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
34struct serial8250_em_priv {
35	struct clk *sclk;
36	int line;
37};
38
39static 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
60static 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
79static 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
84static 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
90static 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
142static 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
151static const struct of_device_id serial8250_em_dt_ids[] = {
152	{ .compatible = "renesas,em-uart", },
153	{},
154};
155MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);
156
157static 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
166module_platform_driver(serial8250_em_platform_driver);
167
168MODULE_AUTHOR("Magnus Damm");
169MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
170MODULE_LICENSE("GPL v2");
171