1 // SPDX-License-Identifier: GPL-2.0+
3 * Serial Port driver for Open Firmware platform devices
5 * Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
7 #include <linux/console.h>
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/serial_core.h>
11 #include <linux/serial_reg.h>
12 #include <linux/of_address.h>
13 #include <linux/of_irq.h>
14 #include <linux/of_platform.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/clk.h>
17 #include <linux/reset.h>
21 struct of_serial_info {
23 struct reset_control *rst;
29 * Fill a struct uart_port for a given device node
31 static int of_platform_serial_setup(struct platform_device *ofdev,
32 int type, struct uart_8250_port *up,
33 struct of_serial_info *info)
35 struct resource resource;
36 struct device_node *np = ofdev->dev.of_node;
37 struct uart_port *port = &up->port;
41 memset(port, 0, sizeof *port);
43 pm_runtime_enable(&ofdev->dev);
44 pm_runtime_get_sync(&ofdev->dev);
46 if (of_property_read_u32(np, "clock-frequency", &clk)) {
48 /* Get clk rate through clk driver if present */
49 info->clk = devm_clk_get(&ofdev->dev, NULL);
50 if (IS_ERR(info->clk)) {
51 ret = PTR_ERR(info->clk);
52 if (ret != -EPROBE_DEFER)
54 "failed to get clock: %d\n", ret);
58 ret = clk_prepare_enable(info->clk);
62 clk = clk_get_rate(info->clk);
64 /* If current-speed was set, then try not to change it. */
65 if (of_property_read_u32(np, "current-speed", &spd) == 0)
66 port->custom_divisor = clk / (16 * spd);
68 ret = of_address_to_resource(np, 0, &resource);
70 dev_warn(&ofdev->dev, "invalid address\n");
74 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
76 spin_lock_init(&port->lock);
78 if (resource_type(&resource) == IORESOURCE_IO) {
79 port->iotype = UPIO_PORT;
80 port->iobase = resource.start;
82 port->mapbase = resource.start;
83 port->mapsize = resource_size(&resource);
85 /* Check for shifted address mapping */
86 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
87 port->mapbase += prop;
89 port->iotype = UPIO_MEM;
90 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
93 port->iotype = UPIO_MEM;
96 port->iotype = UPIO_MEM16;
99 port->iotype = of_device_is_big_endian(np) ?
100 UPIO_MEM32BE : UPIO_MEM32;
103 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
109 port->flags |= UPF_IOREMAP;
112 /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
113 if (of_device_is_compatible(np, "mrvl,mmp-uart"))
116 /* Check for registers offset within the devices address range */
117 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
118 port->regshift = prop;
120 /* Check for fifo size */
121 if (of_property_read_u32(np, "fifo-size", &prop) == 0)
122 port->fifosize = prop;
124 /* Check for a fixed line number */
125 ret = of_alias_get_id(np, "serial");
129 irq = of_irq_get(np, 0);
131 if (irq == -EPROBE_DEFER) {
135 /* IRQ support not mandatory */
141 info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
142 if (IS_ERR(info->rst)) {
143 ret = PTR_ERR(info->rst);
147 ret = reset_control_deassert(info->rst);
154 if (of_property_read_bool(np, "no-loopback-test"))
155 port->flags |= UPF_SKIP_TEST;
157 port->dev = &ofdev->dev;
158 port->rs485_config = serial8250_em485_config;
159 up->rs485_start_tx = serial8250_em485_start_tx;
160 up->rs485_stop_tx = serial8250_em485_stop_tx;
164 port->iotype = UPIO_AU;
168 if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
169 (of_device_is_compatible(np, "fsl,ns16550") ||
170 of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
171 port->handle_irq = fsl8250_handle_irq;
172 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
177 clk_disable_unprepare(info->clk);
179 pm_runtime_put_sync(&ofdev->dev);
180 pm_runtime_disable(&ofdev->dev);
185 * Try to register a serial port
187 static int of_platform_serial_probe(struct platform_device *ofdev)
189 struct of_serial_info *info;
190 struct uart_8250_port port8250;
191 unsigned int port_type;
195 port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
196 if (port_type == PORT_UNKNOWN)
199 if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
202 info = kzalloc(sizeof(*info), GFP_KERNEL);
206 memset(&port8250, 0, sizeof(port8250));
207 ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
211 if (port8250.port.fifosize)
212 port8250.capabilities = UART_CAP_FIFO;
214 /* Check for TX FIFO threshold & set tx_loadsz */
215 if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
216 &tx_threshold) == 0) &&
217 (tx_threshold < port8250.port.fifosize))
218 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
220 if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
221 port8250.capabilities |= UART_CAP_AFE;
223 if (of_property_read_u32(ofdev->dev.of_node,
224 "overrun-throttle-ms",
225 &port8250.overrun_backoff_time_ms) != 0)
226 port8250.overrun_backoff_time_ms = 0;
228 ret = serial8250_register_8250_port(&port8250);
232 info->type = port_type;
234 platform_set_drvdata(ofdev, info);
237 irq_dispose_mapping(port8250.port.irq);
238 pm_runtime_put_sync(&ofdev->dev);
239 pm_runtime_disable(&ofdev->dev);
240 clk_disable_unprepare(info->clk);
249 static int of_platform_serial_remove(struct platform_device *ofdev)
251 struct of_serial_info *info = platform_get_drvdata(ofdev);
253 serial8250_unregister_port(info->line);
255 reset_control_assert(info->rst);
256 pm_runtime_put_sync(&ofdev->dev);
257 pm_runtime_disable(&ofdev->dev);
258 clk_disable_unprepare(info->clk);
263 #ifdef CONFIG_PM_SLEEP
264 static int of_serial_suspend(struct device *dev)
266 struct of_serial_info *info = dev_get_drvdata(dev);
267 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
268 struct uart_port *port = &port8250->port;
270 serial8250_suspend_port(info->line);
272 if (!uart_console(port) || console_suspend_enabled) {
273 pm_runtime_put_sync(dev);
274 clk_disable_unprepare(info->clk);
279 static int of_serial_resume(struct device *dev)
281 struct of_serial_info *info = dev_get_drvdata(dev);
282 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
283 struct uart_port *port = &port8250->port;
285 if (!uart_console(port) || console_suspend_enabled) {
286 pm_runtime_get_sync(dev);
287 clk_prepare_enable(info->clk);
290 serial8250_resume_port(info->line);
295 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
298 * A few common types, add more as needed.
300 static const struct of_device_id of_platform_serial_table[] = {
301 { .compatible = "ns8250", .data = (void *)PORT_8250, },
302 { .compatible = "ns16450", .data = (void *)PORT_16450, },
303 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
304 { .compatible = "ns16550", .data = (void *)PORT_16550, },
305 { .compatible = "ns16750", .data = (void *)PORT_16750, },
306 { .compatible = "ns16850", .data = (void *)PORT_16850, },
307 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
308 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
309 { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
310 { .compatible = "altr,16550-FIFO32",
311 .data = (void *)PORT_ALTR_16550_F32, },
312 { .compatible = "altr,16550-FIFO64",
313 .data = (void *)PORT_ALTR_16550_F64, },
314 { .compatible = "altr,16550-FIFO128",
315 .data = (void *)PORT_ALTR_16550_F128, },
316 { .compatible = "mediatek,mtk-btif",
317 .data = (void *)PORT_MTK_BTIF, },
318 { .compatible = "mrvl,mmp-uart",
319 .data = (void *)PORT_XSCALE, },
320 { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
321 { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, },
322 { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
323 { /* end of list */ },
325 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
327 static struct platform_driver of_platform_serial_driver = {
330 .of_match_table = of_platform_serial_table,
331 .pm = &of_serial_pm_ops,
333 .probe = of_platform_serial_probe,
334 .remove = of_platform_serial_remove,
337 module_platform_driver(of_platform_serial_driver);
339 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
340 MODULE_LICENSE("GPL");
341 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");