diff options
Diffstat (limited to 'drivers/power/reset/qnap-poweroff.c')
| -rw-r--r-- | drivers/power/reset/qnap-poweroff.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/power/reset/qnap-poweroff.c b/drivers/power/reset/qnap-poweroff.c new file mode 100644 index 000000000000..37f56f7ee926 --- /dev/null +++ b/drivers/power/reset/qnap-poweroff.c @@ -0,0 +1,116 @@ +/* + * QNAP Turbo NAS Board power off + * + * Copyright (C) 2012 Andrew Lunn <andrew@lunn.ch> + * + * Based on the code from: + * + * Copyright (C) 2009 Martin Michlmayr <tbm@cyrius.com> + * Copyright (C) 2008 Byron Bradley <byron.bbradley@gmail.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/serial_reg.h> +#include <linux/kallsyms.h> +#include <linux/of.h> +#include <linux/io.h> +#include <linux/clk.h> + +#define UART1_REG(x) (base + ((UART_##x) << 2)) + +static void __iomem *base; +static unsigned long tclk; + +static void qnap_power_off(void) +{ + /* 19200 baud divisor */ + const unsigned divisor = ((tclk + (8 * 19200)) / (16 * 19200)); + + pr_err("%s: triggering power-off...\n", __func__); + + /* hijack UART1 and reset into sane state (19200,8n1) */ + writel(0x83, UART1_REG(LCR)); + writel(divisor & 0xff, UART1_REG(DLL)); + writel((divisor >> 8) & 0xff, UART1_REG(DLM)); + writel(0x03, UART1_REG(LCR)); + writel(0x00, UART1_REG(IER)); + writel(0x00, UART1_REG(FCR)); + writel(0x00, UART1_REG(MCR)); + + /* send the power-off command 'A' to PIC */ + writel('A', UART1_REG(TX)); +} + +static int qnap_power_off_probe(struct platform_device *pdev) +{ + struct resource *res; + struct clk *clk; + char symname[KSYM_NAME_LEN]; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "Missing resource"); + return -EINVAL; + } + + base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (!base) { + dev_err(&pdev->dev, "Unable to map resource"); + return -EINVAL; + } + + /* We need to know tclk in order to calculate the UART divisor */ + clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + dev_err(&pdev->dev, "Clk missing"); + return PTR_ERR(clk); + } + + tclk = clk_get_rate(clk); + + /* Check that nothing else has already setup a handler */ + if (pm_power_off) { + lookup_symbol_name((ulong)pm_power_off, symname); + dev_err(&pdev->dev, + "pm_power_off already claimed %p %s", + pm_power_off, symname); + return -EBUSY; + } + pm_power_off = qnap_power_off; + + return 0; +} + +static int qnap_power_off_remove(struct platform_device *pdev) +{ + pm_power_off = NULL; + return 0; +} + +static const struct of_device_id qnap_power_off_of_match_table[] = { + { .compatible = "qnap,power-off", }, + {} +}; +MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table); + +static struct platform_driver qnap_power_off_driver = { + .probe = qnap_power_off_probe, + .remove = qnap_power_off_remove, + .driver = { + .owner = THIS_MODULE, + .name = "qnap_power_off", + .of_match_table = of_match_ptr(qnap_power_off_of_match_table), + }, +}; +module_platform_driver(qnap_power_off_driver); + +MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); +MODULE_DESCRIPTION("QNAP Power off driver"); +MODULE_LICENSE("GPL v2"); |