Re: [PATCH v5] serial: support for 16550A serial ports on LP-8x4x

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, 2015-12-16 at 00:04 +0300, Sergei Ianovich wrote:
> The patch adds support for 3 additional LP-8x4x built-in serial
> ports.
> 
> The device can also host up to 8 extension cards with 4 serial ports
> on each card for a total of 35 ports. However, I don't have
> the hardware to test extension cards, so they are not supported, yet.
> 

Few nitpicks, though everything looks okay.

> Signed-off-by: Sergei Ianovich <ynvich@gmail.com>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> CC: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
> ---
>    v4..v5
>    * constify struct of_device_id
>    * drop .owner from struct platform_driver
>    * rewrite set_termios() baud rate hadnling as suggested by Alan
> Cox
> 
>    v3..v4
>    * move DTS bindings to a different patch (8/21) as suggested by
>      Heikki Krogerus
> 
>    v2..v3
>    * no changes (except number 10/16 -> 12/21)
> 
>    v0..v2
>    * register platform driver instead of platform device
>    * use device tree
>    * use devm helpers where possible
> 
>  .../devicetree/bindings/serial/lp8x4x-serial.txt   |  35 +++++
>  drivers/tty/serial/8250/8250_lp8x4x.c              | 168
> +++++++++++++++++++++
>  drivers/tty/serial/8250/Kconfig                    |  12 ++
>  drivers/tty/serial/8250/Makefile                   |   1 +
>  4 files changed, 216 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/serial/lp8x4x-
> serial.txt
>  create mode 100644 drivers/tty/serial/8250/8250_lp8x4x.c
> 
> diff --git a/Documentation/devicetree/bindings/serial/lp8x4x-
> serial.txt b/Documentation/devicetree/bindings/serial/lp8x4x-
> serial.txt
> new file mode 100644
> index 0000000..5f9a4c1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/lp8x4x-serial.txt
> @@ -0,0 +1,35 @@
> +UART ports on ICP DAS LP-8x4x
> +
> +ICP DAS LP-8x4x contains three additional serial ports interfaced
> via
> +Analog Devices ADM213EA chips in addition to 3 serial ports on PXA
> CPU.
> +
> +Required properties:
> +- compatible : should be "icpdas,uart-lp8x4x"
> +
> +- reg : should provide 16 byte man IO memory region and 1 byte
> region for
> +	termios
> +
> +- interrupts : should provide interrupt
> +
> +- interrupt-parent : should provide a link to interrupt controller
> either
> +		     explicitly or implicitly from a parent node
> +
> +Examples (from pxa27x-lp8x4x.dts):
> +
> +		uart@9050 {
> +			compatible = "icpdas,uart-lp8x4x";
> +			reg = <0x9050 0x10
> +			       0x9030 0x02>;
> +			interrupt-parent = <&fpgairg>;
> +			interrupts = <13>;
> +			status = "okay";
> +		};
> +
> +		uart@9060 {
> +			compatible = "icpdas,uart-lp8x4x";
> +			reg = <0x9060 0x10
> +			       0x9032 0x02>;
> +			interrupt-parent = <&fpgairg>;
> +			interrupts = <14>;
> +			status = "okay";
> +		};
> diff --git a/drivers/tty/serial/8250/8250_lp8x4x.c
> b/drivers/tty/serial/8250/8250_lp8x4x.c
> new file mode 100644
> index 0000000..0e07220
> --- /dev/null
> +++ b/drivers/tty/serial/8250/8250_lp8x4x.c
> @@ -0,0 +1,168 @@
> +/*  linux/drivers/tty/serial/8250/8250_lp8x4x.c
> + *
> + *  Support for 16550A serial ports on ICP DAS LP-8x4x
> + *
> + *  Copyright (C) 2013 Sergei Ianovich <ynvich@gmail.com>
> + *
> + *  This program is free software; you can redistribute it and/or
> modify
> + *  it under the terms of the GNU General Public License version 2
> as
> + *  published by the Free Software Foundation.
> + */
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/module.h>
> +#include <linux/serial_8250.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +
> +struct lp8x4x_serial_data {
> +	int			line;
> +	void			*ios_mem;
> +};
> +
> +static void lp8x4x_serial_set_termios(struct uart_port *port,
> +		struct ktermios *termios, struct ktermios *old)
> +{
> +	unsigned int len;
> +	unsigned int baud;
> +	struct lp8x4x_serial_data *data = port->private_data;
> +
> +	serial8250_do_set_termios(port, termios, old);
> +
> +	switch (termios->c_cflag & CSIZE) {
> +	case CS5:
> +		len = 7;
> +		break;
> +	case CS6:
> +		len = 8;
> +		break;
> +	case CS7:
> +		len = 9;
> +		break;

> +	default:
> +	case CS8:

I would suggest to exchange those lines.

> +		len = 10;
> +		break;
> +	}
> +
> +	if (termios->c_cflag & CSTOPB)
> +		len++;
> +	if (termios->c_cflag & PARENB)
> +		len++;
> +	if (!(termios->c_cflag & PARODD))
> +		len++;
> +#ifdef CMSPAR
> +	if (termios->c_cflag & CMSPAR)
> +		len++;
> +#endif
> +
> +	len -= 9;
> +	len &= 3;
> +	len <<= 3;

> +	/*
> +	 * Ask the core to calculate the divisor for us.
> +	 */

Can it be one line?

> +	baud = tty_termios_baud_rate(termios);
> +
> +	switch (baud) {
> +	case 115200:
> +		len |= 7;
> +		break;
> +	case 57600:
> +		len |= 6;
> +		break;
> +	case 38400:
> +		len |= 5;
> +		break;
> +	case 19200:
> +		len |= 4;
> +		break;
> +	case 9600:
> +		len |= 3;
> +		break;
> +	case 4800:
> +		len |= 2;
> +		break;
> +	case 2400:
> +	default:
> +		len |= 1;
> +		break;
> +	};
> +	iowrite8(len, data->ios_mem);

writeb() ?

> +
> +}
> +
> +static const struct of_device_id lp8x4x_serial_dt_ids[] = {
> +	{ .compatible = "icpdas,uart-lp8x4x", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, lp8x4x_serial_dt_ids);
> +
> +static int lp8x4x_serial_probe(struct platform_device *pdev)
> +{
> +	struct uart_8250_port uart = {};
> +	struct lp8x4x_serial_data *data;
> +	struct resource *mmres, *mires, *irqres;
> +	int ret;
> +
> +	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	mires = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> +	if (!mmres || !mires || !irqres)
> +		return -ENODEV;
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->ios_mem = devm_ioremap_resource(&pdev->dev, mires);
> +	if (!data->ios_mem)
> +		return -EFAULT;
> +
> +	uart.port.iotype = UPIO_MEM;
> +	uart.port.mapbase = mmres->start;
> +	uart.port.iobase = mmres->start;
> +	uart.port.regshift = 1;
> +	uart.port.irq = irqres->start;
> +	uart.port.flags = UPF_IOREMAP;
> +	uart.port.dev = &pdev->dev;
> +	uart.port.uartclk = 14745600;
> +	uart.port.set_termios = lp8x4x_serial_set_termios;
> +	uart.port.private_data = data;
> +
> +	ret = serial8250_register_8250_port(&uart);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->line = ret;
> +
> +	platform_set_drvdata(pdev, data);
> +
> +	return 0;
> +}
> +
> +static int lp8x4x_serial_remove(struct platform_device *pdev)
> +{
> +	struct lp8x4x_serial_data *data =
> platform_get_drvdata(pdev);
> +
> +	serial8250_unregister_port(data->line);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver lp8x4x_serial_driver = {
> +	.probe          = lp8x4x_serial_probe,
> +	.remove         = lp8x4x_serial_remove,
> +
> +	.driver		= {
> +		.name	= "uart-lp8x4x",
> +		.of_match_table = lp8x4x_serial_dt_ids,
> +	},
> +};
> +
> +module_platform_driver(lp8x4x_serial_driver);
> +
> +MODULE_AUTHOR("Sergei Ianovich");
> +MODULE_DESCRIPTION("8250 serial port module for LP-8x4x");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/tty/serial/8250/Kconfig
> b/drivers/tty/serial/8250/Kconfig
> index 48b6253..00eb6b0 100644
> --- a/drivers/tty/serial/8250/Kconfig
> +++ b/drivers/tty/serial/8250/Kconfig
> @@ -387,3 +387,15 @@ config SERIAL_8250_PXA
>  	  can enable its onboard serial ports by enabling this
> option.
>  
>  	  If you choose M here, the module name will be 8250_pxa.
> +
> +config SERIAL_8250_LP8X4X
> +	tristate "Support 16550A ports on ICP DAS LP-8x4x"
> +	depends on OF && SERIAL_8250 && SERIAL_8250_MANY_PORTS &&
> ARCH_PXA
> +	select LP8X4X_IRQ
> +	help
> +	  In addition to serial ports on PXA270 SoC, LP-8x4x has 1
> dual
> +	  RS232/RS485 port, 1 RS485 port and 1 RS232 port.
> +
> +	  Say N here, unless you plan to run this kernel on a LP-
> 8x4x system.
> +
> +	  If you choose M here, the module name will be 8250_lp8x4x.
> diff --git a/drivers/tty/serial/8250/Makefile
> b/drivers/tty/serial/8250/Makefile
> index 7e54413..8bdbf40 100644
> --- a/drivers/tty/serial/8250/Makefile
> +++ b/drivers/tty/serial/8250/Makefile
> @@ -18,6 +18,7 @@ obj-$(CONFIG_SERIAL_8250_ACCENT)	+=
> 8250_accent.o
>  obj-$(CONFIG_SERIAL_8250_BOCA)		+= 8250_boca.o
>  obj-$(CONFIG_SERIAL_8250_EXAR_ST16C554)	+=
> 8250_exar_st16c554.o
>  obj-$(CONFIG_SERIAL_8250_HUB6)		+= 8250_hub6.o
> +obj-$(CONFIG_SERIAL_8250_LP8X4X)	+= 8250_lp8x4x.o
>  obj-$(CONFIG_SERIAL_8250_FSL)		+= 8250_fsl.o
>  obj-$(CONFIG_SERIAL_8250_DW)		+= 8250_dw.o
>  obj-$(CONFIG_SERIAL_8250_EM)		+= 8250_em.o

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy