164 lines
4.0 KiB
C
164 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Renesas Emma Mobile 8250 driver
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*
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* Copyright (C) 2012 Magnus Damm
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*/
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/serial_8250.h>
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#include <linux/serial_reg.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/slab.h>
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#include "8250.h"
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#define UART_DLL_EM 9
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#define UART_DLM_EM 10
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struct serial8250_em_priv {
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struct clk *sclk;
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int line;
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};
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static void serial8250_em_serial_out(struct uart_port *p, int offset, int value)
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{
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switch (offset) {
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case UART_TX: /* TX @ 0x00 */
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writeb(value, p->membase);
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break;
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case UART_FCR: /* FCR @ 0x0c (+1) */
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case UART_LCR: /* LCR @ 0x10 (+1) */
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case UART_MCR: /* MCR @ 0x14 (+1) */
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case UART_SCR: /* SCR @ 0x20 (+1) */
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writel(value, p->membase + ((offset + 1) << 2));
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break;
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case UART_IER: /* IER @ 0x04 */
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value &= 0x0f; /* only 4 valid bits - not Xscale */
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fallthrough;
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case UART_DLL_EM: /* DLL @ 0x24 (+9) */
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case UART_DLM_EM: /* DLM @ 0x28 (+9) */
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writel(value, p->membase + (offset << 2));
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}
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}
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static unsigned int serial8250_em_serial_in(struct uart_port *p, int offset)
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{
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switch (offset) {
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case UART_RX: /* RX @ 0x00 */
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return readb(p->membase);
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case UART_MCR: /* MCR @ 0x14 (+1) */
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case UART_LSR: /* LSR @ 0x18 (+1) */
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case UART_MSR: /* MSR @ 0x1c (+1) */
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case UART_SCR: /* SCR @ 0x20 (+1) */
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return readl(p->membase + ((offset + 1) << 2));
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case UART_IER: /* IER @ 0x04 */
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case UART_IIR: /* IIR @ 0x08 */
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case UART_DLL_EM: /* DLL @ 0x24 (+9) */
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case UART_DLM_EM: /* DLM @ 0x28 (+9) */
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return readl(p->membase + (offset << 2));
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}
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return 0;
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}
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static int serial8250_em_serial_dl_read(struct uart_8250_port *up)
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{
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return serial_in(up, UART_DLL_EM) | serial_in(up, UART_DLM_EM) << 8;
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}
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static void serial8250_em_serial_dl_write(struct uart_8250_port *up, int value)
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{
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serial_out(up, UART_DLL_EM, value & 0xff);
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serial_out(up, UART_DLM_EM, value >> 8 & 0xff);
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}
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static int serial8250_em_probe(struct platform_device *pdev)
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{
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struct serial8250_em_priv *priv;
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struct uart_8250_port up;
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struct resource *regs;
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int irq, ret;
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irq = platform_get_irq(pdev, 0);
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if (irq < 0)
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return irq;
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regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!regs) {
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dev_err(&pdev->dev, "missing registers\n");
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return -EINVAL;
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}
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv->sclk = devm_clk_get(&pdev->dev, "sclk");
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if (IS_ERR(priv->sclk)) {
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dev_err(&pdev->dev, "unable to get clock\n");
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return PTR_ERR(priv->sclk);
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}
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memset(&up, 0, sizeof(up));
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up.port.mapbase = regs->start;
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up.port.irq = irq;
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up.port.type = PORT_16750;
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up.port.flags = UPF_FIXED_PORT | UPF_IOREMAP | UPF_FIXED_TYPE;
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up.port.dev = &pdev->dev;
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up.port.private_data = priv;
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clk_prepare_enable(priv->sclk);
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up.port.uartclk = clk_get_rate(priv->sclk);
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up.port.iotype = UPIO_MEM32;
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up.port.serial_in = serial8250_em_serial_in;
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up.port.serial_out = serial8250_em_serial_out;
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up.dl_read = serial8250_em_serial_dl_read;
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up.dl_write = serial8250_em_serial_dl_write;
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ret = serial8250_register_8250_port(&up);
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if (ret < 0) {
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dev_err(&pdev->dev, "unable to register 8250 port\n");
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clk_disable_unprepare(priv->sclk);
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return ret;
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}
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priv->line = ret;
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platform_set_drvdata(pdev, priv);
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return 0;
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}
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static int serial8250_em_remove(struct platform_device *pdev)
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{
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struct serial8250_em_priv *priv = platform_get_drvdata(pdev);
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serial8250_unregister_port(priv->line);
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clk_disable_unprepare(priv->sclk);
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return 0;
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}
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static const struct of_device_id serial8250_em_dt_ids[] = {
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{ .compatible = "renesas,em-uart", },
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{},
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};
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MODULE_DEVICE_TABLE(of, serial8250_em_dt_ids);
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static struct platform_driver serial8250_em_platform_driver = {
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.driver = {
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.name = "serial8250-em",
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.of_match_table = serial8250_em_dt_ids,
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},
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.probe = serial8250_em_probe,
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.remove = serial8250_em_remove,
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};
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module_platform_driver(serial8250_em_platform_driver);
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MODULE_AUTHOR("Magnus Damm");
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MODULE_DESCRIPTION("Renesas Emma Mobile 8250 Driver");
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MODULE_LICENSE("GPL v2");
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