[RFC 08/11] tty: serial: sunplus: Implement full UART driver

From: Andreas FÃrber
Date: Sun Mar 08 2020 - 12:33:12 EST


Signed-off-by: Andreas FÃrber <afaerber@xxxxxxx>
---
drivers/tty/serial/Kconfig | 4 +-
drivers/tty/serial/sunplus-uart.c | 680 ++++++++++++++++++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +
3 files changed, 685 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index ac6dce75c2f3..a178500a6bb5 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1563,7 +1563,7 @@ config SERIAL_MILBEAUT_USIO_CONSOLE
single user mode).

config SERIAL_PLUS1
- bool "Sunplus Plus1 serial port support"
+ tristate "Sunplus Plus1 serial port support"
depends on ARCH_SUNPLUS || COMPILE_TEST
select SERIAL_CORE
help
@@ -1579,7 +1579,7 @@ config SERIAL_PLUS1_CONSOLE
default y
help
Say 'Y' here if you wish to use Sunplus SP7021 UART
- as the system console. Only earlycon is implemented currently.
+ as the system console.

endmenu

diff --git a/drivers/tty/serial/sunplus-uart.c b/drivers/tty/serial/sunplus-uart.c
index 959dfab5e07b..9b9442acde9a 100644
--- a/drivers/tty/serial/sunplus-uart.c
+++ b/drivers/tty/serial/sunplus-uart.c
@@ -4,6 +4,7 @@
*/

#include <linux/bitops.h>
+#include <linux/clk.h>
#include <linux/console.h>
#include <linux/io.h>
#include <linux/module.h>
@@ -11,11 +12,71 @@
#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#define PLUS1_UART_PORT_NUM 5
+#define PLUS1_UART_DEV_NAME "ttySP"

#define REG_DATA 0x00
#define REG_LSR 0x04
+#define REG_MSR 0x08
+#define REG_LCR 0x0c
+#define REG_MCR 0x10
+#define REG_DIV_L 0x14
+#define REG_DIV_H 0x18
+#define REG_ISC 0x1c
+#define REG_TX_RESIDUE 0x20
+#define REG_RX_RESIDUE 0x24
+#define REG_RX_THRESHOLD 0x28
+#define REG_CLK_SRC 0x2c

#define PLUS1_UART_LSR_TX BIT(0)
+#define PLUS1_UART_LSR_RX BIT(1)
+#define PLUS1_UART_LSR_PE BIT(2)
+#define PLUS1_UART_LSR_OE BIT(3)
+#define PLUS1_UART_LSR_FE BIT(4)
+#define PLUS1_UART_LSR_BC BIT(5)
+#define PLUS1_UART_LSR_TXE BIT(6)
+
+#define PLUS1_UART_LCR_WL_MASK GENMASK(1, 0)
+#define PLUS1_UART_LCR_WL5 (0x0 << 0)
+#define PLUS1_UART_LCR_WL6 (0x1 << 0)
+#define PLUS1_UART_LCR_WL7 (0x2 << 0)
+#define PLUS1_UART_LCR_WL8 (0x3 << 0)
+#define PLUS1_UART_LCR_ST BIT(2)
+#define PLUS1_UART_LCR_PE BIT(3)
+#define PLUS1_UART_LCR_PR BIT(4)
+#define PLUS1_UART_LCR_BC BIT(5)
+
+#define PLUS1_UART_MCR_DTS BIT(0)
+#define PLUS1_UART_MCR_RTS BIT(1)
+#define PLUS1_UART_MCR_DCD BIT(2)
+#define PLUS1_UART_MCR_RI BIT(3)
+#define PLUS1_UART_MCR_LB BIT(4)
+#define PLUS1_UART_MCR_AR BIT(5)
+#define PLUS1_UART_MCR_AC BIT(6)
+#define PLUS1_UART_MCR_AT BIT(7)
+
+#define PLUS1_UART_ISC_TX BIT(0)
+#define PLUS1_UART_ISC_RX BIT(1)
+#define PLUS1_UART_ISC_LS BIT(2)
+#define PLUS1_UART_ISC_MS BIT(3)
+#define PLUS1_UART_ISC_TXM BIT(4)
+#define PLUS1_UART_ISC_RXM BIT(5)
+#define PLUS1_UART_ISC_LSM BIT(6)
+#define PLUS1_UART_ISC_MSM BIT(7)
+
+static struct uart_driver plus1_uart_driver;
+
+struct plus1_uart_port {
+ struct uart_port port;
+ struct clk *clk;
+};
+
+#define to_plus1_uart_port(prt) container_of(prt, struct plus1_uart_port, prt)
+
+static struct plus1_uart_port *plus1_uart_ports[PLUS1_UART_PORT_NUM];

static inline void plus1_uart_write(struct uart_port *port, unsigned int off, u32 val)
{
@@ -27,6 +88,447 @@ static inline u32 plus1_uart_read(struct uart_port *port, unsigned int off)
return readl_relaxed(port->membase + off);
}

+static void plus1_uart_break_ctl(struct uart_port *port, int ctl)
+{
+ unsigned long flags;
+ u32 lcr;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ lcr = plus1_uart_read(port, REG_LCR);
+ if (ctl)
+ lcr |= PLUS1_UART_LCR_BC;
+ else
+ lcr &= ~PLUS1_UART_LCR_BC;
+ plus1_uart_write(port, REG_LCR, lcr);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void plus1_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ u32 mcr;
+
+ mcr = plus1_uart_read(port, REG_MCR);
+
+ if (mctrl & TIOCM_DTR)
+ mcr |= PLUS1_UART_MCR_DTS;
+ else
+ mcr &= ~PLUS1_UART_MCR_DTS;
+
+ if (mctrl & TIOCM_RTS)
+ mcr |= PLUS1_UART_MCR_RTS;
+ else
+ mcr &= ~PLUS1_UART_MCR_RTS;
+
+ if (mctrl & TIOCM_CAR)
+ mcr |= PLUS1_UART_MCR_DCD;
+ else
+ mcr &= ~PLUS1_UART_MCR_DCD;
+
+ if (mctrl & TIOCM_RI)
+ mcr |= PLUS1_UART_MCR_RI;
+ else
+ mcr &= ~PLUS1_UART_MCR_RI;
+
+ if (mctrl & TIOCM_LOOP)
+ mcr |= PLUS1_UART_MCR_LB;
+ else
+ mcr &= ~PLUS1_UART_MCR_LB;
+
+ plus1_uart_write(port, REG_MCR, mcr);
+}
+
+static unsigned int plus1_uart_get_mctrl(struct uart_port *port)
+{
+ unsigned int mctrl = 0;
+ u32 mcr;
+
+ mcr = plus1_uart_read(port, REG_MCR);
+ if (mcr & PLUS1_UART_MCR_DTS)
+ mctrl |= TIOCM_DTR;
+ if (mcr & PLUS1_UART_MCR_RTS)
+ mctrl |= TIOCM_RTS;
+ if (mcr & PLUS1_UART_MCR_DCD)
+ mctrl |= TIOCM_CAR;
+ if (mcr & PLUS1_UART_MCR_RI)
+ mctrl |= TIOCM_RI;
+ if (mcr & PLUS1_UART_MCR_LB)
+ mctrl |= TIOCM_LOOP;
+ if (mcr & PLUS1_UART_MCR_AC)
+ mctrl |= TIOCM_CTS;
+ return mctrl;
+}
+
+static unsigned int plus1_uart_tx_empty(struct uart_port *port)
+{
+ unsigned long flags;
+ unsigned int ret;
+ u32 lsr;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ lsr = plus1_uart_read(port, REG_LSR);
+ ret = (lsr & PLUS1_UART_LSR_TXE) ? TIOCSER_TEMT : 0;
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return ret;
+}
+
+static void plus1_uart_stop_rx(struct uart_port *port)
+{
+ u32 isc;
+
+ isc = plus1_uart_read(port, REG_ISC);
+ isc &= ~PLUS1_UART_ISC_RXM;
+ plus1_uart_write(port, REG_ISC, isc);
+}
+
+static void plus1_uart_stop_tx(struct uart_port *port)
+{
+ u32 isc;
+
+ isc = plus1_uart_read(port, REG_ISC);
+ isc &= ~PLUS1_UART_ISC_TXM;
+ plus1_uart_write(port, REG_ISC, isc);
+}
+
+static void plus1_uart_start_tx(struct uart_port *port)
+{
+ u32 isc;
+
+ if (uart_tx_stopped(port)) {
+ plus1_uart_stop_tx(port);
+ return;
+ }
+
+ isc = plus1_uart_read(port, REG_ISC);
+ isc |= PLUS1_UART_ISC_TXM;
+ plus1_uart_write(port, REG_ISC, isc);
+}
+
+static void plus1_uart_send_chars(struct uart_port *port)
+{
+ struct circ_buf *xmit = &port->state->xmit;
+ unsigned int ch;
+
+ if (uart_tx_stopped(port))
+ return;
+
+ if (port->x_char) {
+ //while (!(plus1_uart_read(port, REG_LSR) & PLUS1_UART_LSR_TX))
+ // cpu_relax();
+ plus1_uart_write(port, REG_DATA, port->x_char);
+ port->icount.tx++;
+ port->x_char = 0;
+ }
+
+ while (plus1_uart_read(port, REG_LSR) & PLUS1_UART_LSR_TX) {
+ if (uart_circ_empty(xmit))
+ break;
+
+ ch = xmit->buf[xmit->tail];
+ plus1_uart_write(port, REG_DATA, ch);
+ xmit->tail = (xmit->tail + 1) & (SERIAL_XMIT_SIZE - 1);
+ port->icount.tx++;
+ }
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ if (uart_circ_empty(xmit))
+ plus1_uart_stop_tx(port);
+}
+
+static void plus1_uart_receive_chars(struct uart_port *port)
+{
+ u32 lsr, val;
+
+ lsr = plus1_uart_read(port, REG_LSR);
+ while (lsr & PLUS1_UART_LSR_RX) {
+ char flag = TTY_NORMAL;
+
+ if (lsr & PLUS1_UART_LSR_OE)
+ port->icount.overrun++;
+
+ if (lsr & PLUS1_UART_LSR_BC) {
+ port->icount.brk++;
+ flag = TTY_BREAK;
+ } else if (lsr & PLUS1_UART_LSR_PE) {
+ port->icount.parity++;
+ flag = TTY_PARITY;
+ } else if (lsr & PLUS1_UART_LSR_FE) {
+ port->icount.frame++;
+
+ lsr &= port->read_status_mask;
+ if (lsr & PLUS1_UART_LSR_FE)
+ flag = TTY_PARITY;
+ } else
+ port->icount.rx++;
+
+ val = plus1_uart_read(port, REG_DATA);
+ val &= 0xff;
+
+ if ((lsr & port->ignore_status_mask) == 0)
+ tty_insert_flip_char(&port->state->port, val, flag);
+
+ lsr = plus1_uart_read(port, REG_LSR);
+ }
+
+ spin_unlock(&port->lock);
+ tty_flip_buffer_push(&port->state->port);
+ spin_lock(&port->lock);
+}
+
+static irqreturn_t plus1_uart_irq(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ unsigned long flags;
+ u32 isc;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ isc = plus1_uart_read(port, REG_ISC);
+ if (isc & PLUS1_UART_ISC_RX)
+ plus1_uart_receive_chars(port);
+
+ isc = plus1_uart_read(port, REG_ISC);
+ if (isc & PLUS1_UART_ISC_TX)
+ plus1_uart_send_chars(port);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+static void plus1_uart_shutdown(struct uart_port *port)
+{
+ unsigned long flags;
+ u32 mcr;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ plus1_uart_write(port, REG_ISC, 0);
+
+ mcr = plus1_uart_read(port, REG_MCR);
+ mcr &= ~PLUS1_UART_MCR_AC;
+ plus1_uart_write(port, REG_MCR, mcr);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ free_irq(port->irq, port);
+}
+
+static int plus1_uart_startup(struct uart_port *port)
+{
+ unsigned long flags;
+ int ret;
+
+ ret = request_irq(port->irq, plus1_uart_irq, IRQF_TRIGGER_NONE,
+ "plus1-uart", port);
+ if (ret)
+ return ret;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ plus1_uart_write(port, REG_ISC, PLUS1_UART_ISC_RXM);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return 0;
+}
+
+static void plus1_uart_change_baudrate(struct plus1_uart_port *sp_port,
+ unsigned long baud)
+{
+ struct uart_port *port = &sp_port->port;
+ unsigned int clk;
+ unsigned int div, ext;
+
+ plus1_uart_write(port, REG_CLK_SRC, (baud > 115200) ? 0 : BIT(0));
+ if (baud > 115200)
+ clk = 202500000;
+ else
+ clk = port->uartclk;
+ clk += baud >> 1;
+ div = clk / baud;
+ ext = div & 0xf;
+ div >>= 4;
+ div--;
+ plus1_uart_write(port, REG_DIV_L, (ext << 12) | (div & 0xff));
+ plus1_uart_write(port, REG_DIV_H, div >> 8);
+}
+
+static void plus1_uart_set_termios(struct uart_port *port,
+ struct ktermios *termios,
+ struct ktermios *old)
+{
+ struct plus1_uart_port *sp_port = to_plus1_uart_port(port);
+ unsigned int baud;
+ u32 lcr, mcr;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ lcr = plus1_uart_read(port, REG_LCR);
+
+ lcr &= ~PLUS1_UART_LCR_WL_MASK;
+ switch (termios->c_cflag & CSIZE) {
+ case CS5:
+ lcr |= PLUS1_UART_LCR_WL5;
+ break;
+ case CS6:
+ lcr |= PLUS1_UART_LCR_WL6;
+ break;
+ case CS7:
+ lcr |= PLUS1_UART_LCR_WL7;
+ break;
+ case CS8:
+ default:
+ lcr |= PLUS1_UART_LCR_WL8;
+ break;
+ }
+
+ if (termios->c_cflag & CSTOPB)
+ lcr |= PLUS1_UART_LCR_ST;
+ else
+ lcr &= ~PLUS1_UART_LCR_ST;
+
+ if (termios->c_cflag & PARENB) {
+ lcr |= PLUS1_UART_LCR_PE;
+ } else
+ lcr &= ~PLUS1_UART_LCR_PE;
+
+ if ((termios->c_cflag & PARENB) && !(termios->c_cflag & PARODD))
+ lcr |= PLUS1_UART_LCR_PR;
+ else
+ lcr &= ~PLUS1_UART_LCR_PR;
+
+ plus1_uart_write(port, REG_LCR, lcr);
+
+ mcr = plus1_uart_read(port, REG_MCR);
+
+ if (termios->c_cflag & CRTSCTS)
+ mcr |= PLUS1_UART_MCR_AC | PLUS1_UART_MCR_AR;
+ else
+ mcr &= ~(PLUS1_UART_MCR_AC | PLUS1_UART_MCR_AR);
+
+ plus1_uart_write(port, REG_MCR, mcr);
+
+ baud = uart_get_baud_rate(port, termios, old, 0, 202500000 >> 4);
+ plus1_uart_change_baudrate(sp_port, baud);
+
+ /* Don't rewrite B0 */
+ if (tty_termios_baud_rate(termios))
+ tty_termios_encode_baud_rate(termios, baud, baud);
+
+ port->read_status_mask = 0;
+ if (termios->c_iflag & INPCK)
+ port->read_status_mask |= PLUS1_UART_LSR_PE | PLUS1_UART_LSR_FE;
+ if ((termios->c_iflag & BRKINT) || (termios->c_iflag & PARMRK))
+ port->read_status_mask |= PLUS1_UART_LSR_BC;
+
+ port->ignore_status_mask = 0;
+ if (termios->c_iflag & IGNPAR)
+ port->ignore_status_mask |= PLUS1_UART_LSR_PE | PLUS1_UART_LSR_FE;
+ if (termios->c_iflag & IGNBRK) {
+ port->ignore_status_mask |= PLUS1_UART_LSR_BC;
+ if (termios->c_iflag & IGNPAR)
+ port->ignore_status_mask |= PLUS1_UART_LSR_OE;
+ }
+
+ if (!(termios->c_cflag & CREAD))
+ plus1_uart_write(port, REG_RX_RESIDUE, 0);
+
+ uart_update_timeout(port, termios->c_cflag, baud);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void plus1_uart_release_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ struct resource *res;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return;
+
+ if (port->flags & UPF_IOREMAP) {
+ devm_release_mem_region(port->dev, port->mapbase,
+ resource_size(res));
+ devm_iounmap(port->dev, port->membase);
+ port->membase = NULL;
+ }
+}
+
+static int plus1_uart_request_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ struct resource *res;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENXIO;
+
+ if (!devm_request_mem_region(port->dev, port->mapbase,
+ resource_size(res), dev_name(port->dev)))
+ return -EBUSY;
+
+ if (port->flags & UPF_IOREMAP) {
+ port->membase = devm_ioremap(port->dev, port->mapbase,
+ resource_size(res));
+ if (!port->membase)
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static const char *plus1_uart_type(struct uart_port *port)
+{
+ return (port->type == PORT_PLUS1) ? "plus1-uart" : NULL;
+}
+
+static int plus1_uart_verify_port(struct uart_port *port,
+ struct serial_struct *ser)
+{
+ if (port->type != PORT_PLUS1)
+ return -EINVAL;
+
+ if (port->irq != ser->irq)
+ return -EINVAL;
+
+ return 0;
+}
+
+static void plus1_uart_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE) {
+ port->type = PORT_PLUS1;
+ plus1_uart_request_port(port);
+ }
+}
+
+static const struct uart_ops plus1_uart_ops = {
+ .break_ctl = plus1_uart_break_ctl,
+ .set_mctrl = plus1_uart_set_mctrl,
+ .get_mctrl = plus1_uart_get_mctrl,
+ .tx_empty = plus1_uart_tx_empty,
+ .start_tx = plus1_uart_start_tx,
+ .stop_rx = plus1_uart_stop_rx,
+ .stop_tx = plus1_uart_stop_tx,
+ .startup = plus1_uart_startup,
+ .shutdown = plus1_uart_shutdown,
+ .set_termios = plus1_uart_set_termios,
+ .type = plus1_uart_type,
+ .config_port = plus1_uart_config_port,
+ .request_port = plus1_uart_request_port,
+ .release_port = plus1_uart_release_port,
+ .verify_port = plus1_uart_verify_port,
+};
+
#ifdef CONFIG_SERIAL_PLUS1_CONSOLE

static void plus1_console_putchar(struct uart_port *port, int ch)
@@ -65,6 +567,57 @@ static void plus1_uart_port_write(struct uart_port *port, const char *s,
local_irq_restore(flags);
}

+static void plus1_uart_console_write(struct console *co, const char *s,
+ u_int count)
+{
+ struct plus1_uart_port *sp_port;
+
+ sp_port = plus1_uart_ports[co->index];
+ if (!sp_port)
+ return;
+
+ plus1_uart_port_write(&sp_port->port, s, count);
+}
+
+static int plus1_uart_console_setup(struct console *co, char *options)
+{
+ struct plus1_uart_port *sp_port;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+
+ if (co->index < 0 || co->index >= PLUS1_UART_PORT_NUM)
+ return -EINVAL;
+
+ sp_port = plus1_uart_ports[co->index];
+ if (!sp_port || !sp_port->port.membase)
+ return -ENODEV;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(&sp_port->port, co, baud, parity, bits, flow);
+}
+
+static struct console plus1_uart_console = {
+ .name = PLUS1_UART_DEV_NAME,
+ .write = plus1_uart_console_write,
+ .device = uart_console_device,
+ .setup = plus1_uart_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &plus1_uart_driver,
+};
+
+static int __init plus1_uart_console_init(void)
+{
+ register_console(&plus1_uart_console);
+
+ return 0;
+}
+console_initcall(plus1_uart_console_init);
+
static void plus1_uart_early_console_write(struct console *co,
const char *s,
u_int count)
@@ -87,4 +640,131 @@ plus1_uart_early_console_setup(struct earlycon_device *device, const char *opt)
OF_EARLYCON_DECLARE(sunplus, "sunplus,sp7021-uart",
plus1_uart_early_console_setup);

+#define PLUS1_UART_CONSOLE (&plus1_uart_console)
+#else
+#define PLUS1_UART_CONSOLE NULL
#endif
+
+static struct uart_driver plus1_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "plus1-uart",
+ .dev_name = PLUS1_UART_DEV_NAME,
+ .nr = PLUS1_UART_PORT_NUM,
+ .cons = PLUS1_UART_CONSOLE,
+};
+
+static int plus1_uart_probe(struct platform_device *pdev)
+{
+ struct resource *res_mem;
+ struct plus1_uart_port *sp_port;
+ int ret, irq;
+
+ if (pdev->dev.of_node)
+ pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
+
+ if (pdev->id < 0 || pdev->id >= PLUS1_UART_PORT_NUM) {
+ dev_err(&pdev->dev, "id %d out of range\n", pdev->id);
+ return -EINVAL;
+ }
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res_mem) {
+ dev_err(&pdev->dev, "could not get mem\n");
+ return -ENODEV;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ if (plus1_uart_ports[pdev->id]) {
+ dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
+ return -EBUSY;
+ }
+
+ sp_port = devm_kzalloc(&pdev->dev, sizeof(*sp_port), GFP_KERNEL);
+ if (!sp_port)
+ return -ENOMEM;
+
+ sp_port->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(sp_port->clk)) {
+ dev_err(&pdev->dev, "could not get clk\n");
+ return PTR_ERR(sp_port->clk);
+ }
+
+ sp_port->port.dev = &pdev->dev;
+ sp_port->port.line = pdev->id;
+ sp_port->port.type = PORT_PLUS1;
+ sp_port->port.iotype = UPIO_MEM;
+ sp_port->port.mapbase = res_mem->start;
+ sp_port->port.irq = irq;
+ sp_port->port.uartclk = clk_get_rate(sp_port->clk);
+ if (sp_port->port.uartclk == 0) {
+ dev_err(&pdev->dev, "clock rate is zero\n");
+ return -EINVAL;
+ }
+ sp_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY;
+ sp_port->port.x_char = 0;
+ sp_port->port.fifosize = 16;
+ sp_port->port.ops = &plus1_uart_ops;
+
+ plus1_uart_ports[pdev->id] = sp_port;
+ platform_set_drvdata(pdev, sp_port);
+
+ ret = uart_add_one_port(&plus1_uart_driver, &sp_port->port);
+ if (ret)
+ plus1_uart_ports[pdev->id] = NULL;
+
+ return ret;
+}
+
+static int plus1_uart_remove(struct platform_device *pdev)
+{
+ struct plus1_uart_port *sp_port = platform_get_drvdata(pdev);
+
+ uart_remove_one_port(&plus1_uart_driver, &sp_port->port);
+ plus1_uart_ports[pdev->id] = NULL;
+
+ return 0;
+}
+
+static const struct of_device_id plus1_uart_dt_matches[] = {
+ { .compatible = "sunplus,sp7021-uart" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, plus1_uart_dt_matches);
+
+static struct platform_driver plus1_uart_platform_driver = {
+ .probe = plus1_uart_probe,
+ .remove = plus1_uart_remove,
+ .driver = {
+ .name = "plus1-uart",
+ .of_match_table = plus1_uart_dt_matches,
+ },
+};
+
+static int __init plus1_uart_init(void)
+{
+ int ret;
+
+ ret = uart_register_driver(&plus1_uart_driver);
+ if (ret)
+ return ret;
+
+ ret = platform_driver_register(&plus1_uart_platform_driver);
+ if (ret)
+ uart_unregister_driver(&plus1_uart_driver);
+
+ return ret;
+}
+
+static void __exit plus1_uart_exit(void)
+{
+ platform_driver_unregister(&plus1_uart_platform_driver);
+ uart_unregister_driver(&plus1_uart_driver);
+}
+
+module_init(plus1_uart_init);
+module_exit(plus1_uart_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 8ec3dd742ea4..54c611b06735 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -293,4 +293,7 @@
/* Freescale LINFlexD UART */
#define PORT_LINFLEXUART 122

+/* SunPlus Plus1 UART */
+#define PORT_PLUS1 123
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
2.16.4