serial: 8250_ingenic: support for Ingenic SoC UARTs

Introduce a driver suitable for use with the UARTs present in
Ingenic SoCs such as the JZ4740 & JZ4780. These are described as being
ns16550 compatible but aren't quite - they require the setting of an
extra bit in the FCR register to enable the UART module. The serial_out
implementation is the same as that in arch/mips/jz4740/serial.c - which
will shortly be removed.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-serial@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: John Crispin <blogic@openwrt.org>
Patchwork: https://patchwork.linux-mips.org/patch/10159/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2015-05-24 16:11:44 +01:00 committed by Ralf Baechle
parent 98fd25e7ea
commit 0cf985f487
3 changed files with 278 additions and 0 deletions

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@ -0,0 +1,266 @@
/*
* Copyright (C) 2010 Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2015 Imagination Technologies
*
* Ingenic SoC UART support
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/clk.h>
#include <linux/console.h>
#include <linux/io.h>
#include <linux/libfdt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/platform_device.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
struct ingenic_uart_data {
struct clk *clk_module;
struct clk *clk_baud;
int line;
};
#define UART_FCR_UME BIT(4)
static struct earlycon_device *early_device;
static uint8_t __init early_in(struct uart_port *port, int offset)
{
return readl(port->membase + (offset << 2));
}
static void __init early_out(struct uart_port *port, int offset, uint8_t value)
{
writel(value, port->membase + (offset << 2));
}
static void __init ingenic_early_console_putc(struct uart_port *port, int c)
{
uint8_t lsr;
do {
lsr = early_in(port, UART_LSR);
} while ((lsr & UART_LSR_TEMT) == 0);
early_out(port, UART_TX, c);
}
static void __init ingenic_early_console_write(struct console *console,
const char *s, unsigned int count)
{
uart_console_write(&early_device->port, s, count,
ingenic_early_console_putc);
}
static void __init ingenic_early_console_setup_clock(struct earlycon_device *dev)
{
void *fdt = initial_boot_params;
const __be32 *prop;
int offset;
offset = fdt_path_offset(fdt, "/ext");
if (offset < 0)
return;
prop = fdt_getprop(fdt, offset, "clock-frequency", NULL);
if (!prop)
return;
dev->port.uartclk = be32_to_cpup(prop);
}
static int __init ingenic_early_console_setup(struct earlycon_device *dev,
const char *opt)
{
struct uart_port *port = &dev->port;
unsigned int baud, divisor;
if (!dev->port.membase)
return -ENODEV;
ingenic_early_console_setup_clock(dev);
baud = dev->baud ?: 115200;
divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
early_out(port, UART_IER, 0);
early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
early_out(port, UART_DLL, 0);
early_out(port, UART_DLM, 0);
early_out(port, UART_LCR, UART_LCR_WLEN8);
early_out(port, UART_FCR, UART_FCR_UME | UART_FCR_CLEAR_XMIT |
UART_FCR_CLEAR_RCVR | UART_FCR_ENABLE_FIFO);
early_out(port, UART_MCR, UART_MCR_RTS | UART_MCR_DTR);
early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
early_out(port, UART_DLL, divisor & 0xff);
early_out(port, UART_DLM, (divisor >> 8) & 0xff);
early_out(port, UART_LCR, UART_LCR_WLEN8);
early_device = dev;
dev->con->write = ingenic_early_console_write;
return 0;
}
EARLYCON_DECLARE(jz4740_uart, ingenic_early_console_setup);
OF_EARLYCON_DECLARE(jz4740_uart, "ingenic,jz4740-uart",
ingenic_early_console_setup);
EARLYCON_DECLARE(jz4775_uart, ingenic_early_console_setup);
OF_EARLYCON_DECLARE(jz4775_uart, "ingenic,jz4775-uart",
ingenic_early_console_setup);
EARLYCON_DECLARE(jz4780_uart, ingenic_early_console_setup);
OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart",
ingenic_early_console_setup);
static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
{
switch (offset) {
case UART_FCR:
/* UART module enable */
value |= UART_FCR_UME;
break;
case UART_IER:
value |= (value & 0x4) << 2;
break;
default:
break;
}
writeb(value, p->membase + (offset << p->regshift));
}
static int ingenic_uart_probe(struct platform_device *pdev)
{
struct uart_8250_port uart = {};
struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
struct ingenic_uart_data *data;
int err, line;
if (!regs || !irq) {
dev_err(&pdev->dev, "no registers/irq defined\n");
return -EINVAL;
}
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
spin_lock_init(&uart.port.lock);
uart.port.type = PORT_16550;
uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
uart.port.iotype = UPIO_MEM;
uart.port.mapbase = regs->start;
uart.port.regshift = 2;
uart.port.serial_out = ingenic_uart_serial_out;
uart.port.irq = irq->start;
uart.port.dev = &pdev->dev;
/* Check for a fixed line number */
line = of_alias_get_id(pdev->dev.of_node, "serial");
if (line >= 0)
uart.port.line = line;
uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
resource_size(regs));
if (!uart.port.membase)
return -ENOMEM;
data->clk_module = devm_clk_get(&pdev->dev, "module");
if (IS_ERR(data->clk_module)) {
err = PTR_ERR(data->clk_module);
if (err != -EPROBE_DEFER)
dev_err(&pdev->dev,
"unable to get module clock: %d\n", err);
return err;
}
data->clk_baud = devm_clk_get(&pdev->dev, "baud");
if (IS_ERR(data->clk_baud)) {
err = PTR_ERR(data->clk_baud);
if (err != -EPROBE_DEFER)
dev_err(&pdev->dev,
"unable to get baud clock: %d\n", err);
return err;
}
err = clk_prepare_enable(data->clk_module);
if (err) {
dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
goto out;
}
err = clk_prepare_enable(data->clk_baud);
if (err) {
dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
goto out_disable_moduleclk;
}
uart.port.uartclk = clk_get_rate(data->clk_baud);
data->line = serial8250_register_8250_port(&uart);
if (data->line < 0) {
err = data->line;
goto out_disable_baudclk;
}
platform_set_drvdata(pdev, data);
return 0;
out_disable_baudclk:
clk_disable_unprepare(data->clk_baud);
out_disable_moduleclk:
clk_disable_unprepare(data->clk_module);
out:
return err;
}
static int ingenic_uart_remove(struct platform_device *pdev)
{
struct ingenic_uart_data *data = platform_get_drvdata(pdev);
serial8250_unregister_port(data->line);
clk_disable_unprepare(data->clk_module);
clk_disable_unprepare(data->clk_baud);
return 0;
}
static const struct of_device_id of_match[] = {
{ .compatible = "ingenic,jz4740-uart" },
{ .compatible = "ingenic,jz4775-uart" },
{ .compatible = "ingenic,jz4780-uart" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, of_match);
static struct platform_driver ingenic_uart_platform_driver = {
.driver = {
.name = "ingenic-uart",
.owner = THIS_MODULE,
.of_match_table = of_match,
},
.probe = ingenic_uart_probe,
.remove = ingenic_uart_remove,
};
module_platform_driver(ingenic_uart_platform_driver);
MODULE_AUTHOR("Paul Burton");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Ingenic SoC UART driver");

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@ -342,3 +342,12 @@ config SERIAL_8250_MT6577
help
If you have a Mediatek based board and want to use the
serial port, say Y to this option. If unsure, say N.
config SERIAL_8250_INGENIC
bool "Support for Ingenic SoC serial ports"
depends on SERIAL_8250_CONSOLE && OF_FLATTREE
select LIBFDT
select SERIAL_EARLYCON
help
If you have a system using an Ingenic SoC and wish to make use of
its UARTs, say Y to this option. If unsure, say N.

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@ -23,3 +23,6 @@ obj-$(CONFIG_SERIAL_8250_EM) += 8250_em.o
obj-$(CONFIG_SERIAL_8250_OMAP) += 8250_omap.o
obj-$(CONFIG_SERIAL_8250_FINTEK) += 8250_fintek.o
obj-$(CONFIG_SERIAL_8250_MT6577) += 8250_mtk.o
obj-$(CONFIG_SERIAL_8250_INGENIC) += 8250_ingenic.o
CFLAGS_8250_ingenic.o += -I$(srctree)/scripts/dtc/libfdt