Re: [PATCH] Input: serio - Add ARC PS/2 driver

[Dmitry Torokhov]

Hi Mischa,

On Tue, Oct 16, 2012 at 05:44:58PM +0200, Mischa Jonker wrote:
> This adds support for the PS/2 block that is used in various ARC FPGA
> platforms.

This looks very nicem just a few comments below.

> 
> Signed-off-by: Mischa Jonker <mischa.jonker@xxxxxxxxxxxx>
> ---
>  drivers/input/serio/Kconfig   |    9 ++
>  drivers/input/serio/Makefile  |    1 +
>  drivers/input/serio/arc_ps2.c |  287 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 297 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/input/serio/arc_ps2.c
> 
> diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
> index 55f2c22..4a4e182 100644
> --- a/drivers/input/serio/Kconfig
> +++ b/drivers/input/serio/Kconfig
> @@ -234,4 +234,13 @@ config SERIO_PS2MULT
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called ps2mult.
>  
> +config SERIO_ARC_PS2
> +	tristate "ARC PS/2 support"
> +	help
> +	  Say Y here if you have an ARC FPGA platform with a PS/2
> +	  controller in it.
> +
> +	  To compile this driver as a module, choose M here; the module
> +	  will be called arc_ps2.
> +
>  endif
> diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
> index dbbe376..4b0c8f8 100644
> --- a/drivers/input/serio/Makefile
> +++ b/drivers/input/serio/Makefile
> @@ -25,3 +25,4 @@ obj-$(CONFIG_SERIO_RAW)		+= serio_raw.o
>  obj-$(CONFIG_SERIO_AMS_DELTA)	+= ams_delta_serio.o
>  obj-$(CONFIG_SERIO_XILINX_XPS_PS2)	+= xilinx_ps2.o
>  obj-$(CONFIG_SERIO_ALTERA_PS2)	+= altera_ps2.o
> +obj-$(CONFIG_SERIO_ARC_PS2)	+= arc_ps2.o
> diff --git a/drivers/input/serio/arc_ps2.c b/drivers/input/serio/arc_ps2.c
> new file mode 100644
> index 0000000..54a24eb
> --- /dev/null
> +++ b/drivers/input/serio/arc_ps2.c
> @@ -0,0 +1,287 @@
> +/*
> + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.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.
> + *
> + * Driver is originally developed by Pavel Sokolov <psokolov@xxxxxxxxxxxx>
> + */
> +
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/input.h>
> +#include <linux/serio.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +
> +#define ARC_PS2_PORTS                   (2)
> +
> +#define ARC_ARC_PS2_ID                  (0x0001f609)
> +
> +#define STAT_TIMEOUT                    (128)
> +
> +#define PS2_STAT_RX_FRM_ERR             (1)
> +#define PS2_STAT_RX_BUF_OVER            (1 << 1)
> +#define PS2_STAT_RX_INT_EN              (1 << 2)
> +#define PS2_STAT_RX_VAL                 (1 << 3)
> +#define PS2_STAT_TX_ISNOT_FUL           (1 << 4)
> +#define PS2_STAT_TX_INT_EN              (1 << 5)
> +
> +struct arc_ps2_port {
> +	unsigned data, status;
> +	struct serio *io;
> +};
> +
> +struct arc_ps2_data {
> +	struct arc_ps2_port port[ARC_PS2_PORTS];
> +	struct resource *iomem_res;
> +	int irq;
> +	unsigned long addr;
> +	unsigned frame_error;
> +	unsigned buf_overflow;
> +	unsigned total_int;
> +};
> +
> +static void arc_ps2_check_rx(struct arc_ps2_data *arc_ps2,
> +			     struct arc_ps2_port *port)
> +{
> +	unsigned flag, status;
> +	unsigned char data;
> +
> +	do {

Normally endless loop is while (1) {} instead of do {} while (1).

> +		status = inl(port->status);
> +		if (!(status & PS2_STAT_RX_VAL))
> +			break;
> +		flag = 0;
> +
> +		arc_ps2->total_int++;
> +		if (status & PS2_STAT_RX_FRM_ERR) {
> +			arc_ps2->frame_error++;
> +			flag |= SERIO_PARITY;
> +		} else if (status & PS2_STAT_RX_BUF_OVER) {
> +			arc_ps2->buf_overflow++;
> +			flag |= SERIO_FRAME;
> +		}
> +		data = inl(port->data) & 0xff;
> +
> +		serio_interrupt(port->io, data, flag);
> +	} while (1);
> +}
> +
> +static irqreturn_t arc_ps2_interrupt(int irq, void *dev)
> +{
> +	struct arc_ps2_data *arc_ps2 = dev;
> +	int i;
> +
> +	for (i = 0; i < ARC_PS2_PORTS; i++)
> +		arc_ps2_check_rx(arc_ps2, &arc_ps2->port[i]);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int arc_ps2_write(struct serio *io, unsigned char val)
> +{
> +	unsigned status;
> +	struct arc_ps2_port *port = io->port_data;
> +	int timeout = STAT_TIMEOUT;
> +
> +	do {
> +		status = inl(port->status);
> +		cpu_relax();
> +		timeout--;
> +	} while (!(status & PS2_STAT_TX_ISNOT_FUL) && timeout);
> +
> +	if (timeout)
> +		outl(val & 0xff, port->data);
> +	else {
> +		pr_err("%s: write timeout\n", __func__);
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
> +static int arc_ps2_open(struct serio *io)
> +{
> +	struct arc_ps2_port *port = io->port_data;
> +	outl(PS2_STAT_RX_INT_EN, port->status);
> +	return 0;
> +}
> +
> +static void arc_ps2_close(struct serio *io)
> +{
> +	struct arc_ps2_port *port = io->port_data;
> +
> +	outl(inl(port->status) & ~PS2_STAT_RX_INT_EN, port->status);
> +}
> +
> +int __devinit arc_ps2_allocate_port(struct arc_ps2_port *port, int index,
> +				    unsigned base)

Static?

> +{
> +	port->io = kzalloc(sizeof(struct serio), GFP_KERNEL);
> +	if (!port->io)
> +		return -1;

Why doesn't it return -ENOMEM directly?

> +
> +	port->io->id.type = SERIO_8042;
> +	port->io->write = arc_ps2_write;
> +	port->io->open = arc_ps2_open;
> +	port->io->close = arc_ps2_close;

I am a fan of temps to avoid chaining of dereferences, so maybe we could
have struct serio *io?

> +	snprintf(port->io->name, sizeof(port->io->name), "ARC PS/2 port%d",
> +		 index);
> +	snprintf(port->io->phys, sizeof(port->io->phys), "arc/serio%d", index);
> +	port->io->port_data = port;
> +
> +	port->data = base + 4 + index * 4;
> +	port->status = base + 4 + ARC_PS2_PORTS * 4 + index * 4;
> +
> +	pr_debug("%s: port%d is allocated (data = 0x%x, status = 0x%x)\n",
> +		 __func__, index, port->data, port->status);
> +

dev_dbg() please.

> +	return 0;
> +}
> +
> +static int __devinit arc_ps2_probe(struct platform_device *pdev)
> +{
> +	struct arc_ps2_data *arc_ps2;
> +	int ret, id, i;
> +
> +	arc_ps2 = kzalloc(sizeof(struct arc_ps2_data), GFP_KERNEL);
> +	if (!arc_ps2) {
> +		pr_err("%s: ERROR: out of memory\n", __func__);

You have [platform] device structure so please use dev_err() here and
elsewhere.

> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	arc_ps2->iomem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!arc_ps2->iomem_res) {
> +		pr_err("%s: ERROR: no IO memory defined\n", __func__);
> +		ret = -ENODEV;
> +		goto out_free;
> +	}
> +
> +	arc_ps2->irq = platform_get_irq_byname(pdev, "arc_ps2_irq");
> +	if (arc_ps2->irq < 0) {
> +		pr_err("%s: ERROR: no IRQ defined\n", __func__);
> +		ret = -ENODEV;
> +		goto out_free;
> +	}
> +
> +	if (!request_mem_region(arc_ps2->iomem_res->start,
> +	    resource_size(arc_ps2->iomem_res), pdev->name)) {
> +		pr_err("%s: ERROR: memory allocation failed cannot get the I/O addr 0x%x\n",
> +		       __func__, (unsigned int)arc_ps2->iomem_res->start);
> +
> +		ret = -EBUSY;
> +		goto out_free;
> +	}
> +
> +	arc_ps2->addr = (unsigned long) ioremap_nocache(arc_ps2->iomem_res->
> +			start, resource_size(arc_ps2->iomem_res));
> +	if (!arc_ps2->addr) {
> +		pr_err("%s: ERROR: memory mapping failed\n", __func__);
> +		ret = -ENOMEM;
> +		goto out_release_region;
> +	}
> +
> +	pr_info("%s: irq = %d, address = 0x%lx, ports = %i\n", __func__,
> +	       arc_ps2->irq, arc_ps2->addr, ARC_PS2_PORTS);
> +
> +	id = inl(arc_ps2->addr);

Hmm, if you did ioremap why are you using IO port operations? Shouldn't
this be ioread32() instead?

> +	if (id != ARC_ARC_PS2_ID) {
> +		pr_err("%s: device id does not match\n", __func__);
> +		ret = ENXIO;
> +		goto out_unmap;
> +	}
> +
> +	platform_set_drvdata(pdev, arc_ps2);
> +
> +	for (i = 0; i < ARC_PS2_PORTS; i++) {
> +		if (arc_ps2_allocate_port(&arc_ps2->port[i], i,
> +					  arc_ps2->addr)) {
> +			ret = -ENOMEM;
> +			goto release;
> +		}
> +		serio_register_port(arc_ps2->port[i].io);
> +	}
> +
> +	ret = request_irq(arc_ps2->irq, arc_ps2_interrupt, 0,
> +			  "arc_ps2", arc_ps2);
> +	if (ret) {
> +		pr_err("%s: Could not allocate IRQ\n", __func__);
> +		goto release;
> +	}
> +
> +	return 0;
> +
> +release:
> +	for (i = 0; i < ARC_PS2_PORTS; i++) {
> +		if (arc_ps2->port[i].io)
> +			serio_unregister_port(arc_ps2->port[i].io);
> +	}
> +out_unmap:
> +	iounmap((void __iomem *) arc_ps2->addr);
> +out_release_region:
> +	release_mem_region(arc_ps2->iomem_res->start,
> +			   resource_size(arc_ps2->iomem_res));
> +out_free:
> +	kfree(arc_ps2);
> +out:
> +	return ret;
> +}
> +
> +static int __devexit arc_ps2_remove(struct platform_device *dev)
> +{
> +	struct arc_ps2_data *arc_ps2;
> +	int i;
> +
> +	arc_ps2 = platform_get_drvdata(dev);
> +	for (i = 0; i < ARC_PS2_PORTS; i++) {
> +		/* turn off any interrupts */
> +		outl(0, arc_ps2->port[i].status);

How do you turn interrupts back on?

> +		serio_unregister_port(arc_ps2->port[i].io);
> +	}
> +
> +	free_irq(arc_ps2->irq, arc_ps2);
> +	iounmap((void __iomem *) arc_ps2->addr);
> +	release_mem_region(arc_ps2->iomem_res->start,
> +			   resource_size(arc_ps2->iomem_res));
> +
> +	pr_debug("%s: interrupt count = %i\n", __func__, arc_ps2->total_int);
> +	pr_debug("%s: frame error count = %i\n", __func__,
> +	       arc_ps2->frame_error);
> +	pr_debug("%s: buffer overflow count = %i\n", __func__,
> +	       arc_ps2->buf_overflow);
> +
> +	kfree(arc_ps2);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver arc_ps2_driver = {
> +	.driver = {
> +		   .name = "arc_ps2",
> +		   .owner = THIS_MODULE,
> +		   },
> +	.probe = arc_ps2_probe,
> +	.remove = __devexit_p(arc_ps2_remove),
> +};
> +
> +static int __init arc_ps2_init(void)
> +{
> +	return platform_driver_register(&arc_ps2_driver);
> +}
> +
> +static void __exit arc_ps2_exit(void)
> +{
> +	platform_driver_unregister(&arc_ps2_driver);
> +}
> +
> +/* --------------------------------------------------------------------- */
> +module_init(arc_ps2_init);
> +module_exit(arc_ps2_exit);

The last 2 functions can be replaced with:
module_platform_driver(arc_ps2_driver);

> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Pavel Sokolov <psokolov@xxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("ARC PS/2 Driver");
> -- 
> 1.7.0.4
> 

Thanks.

-- 
Dmitry
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/