8250_pxa.c

  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
 26#include "8250.h"
 27
 28struct pxa8250_data {
 29	int			line;
 30	struct clk		*clk;
 31};
 32
 33static int __maybe_unused serial_pxa_suspend(struct device *dev)
 34{
 35	struct pxa8250_data *data = dev_get_drvdata(dev);
 36
 37	serial8250_suspend_port(data->line);
 38
 39	return 0;
 40}
 41
 42static int __maybe_unused serial_pxa_resume(struct device *dev)
 43{
 44	struct pxa8250_data *data = dev_get_drvdata(dev);
 45
 46	serial8250_resume_port(data->line);
 47
 48	return 0;
 49}
 50
 51static const struct dev_pm_ops serial_pxa_pm_ops = {
 52	SET_SYSTEM_SLEEP_PM_OPS(serial_pxa_suspend, serial_pxa_resume)
 53};
 54
 55static const struct of_device_id serial_pxa_dt_ids[] = {
 56	{ .compatible = "mrvl,pxa-uart", },
 57	{ .compatible = "mrvl,mmp-uart", },
 58	{}
 59};
 60MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);
 61
 62/* Uart divisor latch write */
 63static void serial_pxa_dl_write(struct uart_8250_port *up, u32 value)
 64{
 65	unsigned int dll;
 66
 67	serial_out(up, UART_DLL, value & 0xff);
 68	/*
 69	 * work around Erratum #74 according to Marvel(R) PXA270M Processor
 70	 * Specification Update (April 19, 2010)
 71	 */
 72	dll = serial_in(up, UART_DLL);
 73	WARN_ON(dll != (value & 0xff));
 74
 75	serial_out(up, UART_DLM, value >> 8 & 0xff);
 76}
 77
 78
 79static void serial_pxa_pm(struct uart_port *port, unsigned int state,
 80	      unsigned int oldstate)
 81{
 82	struct pxa8250_data *data = port->private_data;
 83
 84	if (!state)
 85		clk_prepare_enable(data->clk);
 86	else
 87		clk_disable_unprepare(data->clk);
 88}
 89
 90static int serial_pxa_probe(struct platform_device *pdev)
 91{
 92	struct uart_8250_port uart = {};
 93	struct pxa8250_data *data;
 94	struct resource *mmres;
 95	int ret;
 96
 97	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 98	if (!mmres)
 99		return -ENODEV;
100
101	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
102	if (!data)
103		return -ENOMEM;
104
105	data->clk = devm_clk_get(&pdev->dev, NULL);
106	if (IS_ERR(data->clk))
107		return PTR_ERR(data->clk);
108
109	ret = clk_prepare(data->clk);
110	if (ret)
111		return ret;
112
113	uart.port.type = PORT_XSCALE;
114	uart.port.mapbase = mmres->start;
115	uart.port.flags = UPF_IOREMAP | UPF_SKIP_TEST | UPF_FIXED_TYPE;
116	uart.port.dev = &pdev->dev;
117	uart.port.uartclk = clk_get_rate(data->clk);
118	uart.port.pm = serial_pxa_pm;
119	uart.port.private_data = data;
120
121	ret = uart_read_port_properties(&uart.port);
122	if (ret)
123		return ret;
124
125	uart.port.iotype = UPIO_MEM32;
126	uart.port.regshift = 2;
127	uart.port.fifosize = 64;
128	uart.tx_loadsz = 32;
129	uart.dl_write = serial_pxa_dl_write;
130
131	ret = serial8250_register_8250_port(&uart);
132	if (ret < 0)
133		goto err_clk;
134
135	data->line = ret;
136
137	platform_set_drvdata(pdev, data);
138
139	return 0;
140
141 err_clk:
142	clk_unprepare(data->clk);
143	return ret;
144}
145
146static void serial_pxa_remove(struct platform_device *pdev)
147{
148	struct pxa8250_data *data = platform_get_drvdata(pdev);
149
150	serial8250_unregister_port(data->line);
151
152	clk_unprepare(data->clk);
153}
154
155static struct platform_driver serial_pxa_driver = {
156	.probe          = serial_pxa_probe,
157	.remove         = serial_pxa_remove,
158
159	.driver		= {
160		.name	= "pxa2xx-uart",
161		.pm	= &serial_pxa_pm_ops,
162		.of_match_table = serial_pxa_dt_ids,
163	},
164};
165
166module_platform_driver(serial_pxa_driver);
167
168MODULE_AUTHOR("Sergei Ianovich");
169MODULE_DESCRIPTION("driver for PXA on-board UARTS");
170MODULE_LICENSE("GPL");
171MODULE_ALIAS("platform:pxa2xx-uart");