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_reg.h> 25 #include <linux/platform_device.h> 26 #include <linux/clk.h> 27 #include <linux/slab.h> 28 29 #include "8250.h" 30 31 #define UART_DLL_EM 9 32 #define UART_DLM_EM 10 33 34 struct serial8250_em_priv { 35 struct clk *sclk; 36 int line; 37 }; 38 39 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) 40 { 41 switch (offset) { 42 case UART_TX: /* TX @ 0x00 */ 43 writeb(value, p->membase); 44 break; 45 case UART_FCR: /* FCR @ 0x0c (+1) */ 46 case UART_LCR: /* LCR @ 0x10 (+1) */ 47 case UART_MCR: /* MCR @ 0x14 (+1) */ 48 case UART_SCR: /* SCR @ 0x20 (+1) */ 49 writel(value, p->membase + ((offset + 1) << 2)); 50 break; 51 case UART_IER: /* IER @ 0x04 */ 52 value &= 0x0f; /* only 4 valid bits - not Xscale */ 53 /* fall-through */ 54 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 55 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 56 writel(value, p->membase + (offset << 2)); 57 } 58 } 59 60 static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) 61 { 62 switch (offset) { 63 case UART_RX: /* RX @ 0x00 */ 64 return readb(p->membase); 65 case UART_MCR: /* MCR @ 0x14 (+1) */ 66 case UART_LSR: /* LSR @ 0x18 (+1) */ 67 case UART_MSR: /* MSR @ 0x1c (+1) */ 68 case UART_SCR: /* SCR @ 0x20 (+1) */ 69 return readl(p->membase + ((offset + 1) << 2)); 70 case UART_IER: /* IER @ 0x04 */ 71 case UART_IIR: /* IIR @ 0x08 */ 72 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 73 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 74 return readl(p->membase + (offset << 2)); 75 } 76 return 0; 77 } 78 79 static int serial8250_em_serial_dl_read(struct uart_8250_port *up) 80 { 81 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; 82 } 83 84 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) 85 { 86 serial_out(up, UART_DLL_EM, value & 0xff); 87 serial_out(up, UART_DLM_EM, value >> 8 & 0xff); 88 } 89 90 static int serial8250_em_probe(struct platform_device *pdev) 91 { 92 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 93 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 94 struct serial8250_em_priv *priv; 95 struct uart_8250_port up; 96 int ret; 97 98 if (!regs || !irq) { 99 dev_err(&pdev->dev, "missing registers or irq\n"); 100 return -EINVAL; 101 } 102 103 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 104 if (!priv) 105 return -ENOMEM; 106 107 priv->sclk = devm_clk_get(&pdev->dev, "sclk"); 108 if (IS_ERR(priv->sclk)) { 109 dev_err(&pdev->dev, "unable to get clock\n"); 110 return PTR_ERR(priv->sclk); 111 } 112 113 memset(&up, 0, sizeof(up)); 114 up.port.mapbase = regs->start; 115 up.port.irq = irq->start; 116 up.port.type = PORT_UNKNOWN; 117 up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP; 118 up.port.dev = &pdev->dev; 119 up.port.private_data = priv; 120 121 clk_prepare_enable(priv->sclk); 122 up.port.uartclk = clk_get_rate(priv->sclk); 123 124 up.port.iotype = UPIO_MEM32; 125 up.port.serial_in = serial8250_em_serial_in; 126 up.port.serial_out = serial8250_em_serial_out; 127 up.dl_read = serial8250_em_serial_dl_read; 128 up.dl_write = serial8250_em_serial_dl_write; 129 130 ret = serial8250_register_8250_port(&up); 131 if (ret < 0) { 132 dev_err(&pdev->dev, "unable to register 8250 port\n"); 133 clk_disable_unprepare(priv->sclk); 134 return ret; 135 } 136 137 priv->line = ret; 138 platform_set_drvdata(pdev, priv); 139 return 0; 140 } 141 142 static int serial8250_em_remove(struct platform_device *pdev) 143 { 144 struct serial8250_em_priv *priv = platform_get_drvdata(pdev); 145 146 serial8250_unregister_port(priv->line); 147 clk_disable_unprepare(priv->sclk); 148 return 0; 149 } 150 151 static const struct of_device_id serial8250_em_dt_ids[] = { 152 { .compatible = "renesas,em-uart", }, 153 {}, 154 }; 155 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); 156 157 static struct platform_driver serial8250_em_platform_driver = { 158 .driver = { 159 .name = "serial8250-em", 160 .of_match_table = serial8250_em_dt_ids, 161 }, 162 .probe = serial8250_em_probe, 163 .remove = serial8250_em_remove, 164 }; 165 166 module_platform_driver(serial8250_em_platform_driver); 167 168 MODULE_AUTHOR("Magnus Damm"); 169 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); 170 MODULE_LICENSE("GPL v2"); 171