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 23 struct power_off_cfg { 24 u32 baud; 25 char cmd; 26 }; 27 28 static const struct power_off_cfg qnap_power_off_cfg = { 29 .baud = 19200, 30 .cmd = 'A', 31 }; 32 33 static const struct power_off_cfg synology_power_off_cfg = { 34 .baud = 9600, 35 .cmd = '1', 36 }; 37 38 static 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 }; 47 MODULE_DEVICE_TABLE(of, qnap_power_off_of_match_table); 48 49 static void __iomem *base; 50 static unsigned long tclk; 51 static const struct power_off_cfg *cfg; 52 53 static 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 72 static 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 } 113 114 static int qnap_power_off_remove(struct platform_device *pdev) 115 { 116 pm_power_off = NULL; 117 return 0; 118 } 119 120 static 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 }; 128 module_platform_driver(qnap_power_off_driver); 129 130 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); 131 MODULE_DESCRIPTION("QNAP Power off driver"); 132 MODULE_LICENSE("GPL v2"); 133