LXR linux/drivers/power/reset/qnap-poweroff.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * QNAP Turbo NAS Board power off. Can also be used on Synology devices.
   4 *
   5 * Copyright (C) 2012 Andrew Lunn <andrew@lunn.ch>
   6 *
   7 * Based on the code from:
   8 *
   9 * Copyright (C) 2009  Martin Michlmayr <tbm@cyrius.com>
  10 * Copyright (C) 2008  Byron Bradley <byron.bbradley@gmail.com>
  11 */
  12
  13#include <linux/kernel.h>
  14#include <linux/module.h>
  15#include <linux/platform_device.h>
  16#include <linux/serial_reg.h>
  17#include <linux/of.h>
  18#include <linux/io.h>
  19#include <linux/clk.h>
  20
  21#define UART1_REG(x)    (base + ((UART_##x) << 2))
  22
  23struct power_off_cfg {
  24        u32 baud;
  25        char cmd;
  26};
  27
  28static const struct power_off_cfg qnap_power_off_cfg = {
  29        .baud = 19200,
  30        .cmd = 'A',
  31};
  32
  33static const struct power_off_cfg synology_power_off_cfg = {
  34        .baud = 9600,
  35        .cmd = '1',
  36};
  37
  38static const struct of_device_id qnap_power_off_of_match_table[] = {
  39        { .compatible = "qnap,power-off",
  40          .data = &qnap_power_off_cfg,
  41        },
  42        { .compatible = "synology,power-off",
  43          .data = &synology_power_off_cfg,
  44        },
  45        {}
  46};
  47MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table);
  48
  49static void __iomem *base;
  50static unsigned long tclk;
  51static const struct power_off_cfg *cfg;
  52
  53static void qnap_power_off(void)
  54{
  55        const unsigned divisor = ((tclk + (8 * cfg->baud)) / (16 * cfg->baud));
  56
  57        pr_err("%s: triggering power-off...\n", __func__);
  58
  59        /* hijack UART1 and reset into sane state */
  60        writel(0x83, UART1_REG(LCR));
  61        writel(divisor & 0xff, UART1_REG(DLL));
  62        writel((divisor >> 8) & 0xff, UART1_REG(DLM));
  63        writel(0x03, UART1_REG(LCR));
  64        writel(0x00, UART1_REG(IER));
  65        writel(0x00, UART1_REG(FCR));
  66        writel(0x00, UART1_REG(MCR));
  67
  68        /* send the power-off command to PIC */
  69        writel(cfg->cmd, UART1_REG(TX));
  70}
  71
  72static int qnap_power_off_probe(struct platform_device *pdev)
  73{
  74        struct device_node *np = pdev->dev.of_node;
  75        struct resource *res;
  76        struct clk *clk;
  77
  78        const struct of_device_id *match =
  79                of_match_node(qnap_power_off_of_match_table, np);
  80        cfg = match->data;
  81
  82        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  83        if (!res) {
  84                dev_err(&pdev->dev, "Missing resource");
  85                return -EINVAL;
  86        }
  87
  88        base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
  89        if (!base) {
  90                dev_err(&pdev->dev, "Unable to map resource");
  91                return -EINVAL;
  92        }
  93
  94        /* We need to know tclk in order to calculate the UART divisor */
  95        clk = devm_clk_get(&pdev->dev, NULL);
  96        if (IS_ERR(clk)) {
  97                dev_err(&pdev->dev, "Clk missing");
  98                return PTR_ERR(clk);
  99        }
 100
 101        tclk = clk_get_rate(clk);
 102
 103        /* Check that nothing else has already setup a handler */
 104        if (pm_power_off) {
 105                dev_err(&pdev->dev, "pm_power_off already claimed for %ps",
 106                        pm_power_off);
 107                return -EBUSY;
 108        }
 109        pm_power_off = qnap_power_off;
 110
 111        return 0;
 112}
 113
 114static int qnap_power_off_remove(struct platform_device *pdev)
 115{
 116        pm_power_off = NULL;
 117        return 0;
 118}
 119
 120static struct platform_driver qnap_power_off_driver = {
 121        .probe  = qnap_power_off_probe,
 122        .remove = qnap_power_off_remove,
 123        .driver = {
 124                .name   = "qnap_power_off",
 125                .of_match_table = of_match_ptr(qnap_power_off_of_match_table),
 126        },
 127};
 128module_platform_driver(qnap_power_off_driver);
 129
 130MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 131MODULE_DESCRIPTION("QNAP Power off driver");
 132MODULE_LICENSE("GPL v2");
 133