox_i2c_rtc_emul_ops,
};