1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Renesas Emma Mobile 8250 driver 4 * 5 * Copyright (C) 2012 Magnus Damm 6 */ 7 8 #include <linux/device.h> 9 #include <linux/io.h> 10 #include <linux/module.h> 11 #include <linux/mod_devicetable.h> 12 #include <linux/serial_8250.h> 13 #include <linux/serial_reg.h> 14 #include <linux/platform_device.h> 15 #include <linux/clk.h> 16 #include <linux/slab.h> 17 18 #include "8250.h" 19 20 #define UART_DLL_EM 9 21 #define UART_DLM_EM 10 22 23 struct serial8250_em_priv { 24 struct clk *sclk; 25 int line; 26 }; 27 28 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) 29 { 30 switch (offset) { 31 case UART_TX: /* TX @ 0x00 */ 32 writeb(value, p->membase); 33 break; 34 case UART_FCR: /* FCR @ 0x0c (+1) */ 35 case UART_LCR: /* LCR @ 0x10 (+1) */ 36 case UART_MCR: /* MCR @ 0x14 (+1) */ 37 case UART_SCR: /* SCR @ 0x20 (+1) */ 38 writel(value, p->membase + ((offset + 1) << 2)); 39 break; 40 case UART_IER: /* IER @ 0x04 */ 41 value &= 0x0f; /* only 4 valid bits - not Xscale */ 42 fallthrough; 43 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 44 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 45 writel(value, p->membase + (offset << 2)); 46 } 47 } 48 49 static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) 50 { 51 switch (offset) { 52 case UART_RX: /* RX @ 0x00 */ 53 return readb(p->membase); 54 case UART_MCR: /* MCR @ 0x14 (+1) */ 55 case UART_LSR: /* LSR @ 0x18 (+1) */ 56 case UART_MSR: /* MSR @ 0x1c (+1) */ 57 case UART_SCR: /* SCR @ 0x20 (+1) */ 58 return readl(p->membase + ((offset + 1) << 2)); 59 case UART_IER: /* IER @ 0x04 */ 60 case UART_IIR: /* IIR @ 0x08 */ 61 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 62 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 63 return readl(p->membase + (offset << 2)); 64 } 65 return 0; 66 } 67 68 static int serial8250_em_serial_dl_read(struct uart_8250_port *up) 69 { 70 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; 71 } 72 73 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) 74 { 75 serial_out(up, UART_DLL_EM, value & 0xff); 76 serial_out(up, UART_DLM_EM, value >> 8 & 0xff); 77 } 78 79 static int serial8250_em_probe(struct platform_device *pdev) 80 { 81 struct serial8250_em_priv *priv; 82 struct uart_8250_port up; 83 struct resource *regs; 84 int irq, ret; 85 86 irq = platform_get_irq(pdev, 0); 87 if (irq < 0) 88 return irq; 89 90 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 91 if (!regs) { 92 dev_err(&pdev->dev, "missing registers\n"); 93 return -EINVAL; 94 } 95 96 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 97 if (!priv) 98 return -ENOMEM; 99 100 priv->sclk = devm_clk_get(&pdev->dev, "sclk"); 101 if (IS_ERR(priv->sclk)) { 102 dev_err(&pdev->dev, "unable to get clock\n"); 103 return PTR_ERR(priv->sclk); 104 } 105 106 memset(&up, 0, sizeof(up)); 107 up.port.mapbase = regs->start; 108 up.port.irq = irq; 109 up.port.type = PORT_UNKNOWN; 110 up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP; 111 up.port.dev = &pdev->dev; 112 up.port.private_data = priv; 113 114 clk_prepare_enable(priv->sclk); 115 up.port.uartclk = clk_get_rate(priv->sclk); 116 117 up.port.iotype = UPIO_MEM32; 118 up.port.serial_in = serial8250_em_serial_in; 119 up.port.serial_out = serial8250_em_serial_out; 120 up.dl_read = serial8250_em_serial_dl_read; 121 up.dl_write = serial8250_em_serial_dl_write; 122 123 ret = serial8250_register_8250_port(&up); 124 if (ret < 0) { 125 dev_err(&pdev->dev, "unable to register 8250 port\n"); 126 clk_disable_unprepare(priv->sclk); 127 return ret; 128 } 129 130 priv->line = ret; 131 platform_set_drvdata(pdev, priv); 132 return 0; 133 } 134 135 static int serial8250_em_remove(struct platform_device *pdev) 136 { 137 struct serial8250_em_priv *priv = platform_get_drvdata(pdev); 138 139 serial8250_unregister_port(priv->line); 140 clk_disable_unprepare(priv->sclk); 141 return 0; 142 } 143 144 static const struct of_device_id serial8250_em_dt_ids[] = { 145 { .compatible = "renesas,em-uart", }, 146 {}, 147 }; 148 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); 149 150 static struct platform_driver serial8250_em_platform_driver = { 151 .driver = { 152 .name = "serial8250-em", 153 .of_match_table = serial8250_em_dt_ids, 154 }, 155 .probe = serial8250_em_probe, 156 .remove = serial8250_em_remove, 157 }; 158 159 module_platform_driver(serial8250_em_platform_driver); 160 161 MODULE_AUTHOR("Magnus Damm"); 162 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); 163 MODULE_LICENSE("GPL v2"); 164