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/kallsyms.h>
  18#include <linux/of.h>
  19#include <linux/io.h>
  20#include <linux/clk.h>
  21
  22#define UART1_REG(x)    (base + ((UART_##x) << 2))
  23
  24struct power_off_cfg {
  25        u32 baud;
  26        char cmd;
  27};
  28
  29static const struct power_off_cfg qnap_power_off_cfg = {
  30        .baud = 19200,
  31        .cmd = 'A',
  32};
  33
  34static const struct power_off_cfg synology_power_off_cfg = {
  35        .baud = 9600,
  36        .cmd = '1',
  37};
  38
  39static const struct of_device_id qnap_power_off_of_match_table[] = {
  40        { .compatible = "qnap,power-off",
  41          .data = &qnap_power_off_cfg,
  42        },
  43        { .compatible = "synology,power-off",
  44          .data = &synology_power_off_cfg,
  45        },
  46        {}
  47};
  48MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table);
  49
  50static void __iomem *base;
  51static unsigned long tclk;
  52static const struct power_off_cfg *cfg;
  53
  54static void qnap_power_off(void)
  55{
  56        const unsigned divisor = ((tclk + (8 * cfg->baud)) / (16 * cfg->baud));
  57
  58        pr_err("%s: triggering power-off...\n", __func__);
  59
  60        /* hijack UART1 and reset into sane state */
  61        writel(0x83, UART1_REG(LCR));
  62        writel(divisor & 0xff, UART1_REG(DLL));
  63        writel((divisor >> 8) & 0xff, UART1_REG(DLM));
  64        writel(0x03, UART1_REG(LCR));
  65        writel(0x00, UART1_REG(IER));
  66        writel(0x00, UART1_REG(FCR));
  67        writel(0x00, UART1_REG(MCR));
  68
  69        /* send the power-off command to PIC */
  70        writel(cfg->cmd, UART1_REG(TX));
  71}
  72
  73static int qnap_power_off_probe(struct platform_device *pdev)
  74{
  75        struct device_node *np = pdev->dev.of_node;
  76        struct resource *res;
  77        struct clk *clk;
  78        char symname[KSYM_NAME_LEN];
  79
  80        const struct of_device_id *match =
  81                of_match_node(qnap_power_off_of_match_table, np);
  82        cfg = match->data;
  83
  84        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  85        if (!res) {
  86                dev_err(&pdev->dev, "Missing resource");
  87                return -EINVAL;
  88        }
  89
  90        base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
  91        if (!base) {
  92                dev_err(&pdev->dev, "Unable to map resource");
  93                return -EINVAL;
  94        }
  95
  96        /* We need to know tclk in order to calculate the UART divisor */
  97        clk = devm_clk_get(&pdev->dev, NULL);
  98        if (IS_ERR(clk)) {
  99                dev_err(&pdev->dev, "Clk missing");
 100                return PTR_ERR(clk);
 101        }
 102
 103        tclk = clk_get_rate(clk);
 104
 105        /* Check that nothing else has already setup a handler */
 106        if (pm_power_off) {
 107                lookup_symbol_name((ulong)pm_power_off, symname);
 108                dev_err(&pdev->dev,
 109                        "pm_power_off already claimed %p %s",
 110                        pm_power_off, symname);
 111                return -EBUSY;
 112        }
 113        pm_power_off = qnap_power_off;
 114
 115        return 0;
 116}
 117
 118static int qnap_power_off_remove(struct platform_device *pdev)
 119{
 120        pm_power_off = NULL;
 121        return 0;
 122}
 123
 124static struct platform_driver qnap_power_off_driver = {
 125        .probe  = qnap_power_off_probe,
 126        .remove = qnap_power_off_remove,
 127        .driver = {
 128                .name   = "qnap_power_off",
 129                .of_match_table = of_match_ptr(qnap_power_off_of_match_table),
 130        },
 131};
 132module_platform_driver(qnap_power_off_driver);
 133
 134MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 135MODULE_DESCRIPTION("QNAP Power off driver");
 136MODULE_LICENSE("GPL v2");
 137