u-boot/drivers/bootcount/bootcount_dm_i2c.c
Philip Richard Oberfichtner 5b6ee512ce bootcount: Add driver model I2C driver
This adds a generic I2C bootcounter adhering to driver model to replace
the previously removed legacy implementation.

There is no change in functionality, it can be used on any I2C device.
The device tree configuration may look like this for example:

	bootcount {
		compatible = "u-boot,bootcount-i2c";
		i2cbcdev = <&i2c_rtc>;
		offset = <0x11>;
	};

Signed-off-by: Philip Richard Oberfichtner <pro@denx.de>
Reviewed-by: Heiko Schocher <hs@denx.de>
2023-10-31 09:09:04 +01:00

102 lines
2.1 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2023
* Philip Richard Oberfichtner <pro@denx.de>
*
* Based on previous work from Heiko Schocher (legacy bootcount_i2c.c driver)
*/
#include <bootcount.h>
#include <dm.h>
#include <i2c.h>
#define BC_MAGIC 0x55
struct bootcount_i2c_priv {
struct udevice *bcdev;
unsigned int offset;
};
static int bootcount_i2c_set(struct udevice *dev, const u32 val)
{
int ret;
struct bootcount_i2c_priv *priv = dev_get_priv(dev);
ret = dm_i2c_reg_write(priv->bcdev, priv->offset, BC_MAGIC);
if (ret < 0)
goto err_exit;
ret = dm_i2c_reg_write(priv->bcdev, priv->offset + 1, val & 0xff);
if (ret < 0)
goto err_exit;
return 0;
err_exit:
log_debug("%s: Error writing to I2C device (%d)\n", __func__, ret);
return ret;
}
static int bootcount_i2c_get(struct udevice *dev, u32 *val)
{
int ret;
struct bootcount_i2c_priv *priv = dev_get_priv(dev);
ret = dm_i2c_reg_read(priv->bcdev, priv->offset);
if (ret < 0)
goto err_exit;
if ((ret & 0xff) != BC_MAGIC) {
log_debug("%s: Invalid Magic, reset bootcounter.\n", __func__);
*val = 0;
return bootcount_i2c_set(dev, 0);
}
ret = dm_i2c_reg_read(priv->bcdev, priv->offset + 1);
if (ret < 0)
goto err_exit;
*val = ret;
return 0;
err_exit:
log_debug("%s: Error reading from I2C device (%d)\n", __func__, ret);
return ret;
}
static int bootcount_i2c_probe(struct udevice *dev)
{
struct bootcount_i2c_priv *priv = dev_get_priv(dev);
int ret;
ret = dev_read_u32(dev, "offset", &priv->offset);
if (ret)
goto exit;
ret = i2c_get_chip_by_phandle(dev, "i2cbcdev", &priv->bcdev);
exit:
if (ret)
log_debug("%s failed, ret = %d\n", __func__, ret);
return ret;
}
static const struct bootcount_ops bootcount_i2c_ops = {
.get = bootcount_i2c_get,
.set = bootcount_i2c_set,
};
static const struct udevice_id bootcount_i2c_ids[] = {
{ .compatible = "u-boot,bootcount-i2c" },
{ }
};
U_BOOT_DRIVER(bootcount_i2c) = {
.name = "bootcount-i2c",
.id = UCLASS_BOOTCOUNT,
.priv_auto = sizeof(struct bootcount_i2c_priv),
.probe = bootcount_i2c_probe,
.of_match = bootcount_i2c_ids,
.ops = &bootcount_i2c_ops,
};