1 /* 2 * Renesas Emma Mobile 8250 driver 3 * 4 * Copyright (C) 2012 Magnus Damm 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 20 #include <linux/device.h> 21 #include <linux/io.h> 22 #include <linux/module.h> 23 #include <linux/serial_8250.h> 24 #include <linux/serial_core.h> 25 #include <linux/serial_reg.h> 26 #include <linux/platform_device.h> 27 #include <linux/clk.h> 28 #include <linux/slab.h> 29 30 #include "8250.h" 31 32 #define UART_DLL_EM 9 33 #define UART_DLM_EM 10 34 35 struct serial8250_em_priv { 36 struct clk *sclk; 37 int line; 38 }; 39 40 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) 41 { 42 switch (offset) { 43 case UART_TX: /* TX @ 0x00 */ 44 writeb(value, p->membase); 45 break; 46 case UART_FCR: /* FCR @ 0x0c (+1) */ 47 case UART_LCR: /* LCR @ 0x10 (+1) */ 48 case UART_MCR: /* MCR @ 0x14 (+1) */ 49 case UART_SCR: /* SCR @ 0x20 (+1) */ 50 writel(value, p->membase + ((offset + 1) << 2)); 51 break; 52 case UART_IER: /* IER @ 0x04 */ 53 value &= 0x0f; /* only 4 valid bits - not Xscale */ 54 /* fall-through */ 55 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 56 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 57 writel(value, p->membase + (offset << 2)); 58 } 59 } 60 61 static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) 62 { 63 switch (offset) { 64 case UART_RX: /* RX @ 0x00 */ 65 return readb(p->membase); 66 case UART_MCR: /* MCR @ 0x14 (+1) */ 67 case UART_LSR: /* LSR @ 0x18 (+1) */ 68 case UART_MSR: /* MSR @ 0x1c (+1) */ 69 case UART_SCR: /* SCR @ 0x20 (+1) */ 70 return readl(p->membase + ((offset + 1) << 2)); 71 case UART_IER: /* IER @ 0x04 */ 72 case UART_IIR: /* IIR @ 0x08 */ 73 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 74 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 75 return readl(p->membase + (offset << 2)); 76 } 77 return 0; 78 } 79 80 static int serial8250_em_serial_dl_read(struct uart_8250_port *up) 81 { 82 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; 83 } 84 85 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) 86 { 87 serial_out(up, UART_DLL_EM, value & 0xff); 88 serial_out(up, UART_DLM_EM, value >> 8 & 0xff); 89 } 90 91 static int serial8250_em_probe(struct platform_device *pdev) 92 { 93 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 94 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 95 struct serial8250_em_priv *priv; 96 struct uart_8250_port up; 97 int ret; 98 99 if (!regs || !irq) { 100 dev_err(&pdev->dev, "missing registers or irq\n"); 101 return -EINVAL; 102 } 103 104 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 105 if (!priv) 106 return -ENOMEM; 107 108 priv->sclk = devm_clk_get(&pdev->dev, "sclk"); 109 if (IS_ERR(priv->sclk)) { 110 dev_err(&pdev->dev, "unable to get clock\n"); 111 return PTR_ERR(priv->sclk); 112 } 113 114 memset(&up, 0, sizeof(up)); 115 up.port.mapbase = regs->start; 116 up.port.irq = irq->start; 117 up.port.type = PORT_UNKNOWN; 118 up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP; 119 up.port.dev = &pdev->dev; 120 up.port.private_data = priv; 121 122 clk_prepare_enable(priv->sclk); 123 up.port.uartclk = clk_get_rate(priv->sclk); 124 125 up.port.iotype = UPIO_MEM32; 126 up.port.serial_in = serial8250_em_serial_in; 127 up.port.serial_out = serial8250_em_serial_out; 128 up.dl_read = serial8250_em_serial_dl_read; 129 up.dl_write = serial8250_em_serial_dl_write; 130 131 ret = serial8250_register_8250_port(&up); 132 if (ret < 0) { 133 dev_err(&pdev->dev, "unable to register 8250 port\n"); 134 clk_disable_unprepare(priv->sclk); 135 return ret; 136 } 137 138 priv->line = ret; 139 platform_set_drvdata(pdev, priv); 140 return 0; 141 } 142 143 static int serial8250_em_remove(struct platform_device *pdev) 144 { 145 struct serial8250_em_priv *priv = platform_get_drvdata(pdev); 146 147 serial8250_unregister_port(priv->line); 148 clk_disable_unprepare(priv->sclk); 149 return 0; 150 } 151 152 static const struct of_device_id serial8250_em_dt_ids[] = { 153 { .compatible = "renesas,em-uart", }, 154 {}, 155 }; 156 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); 157 158 static struct platform_driver serial8250_em_platform_driver = { 159 .driver = { 160 .name = "serial8250-em", 161 .of_match_table = serial8250_em_dt_ids, 162 }, 163 .probe = serial8250_em_probe, 164 .remove = serial8250_em_remove, 165 }; 166 167 module_platform_driver(serial8250_em_platform_driver); 168 169 MODULE_AUTHOR("Magnus Damm"); 170 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); 171 MODULE_LICENSE("GPL v2"); 172