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 if (prop >= port->mapsize) {
88 dev_warn(&ofdev->dev, "reg-offset %u exceeds region size %pa\n",
89 prop, &port->mapsize);
94 port->mapbase += prop;
95 port->mapsize -= prop;
98 port->iotype = UPIO_MEM;
99 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
102 port->iotype = UPIO_MEM;
105 port->iotype = UPIO_MEM16;
108 port->iotype = of_device_is_big_endian(np) ?
109 UPIO_MEM32BE : UPIO_MEM32;
112 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
118 port->flags |= UPF_IOREMAP;
121 /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
122 if (of_device_is_compatible(np, "mrvl,mmp-uart"))
125 /* Check for registers offset within the devices address range */
126 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
127 port->regshift = prop;
129 /* Check for fifo size */
130 if (of_property_read_u32(np, "fifo-size", &prop) == 0)
131 port->fifosize = prop;
133 /* Check for a fixed line number */
134 ret = of_alias_get_id(np, "serial");
138 irq = of_irq_get(np, 0);
140 if (irq == -EPROBE_DEFER) {
144 /* IRQ support not mandatory */
150 info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
151 if (IS_ERR(info->rst)) {
152 ret = PTR_ERR(info->rst);
156 ret = reset_control_deassert(info->rst);
163 if (of_property_read_bool(np, "no-loopback-test"))
164 port->flags |= UPF_SKIP_TEST;
166 port->dev = &ofdev->dev;
167 port->rs485_config = serial8250_em485_config;
168 up->rs485_start_tx = serial8250_em485_start_tx;
169 up->rs485_stop_tx = serial8250_em485_stop_tx;
173 port->iotype = UPIO_AU;
177 if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
178 (of_device_is_compatible(np, "fsl,ns16550") ||
179 of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
180 port->handle_irq = fsl8250_handle_irq;
181 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
186 clk_disable_unprepare(info->clk);
188 pm_runtime_put_sync(&ofdev->dev);
189 pm_runtime_disable(&ofdev->dev);
194 * Try to register a serial port
196 static int of_platform_serial_probe(struct platform_device *ofdev)
198 struct of_serial_info *info;
199 struct uart_8250_port port8250;
200 unsigned int port_type;
204 if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) &&
205 of_device_is_compatible(ofdev->dev.of_node, "brcm,bcm7271-uart"))
208 port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
209 if (port_type == PORT_UNKNOWN)
212 if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
215 info = kzalloc(sizeof(*info), GFP_KERNEL);
219 memset(&port8250, 0, sizeof(port8250));
220 ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
224 if (port8250.port.fifosize)
225 port8250.capabilities = UART_CAP_FIFO;
227 /* Check for TX FIFO threshold & set tx_loadsz */
228 if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
229 &tx_threshold) == 0) &&
230 (tx_threshold < port8250.port.fifosize))
231 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
233 if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
234 port8250.capabilities |= UART_CAP_AFE;
236 if (of_property_read_u32(ofdev->dev.of_node,
237 "overrun-throttle-ms",
238 &port8250.overrun_backoff_time_ms) != 0)
239 port8250.overrun_backoff_time_ms = 0;
241 ret = serial8250_register_8250_port(&port8250);
245 info->type = port_type;
247 platform_set_drvdata(ofdev, info);
250 irq_dispose_mapping(port8250.port.irq);
251 pm_runtime_put_sync(&ofdev->dev);
252 pm_runtime_disable(&ofdev->dev);
253 clk_disable_unprepare(info->clk);
262 static int of_platform_serial_remove(struct platform_device *ofdev)
264 struct of_serial_info *info = platform_get_drvdata(ofdev);
266 serial8250_unregister_port(info->line);
268 reset_control_assert(info->rst);
269 pm_runtime_put_sync(&ofdev->dev);
270 pm_runtime_disable(&ofdev->dev);
271 clk_disable_unprepare(info->clk);
276 #ifdef CONFIG_PM_SLEEP
277 static int of_serial_suspend(struct device *dev)
279 struct of_serial_info *info = dev_get_drvdata(dev);
280 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
281 struct uart_port *port = &port8250->port;
283 serial8250_suspend_port(info->line);
285 if (!uart_console(port) || console_suspend_enabled) {
286 pm_runtime_put_sync(dev);
287 clk_disable_unprepare(info->clk);
292 static int of_serial_resume(struct device *dev)
294 struct of_serial_info *info = dev_get_drvdata(dev);
295 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
296 struct uart_port *port = &port8250->port;
298 if (!uart_console(port) || console_suspend_enabled) {
299 pm_runtime_get_sync(dev);
300 clk_prepare_enable(info->clk);
303 serial8250_resume_port(info->line);
308 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
311 * A few common types, add more as needed.
313 static const struct of_device_id of_platform_serial_table[] = {
314 { .compatible = "ns8250", .data = (void *)PORT_8250, },
315 { .compatible = "ns16450", .data = (void *)PORT_16450, },
316 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
317 { .compatible = "ns16550", .data = (void *)PORT_16550, },
318 { .compatible = "ns16750", .data = (void *)PORT_16750, },
319 { .compatible = "ns16850", .data = (void *)PORT_16850, },
320 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
321 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
322 { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
323 { .compatible = "altr,16550-FIFO32",
324 .data = (void *)PORT_ALTR_16550_F32, },
325 { .compatible = "altr,16550-FIFO64",
326 .data = (void *)PORT_ALTR_16550_F64, },
327 { .compatible = "altr,16550-FIFO128",
328 .data = (void *)PORT_ALTR_16550_F128, },
329 { .compatible = "mediatek,mtk-btif",
330 .data = (void *)PORT_MTK_BTIF, },
331 { .compatible = "mrvl,mmp-uart",
332 .data = (void *)PORT_XSCALE, },
333 { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
334 { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, },
335 { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
336 { /* end of list */ },
338 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
340 static struct platform_driver of_platform_serial_driver = {
343 .of_match_table = of_platform_serial_table,
344 .pm = &of_serial_pm_ops,
346 .probe = of_platform_serial_probe,
347 .remove = of_platform_serial_remove,
350 module_platform_driver(of_platform_serial_driver);
352 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
353 MODULE_LICENSE("GPL");
354 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");