1 /* 2 * QNAP Turbo NAS Board power off. Can also be used on Synology devices. 3 * 4 * Copyright (C) 2012 Andrew Lunn <andrew@lunn.ch> 5 * 6 * Based on the code from: 7 * 8 * Copyright (C) 2009 Martin Michlmayr <tbm@cyrius.com> 9 * Copyright (C) 2008 Byron Bradley <byron.bbradley@gmail.com> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/platform_device.h> 20 #include <linux/serial_reg.h> 21 #include <linux/kallsyms.h> 22 #include <linux/of.h> 23 #include <linux/io.h> 24 #include <linux/clk.h> 25 26 #define UART1_REG(x) (base + ((UART_##x) << 2)) 27 28 struct power_off_cfg { 29 u32 baud; 30 char cmd; 31 }; 32 33 static const struct power_off_cfg qnap_power_off_cfg = { 34 .baud = 19200, 35 .cmd = 'A', 36 }; 37 38 static const struct power_off_cfg synology_power_off_cfg = { 39 .baud = 9600, 40 .cmd = '1', 41 }; 42 43 static const struct of_device_id qnap_power_off_of_match_table[] = { 44 { .compatible = "qnap,power-off", 45 .data = &qnap_power_off_cfg, 46 }, 47 { .compatible = "synology,power-off", 48 .data = &synology_power_off_cfg, 49 }, 50 {} 51 }; 52 MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table); 53 54 static void __iomem *base; 55 static unsigned long tclk; 56 static const struct power_off_cfg *cfg; 57 58 static void qnap_power_off(void) 59 { 60 const unsigned divisor = ((tclk + (8 * cfg->baud)) / (16 * cfg->baud)); 61 62 pr_err("%s: triggering power-off...\n", __func__); 63 64 /* hijack UART1 and reset into sane state */ 65 writel(0x83, UART1_REG(LCR)); 66 writel(divisor & 0xff, UART1_REG(DLL)); 67 writel((divisor >> 8) & 0xff, UART1_REG(DLM)); 68 writel(0x03, UART1_REG(LCR)); 69 writel(0x00, UART1_REG(IER)); 70 writel(0x00, UART1_REG(FCR)); 71 writel(0x00, UART1_REG(MCR)); 72 73 /* send the power-off command to PIC */ 74 writel(cfg->cmd, UART1_REG(TX)); 75 } 76 77 static int qnap_power_off_probe(struct platform_device *pdev) 78 { 79 struct device_node *np = pdev->dev.of_node; 80 struct resource *res; 81 struct clk *clk; 82 char symname[KSYM_NAME_LEN]; 83 84 const struct of_device_id *match = 85 of_match_node(qnap_power_off_of_match_table, np); 86 cfg = match->data; 87 88 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 89 if (!res) { 90 dev_err(&pdev->dev, "Missing resource"); 91 return -EINVAL; 92 } 93 94 base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); 95 if (!base) { 96 dev_err(&pdev->dev, "Unable to map resource"); 97 return -EINVAL; 98 } 99 100 /* We need to know tclk in order to calculate the UART divisor */ 101 clk = devm_clk_get(&pdev->dev, NULL); 102 if (IS_ERR(clk)) { 103 dev_err(&pdev->dev, "Clk missing"); 104 return PTR_ERR(clk); 105 } 106 107 tclk = clk_get_rate(clk); 108 109 /* Check that nothing else has already setup a handler */ 110 if (pm_power_off) { 111 lookup_symbol_name((ulong)pm_power_off, symname); 112 dev_err(&pdev->dev, 113 "pm_power_off already claimed %p %s", 114 pm_power_off, symname); 115 return -EBUSY; 116 } 117 pm_power_off = qnap_power_off; 118 119 return 0; 120 } 121 122 static int qnap_power_off_remove(struct platform_device *pdev) 123 { 124 pm_power_off = NULL; 125 return 0; 126 } 127 128 static struct platform_driver qnap_power_off_driver = { 129 .probe = qnap_power_off_probe, 130 .remove = qnap_power_off_remove, 131 .driver = { 132 .name = "qnap_power_off", 133 .of_match_table = of_match_ptr(qnap_power_off_of_match_table), 134 }, 135 }; 136 module_platform_driver(qnap_power_off_driver); 137 138 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); 139 MODULE_DESCRIPTION("QNAP Power off driver"); 140 MODULE_LICENSE("GPL v2"); 141