1 // SPDX-License-Identifier: GPL-2.0
3 * Renesas Emma Mobile 8250 driver
5 * Copyright (C) 2012 Magnus Damm
8 #include <linux/device.h>
10 #include <linux/module.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/serial_8250.h>
13 #include <linux/serial_reg.h>
14 #include <linux/platform_device.h>
15 #include <linux/clk.h>
20 #define UART_DLM_EM 10
21 #define UART_HCR0_EM 11
24 * A high value for UART_FCR_EM avoids overlapping with existing UART_*
25 * register defines. UART_FCR_EM_HW is the real HW register offset.
27 #define UART_FCR_EM 0x10003
28 #define UART_FCR_EM_HW 3
30 #define UART_HCR0_EM_SW_RESET BIT(7) /* SW Reset */
32 struct serial8250_em_priv {
36 static void serial8250_em_serial_out_helper(struct uart_port *p, int offset,
40 case UART_TX: /* TX @ 0x00 */
41 writeb(value, p->membase);
43 case UART_LCR: /* LCR @ 0x10 (+1) */
44 case UART_MCR: /* MCR @ 0x14 (+1) */
45 case UART_SCR: /* SCR @ 0x20 (+1) */
46 writel(value, p->membase + ((offset + 1) << 2));
49 writel(value, p->membase + (UART_FCR_EM_HW << 2));
51 case UART_IER: /* IER @ 0x04 */
52 value &= 0x0f; /* only 4 valid bits - not Xscale */
54 case UART_DLL_EM: /* DLL @ 0x24 (+9) */
55 case UART_DLM_EM: /* DLM @ 0x28 (+9) */
56 case UART_HCR0_EM: /* HCR0 @ 0x2c */
57 writel(value, p->membase + (offset << 2));
62 static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
65 case UART_RX: /* RX @ 0x00 */
66 return readb(p->membase);
67 case UART_LCR: /* LCR @ 0x10 (+1) */
68 case UART_MCR: /* MCR @ 0x14 (+1) */
69 case UART_LSR: /* LSR @ 0x18 (+1) */
70 case UART_MSR: /* MSR @ 0x1c (+1) */
71 case UART_SCR: /* SCR @ 0x20 (+1) */
72 return readl(p->membase + ((offset + 1) << 2));
74 return readl(p->membase + (UART_FCR_EM_HW << 2));
75 case UART_IER: /* IER @ 0x04 */
76 case UART_IIR: /* IIR @ 0x08 */
77 case UART_DLL_EM: /* DLL @ 0x24 (+9) */
78 case UART_DLM_EM: /* DLM @ 0x28 (+9) */
79 case UART_HCR0_EM: /* HCR0 @ 0x2c */
80 return readl(p->membase + (offset << 2));
85 static void serial8250_em_reg_update(struct uart_port *p, int off, int value)
87 unsigned int ier, fcr, lcr, mcr, hcr0;
89 ier = serial8250_em_serial_in(p, UART_IER);
90 fcr = serial8250_em_serial_in(p, UART_FCR_EM);
91 lcr = serial8250_em_serial_in(p, UART_LCR);
92 mcr = serial8250_em_serial_in(p, UART_MCR);
93 hcr0 = serial8250_em_serial_in(p, UART_HCR0_EM);
95 serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr |
98 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 |
99 UART_HCR0_EM_SW_RESET);
100 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0 &
101 ~UART_HCR0_EM_SW_RESET);
115 serial8250_em_serial_out_helper(p, UART_IER, ier);
116 serial8250_em_serial_out_helper(p, UART_FCR_EM, fcr);
117 serial8250_em_serial_out_helper(p, UART_MCR, mcr);
118 serial8250_em_serial_out_helper(p, UART_LCR, lcr);
119 serial8250_em_serial_out_helper(p, UART_HCR0_EM, hcr0);
122 static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
130 serial8250_em_serial_out_helper(p, offset, value);
133 serial8250_em_reg_update(p, UART_FCR_EM, value);
137 serial8250_em_reg_update(p, offset, value);
142 static u32 serial8250_em_serial_dl_read(struct uart_8250_port *up)
144 return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
147 static void serial8250_em_serial_dl_write(struct uart_8250_port *up, u32 value)
149 serial_out(up, UART_DLL_EM, value & 0xff);
150 serial_out(up, UART_DLM_EM, value >> 8 & 0xff);
153 static int serial8250_em_probe(struct platform_device *pdev)
155 struct serial8250_em_priv *priv;
156 struct device *dev = &pdev->dev;
157 struct uart_8250_port up;
158 struct resource *regs;
162 irq = platform_get_irq(pdev, 0);
166 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
168 return dev_err_probe(dev, -EINVAL, "missing registers\n");
170 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
174 sclk = devm_clk_get_enabled(dev, "sclk");
176 return dev_err_probe(dev, PTR_ERR(sclk), "unable to get clock\n");
178 memset(&up, 0, sizeof(up));
179 up.port.mapbase = regs->start;
181 up.port.type = PORT_16750;
182 up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE;
184 up.port.private_data = priv;
186 up.port.uartclk = clk_get_rate(sclk);
188 up.port.iotype = UPIO_MEM32;
189 up.port.serial_in = serial8250_em_serial_in;
190 up.port.serial_out = serial8250_em_serial_out;
191 up.dl_read = serial8250_em_serial_dl_read;
192 up.dl_write = serial8250_em_serial_dl_write;
194 ret = serial8250_register_8250_port(&up);
196 return dev_err_probe(dev, ret, "unable to register 8250 port\n");
199 platform_set_drvdata(pdev, priv);
203 static void serial8250_em_remove(struct platform_device *pdev)
205 struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
207 serial8250_unregister_port(priv->line);
210 static const struct of_device_id serial8250_em_dt_ids[] = {
211 { .compatible = "renesas,em-uart", },
214 MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);
216 static struct platform_driver serial8250_em_platform_driver = {
218 .name = "serial8250-em",
219 .of_match_table = serial8250_em_dt_ids,
221 .probe = serial8250_em_probe,
222 .remove_new = serial8250_em_remove,
225 module_platform_driver(serial8250_em_platform_driver);
227 MODULE_AUTHOR("Magnus Damm");
228 MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
229 MODULE_LICENSE("GPL v2");