202 lines
4.6 KiB
C
202 lines
4.6 KiB
C
/*
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* Simple CLPS711X serial driver
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*
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* (C) Copyright 2012-2014 Alexander Shiyan <shc_work@mail.ru>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <common.h>
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#include <malloc.h>
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#include <init.h>
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#include <io.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <mfd/syscon.h>
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#define UARTDR 0x00
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# define UARTDR_FRMERR (1 << 8)
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# define UARTDR_PARERR (1 << 9)
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# define UARTDR_OVERR (1 << 10)
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#define UBRLCR 0x40
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# define UBRLCR_BAUD_MASK ((1 << 12) - 1)
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# define UBRLCR_BREAK (1 << 12)
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# define UBRLCR_PRTEN (1 << 13)
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# define UBRLCR_EVENPRT (1 << 14)
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# define UBRLCR_XSTOP (1 << 15)
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# define UBRLCR_FIFOEN (1 << 16)
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# define UBRLCR_WRDLEN5 (0 << 17)
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# define UBRLCR_WRDLEN6 (1 << 17)
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# define UBRLCR_WRDLEN7 (2 << 17)
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# define UBRLCR_WRDLEN8 (3 << 17)
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# define UBRLCR_WRDLEN_MASK (3 << 17)
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#define SYSCON 0x00
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# define SYSCON_UARTEN (1 << 8)
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#define SYSFLG 0x40
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# define SYSFLG_UBUSY (1 << 11)
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# define SYSFLG_URXFE (1 << 22)
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# define SYSFLG_UTXFF (1 << 23)
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struct clps711x_uart {
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void __iomem *base;
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void __iomem *syscon;
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struct clk *uart_clk;
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struct console_device cdev;
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};
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static int clps711x_setbaudrate(struct console_device *cdev, int baudrate)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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int divisor;
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u32 tmp;
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divisor = (clk_get_rate(s->uart_clk) / 16) / baudrate;
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tmp = readl(s->base + UBRLCR) & ~UBRLCR_BAUD_MASK;
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tmp |= divisor - 1;
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writel(tmp, s->base + UBRLCR);
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return 0;
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}
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static void clps711x_init_port(struct console_device *cdev)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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u32 tmp;
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/* Disable the UART */
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tmp = readl(s->syscon + SYSCON);
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writel(tmp & ~SYSCON_UARTEN, s->syscon + SYSCON);
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/* Setup Line Control Register */
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tmp = readl(s->base + UBRLCR) & UBRLCR_BAUD_MASK;
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tmp |= UBRLCR_FIFOEN | UBRLCR_WRDLEN8; /* FIFO on, 8N1 mode */
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writel(tmp, s->base + UBRLCR);
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/* Enable the UART */
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tmp = readl(s->syscon + SYSCON);
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writel(tmp | SYSCON_UARTEN, s->syscon + SYSCON);
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}
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static void clps711x_putc(struct console_device *cdev, char c)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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/* Wait until there is space in the FIFO */
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do {
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} while (readl(s->syscon + SYSFLG) & SYSFLG_UTXFF);
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/* Send the character */
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writew(c, s->base + UARTDR);
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}
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static int clps711x_getc(struct console_device *cdev)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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u16 data;
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/* Wait until there is data in the FIFO */
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do {
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} while (readl(s->syscon + SYSFLG) & SYSFLG_URXFE);
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data = readw(s->base + UARTDR);
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/* Check for an error flag */
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if (data & (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR))
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return -1;
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return (int)data;
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}
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static int clps711x_tstc(struct console_device *cdev)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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return !(readl(s->syscon + SYSFLG) & SYSFLG_URXFE);
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}
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static void clps711x_flush(struct console_device *cdev)
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{
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struct clps711x_uart *s = cdev->dev->priv;
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do {
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} while (readl(s->syscon + SYSFLG) & SYSFLG_UBUSY);
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}
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static int clps711x_probe(struct device_d *dev)
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{
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struct clps711x_uart *s;
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int err, id = dev->id;
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char syscon_dev[8];
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if (dev->device_node)
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id = of_alias_get_id(dev->device_node, "serial");
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if (id != 0 && id != 1)
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return -EINVAL;
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s = xzalloc(sizeof(struct clps711x_uart));
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s->uart_clk = clk_get(dev, NULL);
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if (IS_ERR(s->uart_clk)) {
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err = PTR_ERR(s->uart_clk);
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goto out_err;
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}
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s->base = dev_get_mem_region(dev, 0);
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if (!dev->device_node) {
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sprintf(syscon_dev, "syscon%i", id + 1);
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s->syscon = syscon_base_lookup_by_pdevname(syscon_dev);
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} else {
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s->syscon = syscon_base_lookup_by_phandle(dev->device_node,
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"syscon");
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}
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if (IS_ERR(s->syscon)) {
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err = PTR_ERR(s->syscon);
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goto out_err;
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}
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dev->priv = s;
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s->cdev.dev = dev;
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s->cdev.tstc = clps711x_tstc;
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s->cdev.putc = clps711x_putc;
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s->cdev.getc = clps711x_getc;
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s->cdev.flush = clps711x_flush;
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s->cdev.setbrg = clps711x_setbaudrate;
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clps711x_init_port(&s->cdev);
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err = console_register(&s->cdev);
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out_err:
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if (err)
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free(s);
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return err;
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}
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static void clps711x_remove(struct device_d *dev)
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{
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struct clps711x_uart *s = dev->priv;
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clps711x_flush(&s->cdev);
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console_unregister(&s->cdev);
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free(s);
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}
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static struct of_device_id __maybe_unused clps711x_uart_dt_ids[] = {
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{ .compatible = "cirrus,clps711x-uart", },
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};
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static struct driver_d clps711x_driver = {
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.name = "clps711x-uart",
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.probe = clps711x_probe,
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.remove = clps711x_remove,
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.of_compatible = DRV_OF_COMPAT(clps711x_uart_dt_ids),
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};
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console_platform_driver(clps711x_driver);
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