1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  drivers/tty/serial/8250/8250_pxa.c -- driver for PXA on-board UARTS
4  *  Copyright:	(C) 2013 Sergei Ianovich <ynvich@gmail.com>
5  *
6  *  replaces drivers/serial/pxa.c by Nicolas Pitre
7  *  Created:	Feb 20, 2003
8  *  Copyright:	(C) 2003 Monta Vista Software, Inc.
9  *
10  *  Based on drivers/serial/8250.c by Russell King.
11  */
12 
13 #include <linux/device.h>
14 #include <linux/init.h>
15 #include <linux/io.h>
16 #include <linux/module.h>
17 #include <linux/serial_8250.h>
18 #include <linux/serial_core.h>
19 #include <linux/serial_reg.h>
20 #include <linux/of.h>
21 #include <linux/of_platform.h>
22 #include <linux/platform_device.h>
23 #include <linux/slab.h>
24 #include <linux/clk.h>
25 #include <linux/pm_runtime.h>
26 
27 #include "8250.h"
28 
29 struct pxa8250_data {
30 	int			line;
31 	struct clk		*clk;
32 };
33 
serial_pxa_suspend(struct device * dev)34 static int __maybe_unused serial_pxa_suspend(struct device *dev)
35 {
36 	struct pxa8250_data *data = dev_get_drvdata(dev);
37 
38 	serial8250_suspend_port(data->line);
39 
40 	return 0;
41 }
42 
serial_pxa_resume(struct device * dev)43 static int __maybe_unused serial_pxa_resume(struct device *dev)
44 {
45 	struct pxa8250_data *data = dev_get_drvdata(dev);
46 
47 	serial8250_resume_port(data->line);
48 
49 	return 0;
50 }
51 
52 static const struct dev_pm_ops serial_pxa_pm_ops = {
53 	SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
54 };
55 
56 static const struct of_device_id serial_pxa_dt_ids[] = {
57 	{ .compatible = "mrvl,pxa-uart", },
58 	{ .compatible = "mrvl,mmp-uart", },
59 	{}
60 };
61 MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
62 
63 /* Uart divisor latch write */
serial_pxa_dl_write(struct uart_8250_port * up,int value)64 static void serial_pxa_dl_write(struct uart_8250_port *up, int value)
65 {
66 	unsigned int dll;
67 
68 	serial_out(up, UART_DLL, value & 0xff);
69 	/*
70 	 * work around Erratum #74 according to Marvel(R) PXA270M Processor
71 	 * Specification Update (April 19, 2010)
72 	 */
73 	dll = serial_in(up, UART_DLL);
74 	WARN_ON(dll != (value & 0xff));
75 
76 	serial_out(up, UART_DLM, value >> 8 & 0xff);
77 }
78 
79 
serial_pxa_pm(struct uart_port * port,unsigned int state,unsigned int oldstate)80 static void serial_pxa_pm(struct uart_port *port, unsigned int state,
81 	      unsigned int oldstate)
82 {
83 	struct pxa8250_data *data = port->private_data;
84 
85 	if (!state)
86 		clk_prepare_enable(data->clk);
87 	else
88 		clk_disable_unprepare(data->clk);
89 }
90 
serial_pxa_probe(struct platform_device * pdev)91 static int serial_pxa_probe(struct platform_device *pdev)
92 {
93 	struct uart_8250_port uart = {};
94 	struct pxa8250_data *data;
95 	struct resource *mmres;
96 	int irq, ret;
97 
98 	irq = platform_get_irq(pdev, 0);
99 	if (irq < 0)
100 		return irq;
101 
102 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
103 	if (!mmres)
104 		return -ENODEV;
105 
106 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
107 	if (!data)
108 		return -ENOMEM;
109 
110 	data->clk = devm_clk_get(&pdev->dev, NULL);
111 	if (IS_ERR(data->clk))
112 		return PTR_ERR(data->clk);
113 
114 	ret = clk_prepare(data->clk);
115 	if (ret)
116 		return ret;
117 
118 	ret = of_alias_get_id(pdev->dev.of_node, "serial");
119 	if (ret >= 0)
120 		uart.port.line = ret;
121 
122 	uart.port.type = PORT_XSCALE;
123 	uart.port.iotype = UPIO_MEM32;
124 	uart.port.mapbase = mmres->start;
125 	uart.port.regshift = 2;
126 	uart.port.irq = irq;
127 	uart.port.fifosize = 64;
128 	uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
129 	uart.port.dev = &pdev->dev;
130 	uart.port.uartclk = clk_get_rate(data->clk);
131 	uart.port.pm = serial_pxa_pm;
132 	uart.port.private_data = data;
133 	uart.dl_write = serial_pxa_dl_write;
134 
135 	ret = serial8250_register_8250_port(&uart);
136 	if (ret < 0)
137 		goto err_clk;
138 
139 	data->line = ret;
140 
141 	platform_set_drvdata(pdev, data);
142 
143 	return 0;
144 
145  err_clk:
146 	clk_unprepare(data->clk);
147 	return ret;
148 }
149 
serial_pxa_remove(struct platform_device * pdev)150 static int serial_pxa_remove(struct platform_device *pdev)
151 {
152 	struct pxa8250_data *data = platform_get_drvdata(pdev);
153 
154 	serial8250_unregister_port(data->line);
155 
156 	clk_unprepare(data->clk);
157 
158 	return 0;
159 }
160 
161 static struct platform_driver serial_pxa_driver = {
162 	.probe          = serial_pxa_probe,
163 	.remove         = serial_pxa_remove,
164 
165 	.driver		= {
166 		.name	= "pxa2xx-uart",
167 		.pm	= &serial_pxa_pm_ops,
168 		.of_match_table = serial_pxa_dt_ids,
169 	},
170 };
171 
172 module_platform_driver(serial_pxa_driver);
173 
174 #ifdef CONFIG_SERIAL_8250_CONSOLE
early_serial_pxa_setup(struct earlycon_device * device,const char * options)175 static int __init early_serial_pxa_setup(struct earlycon_device *device,
176 				  const char *options)
177 {
178 	struct uart_port *port = &device->port;
179 
180 	if (!(device->port.membase || device->port.iobase))
181 		return -ENODEV;
182 
183 	port->regshift = 2;
184 	return early_serial8250_setup(device, NULL);
185 }
186 OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup);
187 #endif
188 
189 MODULE_AUTHOR("Sergei Ianovich");
190 MODULE_LICENSE("GPL");
191 MODULE_ALIAS("platform:pxa2xx-uart");
192