mirror of https://gitee.com/openkylin/linux.git
562 lines
14 KiB
C
562 lines
14 KiB
C
/*
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* Driver for Conexant Digicolor serial ports (USART)
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*
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* Author: Baruch Siach <baruch@tkos.co.il>
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*
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* Copyright (C) 2014 Paradox Innovation Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/console.h>
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#include <linux/serial_core.h>
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#include <linux/serial.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/workqueue.h>
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#define UA_ENABLE 0x00
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#define UA_ENABLE_ENABLE BIT(0)
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#define UA_CONTROL 0x01
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#define UA_CONTROL_RX_ENABLE BIT(0)
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#define UA_CONTROL_TX_ENABLE BIT(1)
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#define UA_CONTROL_SOFT_RESET BIT(2)
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#define UA_STATUS 0x02
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#define UA_STATUS_PARITY_ERR BIT(0)
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#define UA_STATUS_FRAME_ERR BIT(1)
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#define UA_STATUS_OVERRUN_ERR BIT(2)
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#define UA_STATUS_TX_READY BIT(6)
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#define UA_CONFIG 0x03
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#define UA_CONFIG_CHAR_LEN BIT(0)
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#define UA_CONFIG_STOP_BITS BIT(1)
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#define UA_CONFIG_PARITY BIT(2)
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#define UA_CONFIG_ODD_PARITY BIT(4)
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#define UA_EMI_REC 0x04
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#define UA_HBAUD_LO 0x08
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#define UA_HBAUD_HI 0x09
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#define UA_STATUS_FIFO 0x0a
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#define UA_STATUS_FIFO_RX_EMPTY BIT(2)
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#define UA_STATUS_FIFO_RX_INT_ALMOST BIT(3)
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#define UA_STATUS_FIFO_TX_FULL BIT(4)
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#define UA_STATUS_FIFO_TX_INT_ALMOST BIT(7)
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#define UA_CONFIG_FIFO 0x0b
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#define UA_CONFIG_FIFO_RX_THRESH 7
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#define UA_CONFIG_FIFO_RX_FIFO_MODE BIT(3)
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#define UA_CONFIG_FIFO_TX_FIFO_MODE BIT(7)
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#define UA_INTFLAG_CLEAR 0x1c
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#define UA_INTFLAG_SET 0x1d
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#define UA_INT_ENABLE 0x1e
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#define UA_INT_STATUS 0x1f
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#define UA_INT_TX BIT(0)
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#define UA_INT_RX BIT(1)
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#define DIGICOLOR_USART_NR 3
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/*
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* We use the 16 bytes hardware FIFO to buffer Rx traffic. Rx interrupt is
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* only produced when the FIFO is filled more than a certain configurable
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* threshold. Unfortunately, there is no way to set this threshold below half
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* FIFO. This means that we must periodically poll the FIFO status register to
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* see whether there are waiting Rx bytes.
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*/
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struct digicolor_port {
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struct uart_port port;
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struct delayed_work rx_poll_work;
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};
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static struct uart_port *digicolor_ports[DIGICOLOR_USART_NR];
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static bool digicolor_uart_tx_full(struct uart_port *port)
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{
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return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
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UA_STATUS_FIFO_TX_FULL);
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}
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static bool digicolor_uart_rx_empty(struct uart_port *port)
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{
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return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
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UA_STATUS_FIFO_RX_EMPTY);
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}
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static void digicolor_uart_stop_tx(struct uart_port *port)
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{
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u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
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int_enable &= ~UA_INT_TX;
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writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
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}
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static void digicolor_uart_start_tx(struct uart_port *port)
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{
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u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
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int_enable |= UA_INT_TX;
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writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
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}
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static void digicolor_uart_stop_rx(struct uart_port *port)
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{
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u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
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int_enable &= ~UA_INT_RX;
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writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
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}
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static void digicolor_rx_poll(struct work_struct *work)
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{
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struct digicolor_port *dp =
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container_of(to_delayed_work(work),
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struct digicolor_port, rx_poll_work);
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if (!digicolor_uart_rx_empty(&dp->port))
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/* force RX interrupt */
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writeb_relaxed(UA_INT_RX, dp->port.membase + UA_INTFLAG_SET);
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schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
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}
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static void digicolor_uart_rx(struct uart_port *port)
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{
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unsigned long flags;
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spin_lock_irqsave(&port->lock, flags);
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while (1) {
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u8 status, ch;
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unsigned int ch_flag;
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if (digicolor_uart_rx_empty(port))
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break;
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ch = readb_relaxed(port->membase + UA_EMI_REC);
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status = readb_relaxed(port->membase + UA_STATUS);
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port->icount.rx++;
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ch_flag = TTY_NORMAL;
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if (status) {
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if (status & UA_STATUS_PARITY_ERR)
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port->icount.parity++;
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else if (status & UA_STATUS_FRAME_ERR)
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port->icount.frame++;
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else if (status & UA_STATUS_OVERRUN_ERR)
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port->icount.overrun++;
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status &= port->read_status_mask;
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if (status & UA_STATUS_PARITY_ERR)
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ch_flag = TTY_PARITY;
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else if (status & UA_STATUS_FRAME_ERR)
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ch_flag = TTY_FRAME;
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else if (status & UA_STATUS_OVERRUN_ERR)
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ch_flag = TTY_OVERRUN;
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}
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if (status & port->ignore_status_mask)
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continue;
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uart_insert_char(port, status, UA_STATUS_OVERRUN_ERR, ch,
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ch_flag);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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tty_flip_buffer_push(&port->state->port);
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}
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static void digicolor_uart_tx(struct uart_port *port)
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{
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struct circ_buf *xmit = &port->state->xmit;
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unsigned long flags;
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if (digicolor_uart_tx_full(port))
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return;
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spin_lock_irqsave(&port->lock, flags);
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if (port->x_char) {
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writeb_relaxed(port->x_char, port->membase + UA_EMI_REC);
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port->icount.tx++;
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port->x_char = 0;
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goto out;
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}
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if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
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digicolor_uart_stop_tx(port);
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goto out;
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}
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while (!uart_circ_empty(xmit)) {
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writeb(xmit->buf[xmit->tail], port->membase + UA_EMI_REC);
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xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
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port->icount.tx++;
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if (digicolor_uart_tx_full(port))
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break;
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}
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if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
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uart_write_wakeup(port);
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out:
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static irqreturn_t digicolor_uart_int(int irq, void *dev_id)
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{
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struct uart_port *port = dev_id;
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u8 int_status = readb_relaxed(port->membase + UA_INT_STATUS);
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writeb_relaxed(UA_INT_RX | UA_INT_TX,
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port->membase + UA_INTFLAG_CLEAR);
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if (int_status & UA_INT_RX)
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digicolor_uart_rx(port);
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if (int_status & UA_INT_TX)
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digicolor_uart_tx(port);
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return IRQ_HANDLED;
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}
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static unsigned int digicolor_uart_tx_empty(struct uart_port *port)
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{
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u8 status = readb_relaxed(port->membase + UA_STATUS);
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return (status & UA_STATUS_TX_READY) ? TIOCSER_TEMT : 0;
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}
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static unsigned int digicolor_uart_get_mctrl(struct uart_port *port)
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{
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return TIOCM_CTS;
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}
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static void digicolor_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
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{
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}
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static void digicolor_uart_break_ctl(struct uart_port *port, int state)
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{
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}
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static int digicolor_uart_startup(struct uart_port *port)
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{
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struct digicolor_port *dp =
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container_of(port, struct digicolor_port, port);
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writeb_relaxed(UA_ENABLE_ENABLE, port->membase + UA_ENABLE);
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writeb_relaxed(UA_CONTROL_SOFT_RESET, port->membase + UA_CONTROL);
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writeb_relaxed(0, port->membase + UA_CONTROL);
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writeb_relaxed(UA_CONFIG_FIFO_RX_FIFO_MODE
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| UA_CONFIG_FIFO_TX_FIFO_MODE | UA_CONFIG_FIFO_RX_THRESH,
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port->membase + UA_CONFIG_FIFO);
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writeb_relaxed(UA_STATUS_FIFO_RX_INT_ALMOST,
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port->membase + UA_STATUS_FIFO);
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writeb_relaxed(UA_CONTROL_RX_ENABLE | UA_CONTROL_TX_ENABLE,
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port->membase + UA_CONTROL);
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writeb_relaxed(UA_INT_TX | UA_INT_RX,
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port->membase + UA_INT_ENABLE);
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schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
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return 0;
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}
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static void digicolor_uart_shutdown(struct uart_port *port)
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{
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struct digicolor_port *dp =
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container_of(port, struct digicolor_port, port);
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writeb_relaxed(0, port->membase + UA_ENABLE);
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cancel_delayed_work_sync(&dp->rx_poll_work);
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}
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static void digicolor_uart_set_termios(struct uart_port *port,
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struct ktermios *termios,
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struct ktermios *old)
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{
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unsigned int baud, divisor;
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u8 config = 0;
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unsigned long flags;
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/* Mask termios capabilities we don't support */
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termios->c_cflag &= ~CMSPAR;
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termios->c_iflag &= ~(BRKINT | IGNBRK);
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/* Limit baud rates so that we don't need the fractional divider */
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baud = uart_get_baud_rate(port, termios, old,
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port->uartclk / (0x10000*16),
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port->uartclk / 256);
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divisor = uart_get_divisor(port, baud) - 1;
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switch (termios->c_cflag & CSIZE) {
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case CS7:
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break;
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case CS8:
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default:
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config |= UA_CONFIG_CHAR_LEN;
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break;
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}
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if (termios->c_cflag & CSTOPB)
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config |= UA_CONFIG_STOP_BITS;
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if (termios->c_cflag & PARENB) {
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config |= UA_CONFIG_PARITY;
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if (termios->c_cflag & PARODD)
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config |= UA_CONFIG_ODD_PARITY;
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}
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/* Set read status mask */
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port->read_status_mask = UA_STATUS_OVERRUN_ERR;
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if (termios->c_iflag & INPCK)
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port->read_status_mask |= UA_STATUS_PARITY_ERR
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| UA_STATUS_FRAME_ERR;
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/* Set status ignore mask */
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port->ignore_status_mask = 0;
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if (!(termios->c_cflag & CREAD))
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port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR
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| UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR;
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spin_lock_irqsave(&port->lock, flags);
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uart_update_timeout(port, termios->c_cflag, baud);
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writeb_relaxed(config, port->membase + UA_CONFIG);
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writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO);
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writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI);
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spin_unlock_irqrestore(&port->lock, flags);
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}
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static const char *digicolor_uart_type(struct uart_port *port)
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{
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return (port->type == PORT_DIGICOLOR) ? "DIGICOLOR USART" : NULL;
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}
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static void digicolor_uart_config_port(struct uart_port *port, int flags)
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{
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if (flags & UART_CONFIG_TYPE)
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port->type = PORT_DIGICOLOR;
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}
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static void digicolor_uart_release_port(struct uart_port *port)
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{
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}
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static int digicolor_uart_request_port(struct uart_port *port)
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{
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return 0;
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}
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static const struct uart_ops digicolor_uart_ops = {
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.tx_empty = digicolor_uart_tx_empty,
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.set_mctrl = digicolor_uart_set_mctrl,
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.get_mctrl = digicolor_uart_get_mctrl,
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.stop_tx = digicolor_uart_stop_tx,
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.start_tx = digicolor_uart_start_tx,
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.stop_rx = digicolor_uart_stop_rx,
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.break_ctl = digicolor_uart_break_ctl,
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.startup = digicolor_uart_startup,
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.shutdown = digicolor_uart_shutdown,
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.set_termios = digicolor_uart_set_termios,
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.type = digicolor_uart_type,
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.config_port = digicolor_uart_config_port,
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.release_port = digicolor_uart_release_port,
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.request_port = digicolor_uart_request_port,
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};
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static void digicolor_uart_console_putchar(struct uart_port *port, int ch)
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{
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while (digicolor_uart_tx_full(port))
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cpu_relax();
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writeb_relaxed(ch, port->membase + UA_EMI_REC);
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}
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static void digicolor_uart_console_write(struct console *co, const char *c,
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unsigned n)
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{
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struct uart_port *port = digicolor_ports[co->index];
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u8 status;
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unsigned long flags;
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int locked = 1;
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if (oops_in_progress)
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locked = spin_trylock_irqsave(&port->lock, flags);
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else
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spin_lock_irqsave(&port->lock, flags);
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uart_console_write(port, c, n, digicolor_uart_console_putchar);
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if (locked)
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spin_unlock_irqrestore(&port->lock, flags);
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/* Wait for transmitter to become empty */
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do {
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status = readb_relaxed(port->membase + UA_STATUS);
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} while ((status & UA_STATUS_TX_READY) == 0);
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}
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static int digicolor_uart_console_setup(struct console *co, char *options)
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{
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int baud = 115200, bits = 8, parity = 'n', flow = 'n';
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struct uart_port *port;
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if (co->index < 0 || co->index >= DIGICOLOR_USART_NR)
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return -EINVAL;
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port = digicolor_ports[co->index];
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if (!port)
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return -ENODEV;
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if (options)
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uart_parse_options(options, &baud, &parity, &bits, &flow);
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return uart_set_options(port, co, baud, parity, bits, flow);
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}
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static struct console digicolor_console = {
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.name = "ttyS",
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.device = uart_console_device,
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.write = digicolor_uart_console_write,
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.setup = digicolor_uart_console_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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static struct uart_driver digicolor_uart = {
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.driver_name = "digicolor-usart",
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.dev_name = "ttyS",
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.nr = DIGICOLOR_USART_NR,
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};
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static int digicolor_uart_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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int irq, ret, index;
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struct digicolor_port *dp;
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struct resource *res;
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struct clk *uart_clk;
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if (!np) {
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dev_err(&pdev->dev, "Missing device tree node\n");
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return -ENXIO;
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}
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index = of_alias_get_id(np, "serial");
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if (index < 0 || index >= DIGICOLOR_USART_NR)
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return -EINVAL;
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dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
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if (!dp)
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return -ENOMEM;
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uart_clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(uart_clk))
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return PTR_ERR(uart_clk);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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dp->port.mapbase = res->start;
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dp->port.membase = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(dp->port.membase))
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return PTR_ERR(dp->port.membase);
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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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dp->port.irq = irq;
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dp->port.iotype = UPIO_MEM;
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dp->port.uartclk = clk_get_rate(uart_clk);
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dp->port.fifosize = 16;
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dp->port.dev = &pdev->dev;
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dp->port.ops = &digicolor_uart_ops;
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dp->port.line = index;
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dp->port.type = PORT_DIGICOLOR;
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spin_lock_init(&dp->port.lock);
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digicolor_ports[index] = &dp->port;
|
|
platform_set_drvdata(pdev, &dp->port);
|
|
|
|
INIT_DELAYED_WORK(&dp->rx_poll_work, digicolor_rx_poll);
|
|
|
|
ret = devm_request_irq(&pdev->dev, dp->port.irq, digicolor_uart_int, 0,
|
|
dev_name(&pdev->dev), &dp->port);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return uart_add_one_port(&digicolor_uart, &dp->port);
|
|
}
|
|
|
|
static int digicolor_uart_remove(struct platform_device *pdev)
|
|
{
|
|
struct uart_port *port = platform_get_drvdata(pdev);
|
|
|
|
uart_remove_one_port(&digicolor_uart, port);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id digicolor_uart_dt_ids[] = {
|
|
{ .compatible = "cnxt,cx92755-usart", },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(of, digicolor_uart_dt_ids);
|
|
|
|
static struct platform_driver digicolor_uart_platform = {
|
|
.driver = {
|
|
.name = "digicolor-usart",
|
|
.of_match_table = of_match_ptr(digicolor_uart_dt_ids),
|
|
},
|
|
.probe = digicolor_uart_probe,
|
|
.remove = digicolor_uart_remove,
|
|
};
|
|
|
|
static int __init digicolor_uart_init(void)
|
|
{
|
|
int ret;
|
|
|
|
if (IS_ENABLED(CONFIG_SERIAL_CONEXANT_DIGICOLOR_CONSOLE)) {
|
|
digicolor_uart.cons = &digicolor_console;
|
|
digicolor_console.data = &digicolor_uart;
|
|
}
|
|
|
|
ret = uart_register_driver(&digicolor_uart);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return platform_driver_register(&digicolor_uart_platform);
|
|
}
|
|
module_init(digicolor_uart_init);
|
|
|
|
static void __exit digicolor_uart_exit(void)
|
|
{
|
|
platform_driver_unregister(&digicolor_uart_platform);
|
|
uart_unregister_driver(&digicolor_uart);
|
|
}
|
|
module_exit(digicolor_uart_exit);
|
|
|
|
MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
|
|
MODULE_DESCRIPTION("Conexant Digicolor USART serial driver");
|
|
MODULE_LICENSE("GPL");
|