linux-imx

// SPDX-License-Identifier: GPL-2.0-only

/*

 * drivers/hwmon/nsa320-hwmon.c

 *

 * ZyXEL NSA320 Media Servers

 * hardware monitoring

 *

 * Copyright (C) 2016 Adam Baker <linux@baker-net.org.uk>

 * based on a board file driver

 * Copyright (C) 2012 Peter Schildmann <linux@schildmann.info>

 */

​

#include <linux/bitops.h>

#include <linux/delay.h>

#include <linux/err.h>

#include <linux/gpio/consumer.h>

#include <linux/hwmon.h>

#include <linux/hwmon-sysfs.h>

#include <linux/jiffies.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_platform.h>

#include <linux/platform_device.h>

​

/* Tests for error return values rely upon this value being < 0x80 */

#define MAGIC_NUMBER 0x55

​

/*

 * The Zyxel hwmon MCU is a Holtek HT46R065 that is factory programmed

 * to perform temperature and fan speed monitoring. It is read by taking

 * the active pin low. The 32 bit output word is then clocked onto the

 * data line. The MSB of the data word is a magic nuber to indicate it

 * has been read correctly, the next byte is the fan speed (in hundreds

 * of RPM) and the last two bytes are the temperature (in tenths of a

 * degree)

 */

​

struct nsa320_hwmon {

    struct mutex        update_lock;    /* lock GPIO operations */

    unsigned long       last_updated;   /* jiffies */

    unsigned long       mcu_data;

    struct gpio_desc    *act;

    struct gpio_desc    *clk;

    struct gpio_desc    *data;

};

​

enum nsa320_inputs {

    NSA320_TEMP = 0,

    NSA320_FAN = 1,

};

​

static const char * const nsa320_input_names[] = {

    [NSA320_TEMP] = "System Temperature",

    [NSA320_FAN] = "Chassis Fan",

};

​

/*

 * Although this protocol looks similar to SPI the long delay

 * between the active (aka chip select) signal and the shorter

 * delay between clock pulses are needed for reliable operation.

 * The delays provided are taken from the manufacturer kernel,