2 * Renesas Emma Mobile 8250 driver
4 * Copyright (C) 2012 Magnus Damm
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
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.
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
20 #include <linux/device.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>
33 #define UART_DLM_EM 10
35 struct serial8250_em_priv {
40 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
43 case UART_TX: /* TX @ 0x00 */
44 writeb(value, p->membase);
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));
52 case UART_IER: /* IER @ 0x04 */
53 value &= 0x0f; /* only 4 valid bits - not Xscale */
55 case UART_DLL_EM: /* DLL @ 0x24 (+9) */
56 case UART_DLM_EM: /* DLM @ 0x28 (+9) */
57 writel(value, p->membase + (offset << 2));
61 static unsigned int serial8250_em_serial_in(struct uart_port *p, int 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));
80 static int serial8250_em_serial_dl_read(struct uart_8250_port *up)
82 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
85 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value)
87 serial_out(up, UART_DLL_EM, value & 0xff);
88 serial_out(up, UART_DLM_EM, value >> 8 & 0xff);
91 static int serial8250_em_probe(struct platform_device *pdev)
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;
100 dev_err(&pdev->dev, "missing registers or irq\n");
104 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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);
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;
122 clk_prepare_enable(priv->sclk);
123 up.port.uartclk = clk_get_rate(priv->sclk);
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;
131 ret = serial8250_register_8250_port(&up);
133 dev_err(&pdev->dev, "unable to register 8250 port\n");
134 clk_disable_unprepare(priv->sclk);
139 platform_set_drvdata(pdev, priv);
143 static int serial8250_em_remove(struct platform_device *pdev)
145 struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
147 serial8250_unregister_port(priv->line);
148 clk_disable_unprepare(priv->sclk);
152 static const struct of_device_id serial8250_em_dt_ids[] = {
153 { .compatible = "renesas,em-uart", },
156 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);
158 static struct platform_driver serial8250_em_platform_driver = {
160 .name = "serial8250-em",
161 .of_match_table = serial8250_em_dt_ids,
163 .probe = serial8250_em_probe,
164 .remove = serial8250_em_remove,
167 module_platform_driver(serial8250_em_platform_driver);
169 MODULE_AUTHOR("Magnus Damm");
170 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
171 MODULE_LICENSE("GPL v2");