2 * Copyright (C) 2010 Lars-Peter Clausen <lars@metafoo.de>
3 * Copyright (C) 2015 Imagination Technologies
5 * Ingenic SoC UART support
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
12 * You should have received a copy of the GNU General Public License along
13 * with this program; if not, write to the Free Software Foundation, Inc.,
14 * 675 Mass Ave, Cambridge, MA 02139, USA.
17 #include <linux/clk.h>
18 #include <linux/console.h>
20 #include <linux/libfdt.h>
21 #include <linux/module.h>
23 #include <linux/of_fdt.h>
24 #include <linux/platform_device.h>
25 #include <linux/serial_8250.h>
26 #include <linux/serial_core.h>
27 #include <linux/serial_reg.h>
29 struct ingenic_uart_data {
30 struct clk *clk_module;
35 #define UART_FCR_UME BIT(4)
37 static struct earlycon_device *early_device;
39 static uint8_t __init early_in(struct uart_port *port, int offset)
41 return readl(port->membase + (offset << 2));
44 static void __init early_out(struct uart_port *port, int offset, uint8_t value)
46 writel(value, port->membase + (offset << 2));
49 static void __init ingenic_early_console_putc(struct uart_port *port, int c)
54 lsr = early_in(port, UART_LSR);
55 } while ((lsr & UART_LSR_TEMT) == 0);
57 early_out(port, UART_TX, c);
60 static void __init ingenic_early_console_write(struct console *console,
61 const char *s, unsigned int count)
63 uart_console_write(&early_device->port, s, count,
64 ingenic_early_console_putc);
67 static void __init ingenic_early_console_setup_clock(struct earlycon_device *dev)
69 void *fdt = initial_boot_params;
73 offset = fdt_path_offset(fdt, "/ext");
77 prop = fdt_getprop(fdt, offset, "clock-frequency", NULL);
81 dev->port.uartclk = be32_to_cpup(prop);
84 static int __init ingenic_early_console_setup(struct earlycon_device *dev,
87 struct uart_port *port = &dev->port;
88 unsigned int baud, divisor;
90 if (!dev->port.membase)
93 ingenic_early_console_setup_clock(dev);
95 baud = dev->baud ?: 115200;
96 divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
98 early_out(port, UART_IER, 0);
99 early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
100 early_out(port, UART_DLL, 0);
101 early_out(port, UART_DLM, 0);
102 early_out(port, UART_LCR, UART_LCR_WLEN8);
103 early_out(port, UART_FCR, UART_FCR_UME | UART_FCR_CLEAR_XMIT |
104 UART_FCR_CLEAR_RCVR | UART_FCR_ENABLE_FIFO);
105 early_out(port, UART_MCR, UART_MCR_RTS | UART_MCR_DTR);
107 early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
108 early_out(port, UART_DLL, divisor & 0xff);
109 early_out(port, UART_DLM, (divisor >> 8) & 0xff);
110 early_out(port, UART_LCR, UART_LCR_WLEN8);
113 dev->con->write = ingenic_early_console_write;
118 EARLYCON_DECLARE(jz4740_uart, ingenic_early_console_setup);
119 OF_EARLYCON_DECLARE(jz4740_uart, "ingenic,jz4740-uart",
120 ingenic_early_console_setup);
122 EARLYCON_DECLARE(jz4775_uart, ingenic_early_console_setup);
123 OF_EARLYCON_DECLARE(jz4775_uart, "ingenic,jz4775-uart",
124 ingenic_early_console_setup);
126 EARLYCON_DECLARE(jz4780_uart, ingenic_early_console_setup);
127 OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart",
128 ingenic_early_console_setup);
130 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
134 /* UART module enable */
135 value |= UART_FCR_UME;
139 value |= (value & 0x4) << 2;
146 writeb(value, p->membase + (offset << p->regshift));
149 static int ingenic_uart_probe(struct platform_device *pdev)
151 struct uart_8250_port uart = {};
152 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
153 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
154 struct ingenic_uart_data *data;
158 dev_err(&pdev->dev, "no registers/irq defined\n");
162 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
166 spin_lock_init(&uart.port.lock);
167 uart.port.type = PORT_16550;
168 uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
169 uart.port.iotype = UPIO_MEM;
170 uart.port.mapbase = regs->start;
171 uart.port.regshift = 2;
172 uart.port.serial_out = ingenic_uart_serial_out;
173 uart.port.irq = irq->start;
174 uart.port.dev = &pdev->dev;
176 /* Check for a fixed line number */
177 line = of_alias_get_id(pdev->dev.of_node, "serial");
179 uart.port.line = line;
181 uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
182 resource_size(regs));
183 if (!uart.port.membase)
186 data->clk_module = devm_clk_get(&pdev->dev, "module");
187 if (IS_ERR(data->clk_module)) {
188 err = PTR_ERR(data->clk_module);
189 if (err != -EPROBE_DEFER)
191 "unable to get module clock: %d\n", err);
195 data->clk_baud = devm_clk_get(&pdev->dev, "baud");
196 if (IS_ERR(data->clk_baud)) {
197 err = PTR_ERR(data->clk_baud);
198 if (err != -EPROBE_DEFER)
200 "unable to get baud clock: %d\n", err);
204 err = clk_prepare_enable(data->clk_module);
206 dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
210 err = clk_prepare_enable(data->clk_baud);
212 dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
213 goto out_disable_moduleclk;
215 uart.port.uartclk = clk_get_rate(data->clk_baud);
217 data->line = serial8250_register_8250_port(&uart);
218 if (data->line < 0) {
220 goto out_disable_baudclk;
223 platform_set_drvdata(pdev, data);
227 clk_disable_unprepare(data->clk_baud);
228 out_disable_moduleclk:
229 clk_disable_unprepare(data->clk_module);
234 static int ingenic_uart_remove(struct platform_device *pdev)
236 struct ingenic_uart_data *data = platform_get_drvdata(pdev);
238 serial8250_unregister_port(data->line);
239 clk_disable_unprepare(data->clk_module);
240 clk_disable_unprepare(data->clk_baud);
244 static const struct of_device_id of_match[] = {
245 { .compatible = "ingenic,jz4740-uart" },
246 { .compatible = "ingenic,jz4775-uart" },
247 { .compatible = "ingenic,jz4780-uart" },
250 MODULE_DEVICE_TABLE(of, of_match);
252 static struct platform_driver ingenic_uart_platform_driver = {
254 .name = "ingenic-uart",
255 .of_match_table = of_match,
257 .probe = ingenic_uart_probe,
258 .remove = ingenic_uart_remove,
261 module_platform_driver(ingenic_uart_platform_driver);
263 MODULE_AUTHOR("Paul Burton");
264 MODULE_LICENSE("GPL");
265 MODULE_DESCRIPTION("Ingenic SoC UART driver");