[PATCH v4 0/2] tty: serial: Add mediatek UART driver

[PATCH v4 0/2] tty: serial: Add mediatek UART driver

[Matthias Brugger]

This patch set adds support for the UART found in Mediatek SoCs.
The chip is a changed version of a 8250 controller.
Especially it introduces a new register called highspeed. The value
in this register has to be set depending on the baudrate. The value
in the register influences the way the divisor has to be calculated.

The patch series is build against v3.16-rc1 and tested on mt6589. Should
work as well on mt6577 and mt6582.

Thanks,
Matthias

Changes for v4:
- delete owner in platform driver instance
- pass plattform_device to mtk8250_probe_of
- reorganise probe function to error out early
- Fix DTS documentation

Changes for v3:
- use dev_warn instead of pr_warn
- use 8250_core function to update termios

Changes for v2:
- drop 8250_core capability extension for the chip
- encapsulate set_termios in the driver method

---

Matthias Brugger (2):
  tty: serial: 8250: Add Mediatek UART driver
  DTS: serial: Add bindings documention for the Mediatek UARTs

 .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++
 drivers/tty/serial/8250/8250_mtk.c                 |  294 ++++++++++++++++++++
 drivers/tty/serial/8250/Kconfig                    |    7 +
 drivers/tty/serial/8250/Makefile                   |    1 +
 4 files changed, 322 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
 create mode 100644 drivers/tty/serial/8250/8250_mtk.c

-- 
1.7.9.5

[PATCH v4 0/2] tty: serial: Add mediatek UART driver

[Matthias Brugger]

This patch set adds support for the UART found in Mediatek SoCs.
The chip is a changed version of a 8250 controller.
Especially it introduces a new register called highspeed. The value
in this register has to be set depending on the baudrate. The value
in the register influences the way the divisor has to be calculated.

The patch series is build against v3.16-rc1 and tested on mt6589. Should
work as well on mt6577 and mt6582.

Thanks,
Matthias

Changes for v4:
- delete owner in platform driver instance
- pass plattform_device to mtk8250_probe_of
- reorganise probe function to error out early
- Fix DTS documentation

Changes for v3:
- use dev_warn instead of pr_warn
- use 8250_core function to update termios

Changes for v2:
- drop 8250_core capability extension for the chip
- encapsulate set_termios in the driver method

---

Matthias Brugger (2):
  tty: serial: 8250: Add Mediatek UART driver
  DTS: serial: Add bindings documention for the Mediatek UARTs

 .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++
 drivers/tty/serial/8250/8250_mtk.c                 |  294 ++++++++++++++++++++
 drivers/tty/serial/8250/Kconfig                    |    7 +
 drivers/tty/serial/8250/Makefile                   |    1 +
 4 files changed, 322 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
 create mode 100644 drivers/tty/serial/8250/8250_mtk.c

-- 
1.7.9.5

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[PATCH v4 1/2] tty: serial: 8250: Add Mediatek UART driver

[Matthias Brugger]

The device has a highspeed register which influences the calcualtion of the
divisor. The chip lacks support for some baudrates. When requested, we set the
divisor to the next smaller baudrate and adjust the c_cflag accordingly.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
---
 drivers/tty/serial/8250/8250_mtk.c |  294 ++++++++++++++++++++++++++++++++++++
 drivers/tty/serial/8250/Kconfig    |    7 +
 drivers/tty/serial/8250/Makefile   |    1 +
 3 files changed, 302 insertions(+)
 create mode 100644 drivers/tty/serial/8250/8250_mtk.c

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
new file mode 100644
index 0000000..1c4b4bf
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -0,0 +1,294 @@
+/*
+ * Mediatek 8250 driver.
+ *
+ * Copyright (c) 2014 MundoReader S.L.
+ * Author: Matthias Brugger <matthias.bgg@gmail.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_reg.h>
+
+#include "8250.h"
+
+#define UART_MTK_HIGHS		0x09	/* Highspeed register */
+#define UART_MTK_SAMPLE_COUNT	0x0a	/* Sample count register */
+#define UART_MTK_SAMPLE_POINT	0x0b	/* Sample point register */
+#define MTK_UART_RATE_FIX	0x0d	/* UART Rate Fix Register */
+
+struct mtk8250_data {
+	int			line;
+	struct clk		*clk;
+};
+
+static void
+mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
+			struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned int baud, quot;
+
+	struct uart_8250_port *up =
+		container_of(port, struct uart_8250_port, port);
+
+	serial8250_do_set_termios(port, termios, old);
+
+	/*
+	 * Mediatek UARTs use an extra highspeed register (UART_MTK_HIGHS)
+	 *
+	 * We need to recalcualte the quot register, as the claculation depends
+	 * on the vaule in the highspeed register.
+	 *
+	 * Some baudrates are not supported by the chip, so we use the next
+	 * lower rate supported and update termios c_flag.
+	 *
+	 * If highspeed register is set to 3, we need to specify sample count
+	 * and sample point to increase accuracy. If not, we reset the
+	 * registers to their default values.
+	 */
+	baud = uart_get_baud_rate(port, termios, old,
+				  port->uartclk / 16 / 0xffff,
+				  port->uartclk / 16);
+
+	if (baud <= 115200) {
+		serial_port_out(port, UART_MTK_HIGHS, 0x0);
+		quot = uart_get_divisor(port, baud);
+	} else if (baud <= 576000) {
+		serial_port_out(port, UART_MTK_HIGHS, 0x2);
+
+		/* Set to next lower baudrate supported */
+		if ((baud == 500000) || (baud == 576000))
+			baud = 460800;
+		quot = DIV_ROUND_CLOSEST(port->uartclk, 4 * baud);
+	} else {
+		serial_port_out(port, UART_MTK_HIGHS, 0x3);
+
+		/* Set to highest baudrate supported */
+		if (baud >= 1152000)
+			baud = 921600;
+		quot = DIV_ROUND_CLOSEST(port->uartclk, 256 * baud);
+	}
+
+	/*
+	 * Ok, we're now changing the port state.  Do it with
+	 * interrupts disabled.
+	 */
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* set DLAB we have cval saved in up->lcr from the call to the core */
+	serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
+	serial_dl_write(up, quot);
+
+	/* reset DLAB */
+	serial_port_out(port, UART_LCR, up->lcr);
+
+	if (baud > 460800) {
+		unsigned int tmp;
+
+		tmp = DIV_ROUND_CLOSEST(port->uartclk, quot * baud);
+		serial_port_out(port, UART_MTK_SAMPLE_COUNT, tmp - 1);
+		serial_port_out(port, UART_MTK_SAMPLE_POINT,
+					(tmp - 2) >> 1);
+	} else {
+		serial_port_out(port, UART_MTK_SAMPLE_COUNT, 0x00);
+		serial_port_out(port, UART_MTK_SAMPLE_POINT, 0xff);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+
+static void
+mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
+{
+	if (!state)
+		pm_runtime_get_sync(port->dev);
+
+	serial8250_do_pm(port, state, old);
+
+	if (state)
+		pm_runtime_put_sync_suspend(port->dev);
+}
+
+static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
+			   struct mtk8250_data *data)
+{
+	int err;
+	struct device_node *np = pdev->dev.of_node;
+
+	data->clk = of_clk_get(np, 0);
+	if (IS_ERR(data->clk)) {
+		dev_warn(&pdev->dev, "Can't get timer clock\n");
+		return PTR_ERR(data->clk);
+	}
+
+	err = clk_prepare_enable(data->clk);
+	if (err) {
+		dev_warn(&pdev->dev, "Can't prepare clock\n");
+		clk_put(data->clk);
+		return err;
+	}
+	p->uartclk = clk_get_rate(data->clk);
+
+	return 0;
+}
+
+static int mtk8250_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 mtk8250_data *data;
+	int err;
+
+	if (!regs || !irq) {
+		dev_err(&pdev->dev, "no registers/irq defined\n");
+		return -EINVAL;
+	}
+
+	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
+					 resource_size(regs));
+	if (!uart.port.membase)
+		return -ENOMEM;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (pdev->dev.of_node) {
+		err = mtk8250_probe_of(pdev, &uart.port, data);
+		if (err)
+			return err;
+	} else
+		return -ENODEV;
+
+	spin_lock_init(&uart.port.lock);
+	uart.port.mapbase = regs->start;
+	uart.port.irq = irq->start;
+	uart.port.pm = mtk8250_do_pm;
+	uart.port.type = PORT_16550;
+	uart.port.flags = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT;
+	uart.port.dev = &pdev->dev;
+	uart.port.iotype = UPIO_MEM32;
+	uart.port.regshift = 2;
+	uart.port.private_data = data;
+	uart.port.set_termios = mtk8250_set_termios;
+
+	/* Disable Rate Fix function */
+	writel(0x0, uart.port.membase +
+			(MTK_UART_RATE_FIX << uart.port.regshift));
+
+	data->line = serial8250_register_8250_port(&uart);
+	if (data->line < 0)
+		return data->line;
+
+	platform_set_drvdata(pdev, data);
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+}
+
+static int mtk8250_remove(struct platform_device *pdev)
+{
+	struct mtk8250_data *data = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	serial8250_unregister_port(data->line);
+	if (!IS_ERR(data->clk)) {
+		clk_disable_unprepare(data->clk);
+		clk_put(data->clk);
+	}
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk8250_suspend(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	serial8250_suspend_port(data->line);
+
+	return 0;
+}
+
+static int mtk8250_resume(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	serial8250_resume_port(data->line);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+#ifdef CONFIG_PM_RUNTIME
+static int mtk8250_runtime_suspend(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	if (!IS_ERR(data->clk))
+		clk_disable_unprepare(data->clk);
+
+	return 0;
+}
+
+static int mtk8250_runtime_resume(struct device *dev)
+{
+	struct mtk8250_data *data = dev_get_drvdata(dev);
+
+	if (!IS_ERR(data->clk))
+		clk_prepare_enable(data->clk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops mtk8250_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(mtk8250_suspend, mtk8250_resume)
+	SET_RUNTIME_PM_OPS(mtk8250_runtime_suspend, mtk8250_runtime_resume,
+				NULL)
+};
+
+static const struct of_device_id mtk8250_of_match[] = {
+	{ .compatible = "mediatek,mt6577-uart" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk8250_of_match);
+
+static struct platform_driver mtk8250_platform_driver = {
+	.driver = {
+		.name		= "mt6577-uart",
+		.pm		= &mtk8250_pm_ops,
+		.of_match_table	= mtk8250_of_match,
+	},
+	.probe			= mtk8250_probe,
+	.remove			= mtk8250_remove,
+};
+module_platform_driver(mtk8250_platform_driver);
+
+MODULE_AUTHOR("Matthias Brugger");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Mediatek 8250 serial port driver");
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 349ee59..fac34aa 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -298,3 +298,10 @@ config SERIAL_8250_RT288X
 	  If you have a Ralink RT288x/RT305x SoC based board and want to use the
 	  serial port, say Y to this option. The driver can handle up to 2 serial
 	  ports. If unsure, say N.
+
+config SERIAL_8250_MT6577
+	bool "Mediatek serial port support"
+	depends on SERIAL_8250 && ARCH_MEDIATEK
+	help
+	  If you have a Mediatek based board and want to use the
+	  serial port, say Y to this option. If unsure, say N.
diff --git a/drivers/tty/serial/8250/Makefile b/drivers/tty/serial/8250/Makefile
index 36d68d0..6dcb46b 100644
--- a/drivers/tty/serial/8250/Makefile
+++ b/drivers/tty/serial/8250/Makefile
@@ -20,3 +20,4 @@ obj-$(CONFIG_SERIAL_8250_HUB6)		+= 8250_hub6.o
 obj-$(CONFIG_SERIAL_8250_FSL)		+= 8250_fsl.o
 obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.o
 obj-$(CONFIG_SERIAL_8250_EM)		+= 8250_em.o
+obj-$(CONFIG_SERIAL_8250_MT6577)	+= 8250_mtk.o
-- 
1.7.9.5

[PATCH v4 2/2] DTS: serial: Add bindings documention for the Mediatek UARTs

[Matthias Brugger]

This patch adds the devicetree documentation for the Mediatek UART.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
---
 .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt

diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
new file mode 100644
index 0000000..6ca0e15
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
@@ -0,0 +1,20 @@
+* Mediatek Universal Asynchronous Receiver/Transmitter (UART)
+
+Required properties:
+- compatible: "mediatek,mt6577-uart"
+  Compatibility with mt6577, mt6589, mt6582
+
+- reg: The base address of the UART register bank.
+
+- interrupts: A single interrupt specifier.
+
+- clocks: Clock driving the hardware.
+
+Example:
+
+	uart0: serial@11006000 {
+		compatible = "mediatek,mt6577-uart";
+		reg = <0x11006000 0x400>;
+		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
+		clocks = <&uart_clk>;
+	};
-- 
1.7.9.5

Re: [PATCH v4 0/2] tty: serial: Add mediatek UART driver

[Matthias Brugger]

[-- Attachment #1: Type: text/plain, Size: 1649 bytes --]

2014-08-12 16:12 GMT+02:00 Matthias Brugger <matthias.bgg@gmail.com>:

> This patch set adds support for the UART found in Mediatek SoCs.
> The chip is a changed version of a 8250 controller.
> Especially it introduces a new register called highspeed. The value
> in this register has to be set depending on the baudrate. The value
> in the register influences the way the divisor has to be calculated.
>
> The patch series is build against v3.16-rc1 and tested on mt6589. Should
> work as well on mt6577 and mt6582.
>
> Thanks,
> Matthias
>

Ping: Does anyone has any comments on this series?


>
> Changes for v4:
> - delete owner in platform driver instance
> - pass plattform_device to mtk8250_probe_of
> - reorganise probe function to error out early
> - Fix DTS documentation
>
> Changes for v3:
> - use dev_warn instead of pr_warn
> - use 8250_core function to update termios
>
> Changes for v2:
> - drop 8250_core capability extension for the chip
> - encapsulate set_termios in the driver method
>
> ---
>
> Matthias Brugger (2):
>   tty: serial: 8250: Add Mediatek UART driver
>   DTS: serial: Add bindings documention for the Mediatek UARTs
>
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++
>  drivers/tty/serial/8250/8250_mtk.c                 |  294
> ++++++++++++++++++++
>  drivers/tty/serial/8250/Kconfig                    |    7 +
>  drivers/tty/serial/8250/Makefile                   |    1 +
>  4 files changed, 322 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
>  create mode 100644 drivers/tty/serial/8250/8250_mtk.c
>
> --
> 1.7.9.5
>
>


-- 
motzblog.wordpress.com

[-- Attachment #2: Type: text/html, Size: 2433 bytes --]

Re: [PATCH v4 0/2] tty: serial: Add mediatek UART driver

[Matthias Brugger]

2014-08-12 16:12 GMT+02:00 Matthias Brugger <matthias.bgg@gmail.com>:
> This patch set adds support for the UART found in Mediatek SoCs.
> The chip is a changed version of a 8250 controller.
> Especially it introduces a new register called highspeed. The value
> in this register has to be set depending on the baudrate. The value
> in the register influences the way the divisor has to be calculated.
>
> The patch series is build against v3.16-rc1 and tested on mt6589. Should
> work as well on mt6577 and mt6582.
>
> Thanks,
> Matthias

Ping: Does anyone has any comment on this series?
Sorry, last mail was HTML by accident.

>
> Changes for v4:
> - delete owner in platform driver instance
> - pass plattform_device to mtk8250_probe_of
> - reorganise probe function to error out early
> - Fix DTS documentation
>
> Changes for v3:
> - use dev_warn instead of pr_warn
> - use 8250_core function to update termios
>
> Changes for v2:
> - drop 8250_core capability extension for the chip
> - encapsulate set_termios in the driver method
>
> ---
>
> Matthias Brugger (2):
>   tty: serial: 8250: Add Mediatek UART driver
>   DTS: serial: Add bindings documention for the Mediatek UARTs
>
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++
>  drivers/tty/serial/8250/8250_mtk.c                 |  294 ++++++++++++++++++++
>  drivers/tty/serial/8250/Kconfig                    |    7 +
>  drivers/tty/serial/8250/Makefile                   |    1 +
>  4 files changed, 322 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
>  create mode 100644 drivers/tty/serial/8250/8250_mtk.c
>
> --
> 1.7.9.5
>



-- 
motzblog.wordpress.com

Re: [PATCH v4 0/2] tty: serial: Add mediatek UART driver

[Matthias Brugger]

2014-08-12 16:12 GMT+02:00 Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
> This patch set adds support for the UART found in Mediatek SoCs.
> The chip is a changed version of a 8250 controller.
> Especially it introduces a new register called highspeed. The value
> in this register has to be set depending on the baudrate. The value
> in the register influences the way the divisor has to be calculated.
>
> The patch series is build against v3.16-rc1 and tested on mt6589. Should
> work as well on mt6577 and mt6582.
>
> Thanks,
> Matthias

Ping: Does anyone has any comment on this series?
Sorry, last mail was HTML by accident.

>
> Changes for v4:
> - delete owner in platform driver instance
> - pass plattform_device to mtk8250_probe_of
> - reorganise probe function to error out early
> - Fix DTS documentation
>
> Changes for v3:
> - use dev_warn instead of pr_warn
> - use 8250_core function to update termios
>
> Changes for v2:
> - drop 8250_core capability extension for the chip
> - encapsulate set_termios in the driver method
>
> ---
>
> Matthias Brugger (2):
>   tty: serial: 8250: Add Mediatek UART driver
>   DTS: serial: Add bindings documention for the Mediatek UARTs
>
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++
>  drivers/tty/serial/8250/8250_mtk.c                 |  294 ++++++++++++++++++++
>  drivers/tty/serial/8250/Kconfig                    |    7 +
>  drivers/tty/serial/8250/Makefile                   |    1 +
>  4 files changed, 322 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
>  create mode 100644 drivers/tty/serial/8250/8250_mtk.c
>
> --
> 1.7.9.5
>



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Re: [PATCH v4 2/2] DTS: serial: Add bindings documention for the Mediatek UARTs

[Mark Rutland]

On Tue, Aug 12, 2014 at 03:12:17PM +0100, Matthias Brugger wrote:
> This patch adds the devicetree documentation for the Mediatek UART.
> 
> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
> 
> diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> new file mode 100644
> index 0000000..6ca0e15
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> @@ -0,0 +1,20 @@
> +* Mediatek Universal Asynchronous Receiver/Transmitter (UART)
> +
> +Required properties:
> +- compatible: "mediatek,mt6577-uart"
> +  Compatibility with mt6577, mt6589, mt6582
> +
> +- reg: The base address of the UART register bank.
> +
> +- interrupts: A single interrupt specifier.
> +
> +- clocks: Clock driving the hardware.
> +
> +Example:
> +
> +	uart0: serial@11006000 {
> +		compatible = "mediatek,mt6577-uart";
> +		reg = <0x11006000 0x400>;
> +		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
> +		clocks = <&uart_clk>;
> +	};

This looks generally sane to me. It's simple and doesn't seem to have
any of the usual problems bindings have.

For the mt6577, mt6589, and mt6582, Do you expect to have specific
strings like:

compatible = "mediatek,mt6589-uart", "mediatek,mt6577-uart";

If so, could you update the compatible description to something like:

- compatible: should contain:
  * "mediatek,mt6589-uart" for ...
  * "mediatek,mt6582-uart" for ...
  * "mediatek,mt6577-uart" for all compatible UARTS (mt6589,mt6582,mt6577)

That way the driver just needs to recognise "mediatek,mt6577-uart" for
now but can have quirks later if we discover integration differences.

Cheers,
Mark.

Re: [PATCH v4 2/2] DTS: serial: Add bindings documention for the Mediatek UARTs

[Mark Rutland]

On Tue, Aug 12, 2014 at 03:12:17PM +0100, Matthias Brugger wrote:
> This patch adds the devicetree documentation for the Mediatek UART.
> 
> Signed-off-by: Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
> 
> diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> new file mode 100644
> index 0000000..6ca0e15
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> @@ -0,0 +1,20 @@
> +* Mediatek Universal Asynchronous Receiver/Transmitter (UART)
> +
> +Required properties:
> +- compatible: "mediatek,mt6577-uart"
> +  Compatibility with mt6577, mt6589, mt6582
> +
> +- reg: The base address of the UART register bank.
> +
> +- interrupts: A single interrupt specifier.
> +
> +- clocks: Clock driving the hardware.
> +
> +Example:
> +
> +	uart0: serial@11006000 {
> +		compatible = "mediatek,mt6577-uart";
> +		reg = <0x11006000 0x400>;
> +		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
> +		clocks = <&uart_clk>;
> +	};

This looks generally sane to me. It's simple and doesn't seem to have
any of the usual problems bindings have.

For the mt6577, mt6589, and mt6582, Do you expect to have specific
strings like:

compatible = "mediatek,mt6589-uart", "mediatek,mt6577-uart";

If so, could you update the compatible description to something like:

- compatible: should contain:
  * "mediatek,mt6589-uart" for ...
  * "mediatek,mt6582-uart" for ...
  * "mediatek,mt6577-uart" for all compatible UARTS (mt6589,mt6582,mt6577)

That way the driver just needs to recognise "mediatek,mt6577-uart" for
now but can have quirks later if we discover integration differences.

Cheers,
Mark.
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Re: [PATCH v4 1/2] tty: serial: 8250: Add Mediatek UART driver

[Mark Rutland]

[...]

> +static int mtk8250_probe_of(struct platform_device *pdev, struct uart_port *p,
> +			   struct mtk8250_data *data)
> +{
> +	int err;
> +	struct device_node *np = pdev->dev.of_node;
> +
> +	data->clk = of_clk_get(np, 0);
> +	if (IS_ERR(data->clk)) {
> +		dev_warn(&pdev->dev, "Can't get timer clock\n");
> +		return PTR_ERR(data->clk);
> +	}

Elsewhere you use devm_ interfaces. Can we not use devm_clk_get?

You might need to give the clock a name, but that's generally a good
thing -- it helps if a future revision has multiple clocks.

Mark.

Re: [PATCH v4 1/2] tty: serial: 8250: Add Mediatek UART driver

[Greg KH]

On Tue, Aug 12, 2014 at 04:12:16PM +0200, Matthias Brugger wrote:
> The device has a highspeed register which influences the calcualtion of the
> divisor. The chip lacks support for some baudrates. When requested, we set the
> divisor to the next smaller baudrate and adjust the c_cflag accordingly.
> 
> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
>  drivers/tty/serial/8250/8250_mtk.c |  294 ++++++++++++++++++++++++++++++++++++
>  drivers/tty/serial/8250/Kconfig    |    7 +
>  drivers/tty/serial/8250/Makefile   |    1 +
>  3 files changed, 302 insertions(+)
>  create mode 100644 drivers/tty/serial/8250/8250_mtk.c

This doesn't apply to my tree, care to refresh it against linux-next and
resend?

thanks,

greg k-h

Re: [PATCH v4 2/2] DTS: serial: Add bindings documention for the Mediatek UARTs

[Greg KH]

On Tue, Aug 12, 2014 at 04:12:17PM +0200, Matthias Brugger wrote:
> This patch adds the devicetree documentation for the Mediatek UART.
> 
> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
> 
> diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> new file mode 100644
> index 0000000..6ca0e15
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
> @@ -0,0 +1,20 @@
> +* Mediatek Universal Asynchronous Receiver/Transmitter (UART)
> +
> +Required properties:
> +- compatible: "mediatek,mt6577-uart"
> +  Compatibility with mt6577, mt6589, mt6582
> +
> +- reg: The base address of the UART register bank.
> +
> +- interrupts: A single interrupt specifier.
> +
> +- clocks: Clock driving the hardware.
> +
> +Example:
> +
> +	uart0: serial@11006000 {
> +		compatible = "mediatek,mt6577-uart";
> +		reg = <0x11006000 0x400>;
> +		interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
> +		clocks = <&uart_clk>;
> +	};
> -- 
> 1.7.9.5

Resend this one as well with the 1/2 patch please.

thanks,

greg k-h

Re: [PATCH v4 2/2] DTS: serial: Add bindings documention for the Mediatek UARTs

[Matthias Brugger]

2014-09-09 0:33 GMT+02:00 Greg KH <gregkh@linuxfoundation.org>:
> On Tue, Aug 12, 2014 at 04:12:17PM +0200, Matthias Brugger wrote:
>> This patch adds the devicetree documentation for the Mediatek UART.
>>
>> Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
>> ---
>>  .../devicetree/bindings/serial/mtk-uart.txt        |   20 ++++++++++++++++++++
>>  1 file changed, 20 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/serial/mtk-uart.txt
>>
>> diff --git a/Documentation/devicetree/bindings/serial/mtk-uart.txt b/Documentation/devicetree/bindings/serial/mtk-uart.txt
>> new file mode 100644
>> index 0000000..6ca0e15
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/serial/mtk-uart.txt
>> @@ -0,0 +1,20 @@
>> +* Mediatek Universal Asynchronous Receiver/Transmitter (UART)
>> +
>> +Required properties:
>> +- compatible: "mediatek,mt6577-uart"
>> +  Compatibility with mt6577, mt6589, mt6582
>> +
>> +- reg: The base address of the UART register bank.
>> +
>> +- interrupts: A single interrupt specifier.
>> +
>> +- clocks: Clock driving the hardware.
>> +
>> +Example:
>> +
>> +     uart0: serial@11006000 {
>> +             compatible = "mediatek,mt6577-uart";
>> +             reg = <0x11006000 0x400>;
>> +             interrupts = <GIC_SPI 51 IRQ_TYPE_LEVEL_LOW>;
>> +             clocks = <&uart_clk>;
>> +     };
>> --
>> 1.7.9.5
>
> Resend this one as well with the 1/2 patch please.

Ok, I will send v5 with the comments from Mark added.

>
> thanks,
>
> greg k-h



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