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/init.h> 22 #include <linux/io.h> 23 #include <linux/module.h> 24 #include <linux/serial_8250.h> 25 #include <linux/serial_core.h> 26 #include <linux/serial_reg.h> 27 #include <linux/platform_device.h> 28 #include <linux/clk.h> 29 #include <linux/slab.h> 30 31 #include "8250.h" 32 33 #define UART_DLL_EM 9 34 #define UART_DLM_EM 10 35 36 struct serial8250_em_priv { 37 struct clk *sclk; 38 int line; 39 }; 40 41 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value) 42 { 43 switch (offset) { 44 case UART_TX: /* TX @ 0x00 */ 45 writeb(value, p->membase); 46 break; 47 case UART_FCR: /* FCR @ 0x0c (+1) */ 48 case UART_LCR: /* LCR @ 0x10 (+1) */ 49 case UART_MCR: /* MCR @ 0x14 (+1) */ 50 case UART_SCR: /* SCR @ 0x20 (+1) */ 51 writel(value, p->membase + ((offset + 1) << 2)); 52 break; 53 case UART_IER: /* IER @ 0x04 */ 54 value &= 0x0f; /* only 4 valid bits - not Xscale */ 55 /* fall-through */ 56 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 57 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 58 writel(value, p->membase + (offset << 2)); 59 } 60 } 61 62 static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset) 63 { 64 switch (offset) { 65 case UART_RX: /* RX @ 0x00 */ 66 return readb(p->membase); 67 case UART_MCR: /* MCR @ 0x14 (+1) */ 68 case UART_LSR: /* LSR @ 0x18 (+1) */ 69 case UART_MSR: /* MSR @ 0x1c (+1) */ 70 case UART_SCR: /* SCR @ 0x20 (+1) */ 71 return readl(p->membase + ((offset + 1) << 2)); 72 case UART_IER: /* IER @ 0x04 */ 73 case UART_IIR: /* IIR @ 0x08 */ 74 case UART_DLL_EM: /* DLL @ 0x24 (+9) */ 75 case UART_DLM_EM: /* DLM @ 0x28 (+9) */ 76 return readl(p->membase + (offset << 2)); 77 } 78 return 0; 79 } 80 81 static int serial8250_em_serial_dl_read(struct uart_8250_port *up) 82 { 83 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8; 84 } 85 86 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value) 87 { 88 serial_out(up, UART_DLL_EM, value & 0xff); 89 serial_out(up, UART_DLM_EM, value >> 8 & 0xff); 90 } 91 92 static int serial8250_em_probe(struct platform_device *pdev) 93 { 94 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 95 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 96 struct serial8250_em_priv *priv; 97 struct uart_8250_port up; 98 int ret; 99 100 if (!regs || !irq) { 101 dev_err(&pdev->dev, "missing registers or irq\n"); 102 return -EINVAL; 103 } 104 105 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 106 if (!priv) { 107 dev_err(&pdev->dev, "unable to allocate private data\n"); 108 return -ENOMEM; 109 } 110 111 priv->sclk = devm_clk_get(&pdev->dev, "sclk"); 112 if (IS_ERR(priv->sclk)) { 113 dev_err(&pdev->dev, "unable to get clock\n"); 114 return PTR_ERR(priv->sclk); 115 } 116 117 memset(&up, 0, sizeof(up)); 118 up.port.mapbase = regs->start; 119 up.port.irq = irq->start; 120 up.port.type = PORT_UNKNOWN; 121 up.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_IOREMAP; 122 up.port.dev = &pdev->dev; 123 up.port.private_data = priv; 124 125 clk_prepare_enable(priv->sclk); 126 up.port.uartclk = clk_get_rate(priv->sclk); 127 128 up.port.iotype = UPIO_MEM32; 129 up.port.serial_in = serial8250_em_serial_in; 130 up.port.serial_out = serial8250_em_serial_out; 131 up.dl_read = serial8250_em_serial_dl_read; 132 up.dl_write = serial8250_em_serial_dl_write; 133 134 ret = serial8250_register_8250_port(&up); 135 if (ret < 0) { 136 dev_err(&pdev->dev, "unable to register 8250 port\n"); 137 clk_disable_unprepare(priv->sclk); 138 return ret; 139 } 140 141 priv->line = ret; 142 platform_set_drvdata(pdev, priv); 143 return 0; 144 } 145 146 static int serial8250_em_remove(struct platform_device *pdev) 147 { 148 struct serial8250_em_priv *priv = platform_get_drvdata(pdev); 149 150 serial8250_unregister_port(priv->line); 151 clk_disable_unprepare(priv->sclk); 152 return 0; 153 } 154 155 static const struct of_device_id serial8250_em_dt_ids[] = { 156 { .compatible = "renesas,em-uart", }, 157 {}, 158 }; 159 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids); 160 161 static struct platform_driver serial8250_em_platform_driver = { 162 .driver = { 163 .name = "serial8250-em", 164 .of_match_table = serial8250_em_dt_ids, 165 .owner = THIS_MODULE, 166 }, 167 .probe = serial8250_em_probe, 168 .remove = serial8250_em_remove, 169 }; 170 171 module_platform_driver(serial8250_em_platform_driver); 172 173 MODULE_AUTHOR("Magnus Damm"); 174 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver"); 175 MODULE_LICENSE("GPL v2"); 176