137 lines
3.2 KiB
C
137 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* QNAP Turbo NAS Board power off. Can also be used on Synology devices.
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*
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* Copyright (C) 2012 Andrew Lunn <andrew@lunn.ch>
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*
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* Based on the code from:
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*
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* Copyright (C) 2009 Martin Michlmayr <tbm@cyrius.com>
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* Copyright (C) 2008 Byron Bradley <byron.bbradley@gmail.com>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/serial_reg.h>
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#include <linux/kallsyms.h>
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#include <linux/of.h>
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#include <linux/io.h>
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#include <linux/clk.h>
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#define UART1_REG(x) (base + ((UART_##x) << 2))
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struct power_off_cfg {
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u32 baud;
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char cmd;
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};
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static const struct power_off_cfg qnap_power_off_cfg = {
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.baud = 19200,
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.cmd = 'A',
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};
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static const struct power_off_cfg synology_power_off_cfg = {
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.baud = 9600,
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.cmd = '1',
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};
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static const struct of_device_id qnap_power_off_of_match_table[] = {
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{ .compatible = "qnap,power-off",
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.data = &qnap_power_off_cfg,
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},
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{ .compatible = "synology,power-off",
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.data = &synology_power_off_cfg,
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},
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{}
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};
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MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table);
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static void __iomem *base;
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static unsigned long tclk;
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static const struct power_off_cfg *cfg;
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static void qnap_power_off(void)
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{
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const unsigned divisor = ((tclk + (8 * cfg->baud)) / (16 * cfg->baud));
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pr_err("%s: triggering power-off...\n", __func__);
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/* hijack UART1 and reset into sane state */
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writel(0x83, UART1_REG(LCR));
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writel(divisor & 0xff, UART1_REG(DLL));
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writel((divisor >> 8) & 0xff, UART1_REG(DLM));
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writel(0x03, UART1_REG(LCR));
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writel(0x00, UART1_REG(IER));
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writel(0x00, UART1_REG(FCR));
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writel(0x00, UART1_REG(MCR));
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/* send the power-off command to PIC */
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writel(cfg->cmd, UART1_REG(TX));
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}
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static int qnap_power_off_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct resource *res;
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struct clk *clk;
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char symname[KSYM_NAME_LEN];
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const struct of_device_id *match =
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of_match_node(qnap_power_off_of_match_table, np);
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cfg = match->data;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "Missing resource");
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return -EINVAL;
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}
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base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
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if (!base) {
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dev_err(&pdev->dev, "Unable to map resource");
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return -EINVAL;
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}
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/* We need to know tclk in order to calculate the UART divisor */
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clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(clk)) {
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dev_err(&pdev->dev, "Clk missing");
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return PTR_ERR(clk);
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}
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tclk = clk_get_rate(clk);
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/* Check that nothing else has already setup a handler */
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if (pm_power_off) {
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lookup_symbol_name((ulong)pm_power_off, symname);
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dev_err(&pdev->dev,
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"pm_power_off already claimed %p %s",
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pm_power_off, symname);
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return -EBUSY;
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}
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pm_power_off = qnap_power_off;
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return 0;
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}
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static int qnap_power_off_remove(struct platform_device *pdev)
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{
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pm_power_off = NULL;
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return 0;
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}
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static struct platform_driver qnap_power_off_driver = {
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.probe = qnap_power_off_probe,
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.remove = qnap_power_off_remove,
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.driver = {
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.name = "qnap_power_off",
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.of_match_table = of_match_ptr(qnap_power_off_of_match_table),
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},
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};
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module_platform_driver(qnap_power_off_driver);
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MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
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MODULE_DESCRIPTION("QNAP Power off driver");
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MODULE_LICENSE("GPL v2");
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