[PATCH] AMD Geode CS553X GPIO driver
David Brownell
david-b at pacbell.net
Fri Dec 26 13:24:07 EST 2008
On Wednesday 24 December 2008, Alessandro Zummo wrote:
>
> A GPIO driver for the AMD Geode CS5535/5536 Companion Devices.
Great -- embedded x86 looking more like embedded rest-of-Linux! ;)
> It uses the gpio framework and the gpio api as defined in
> arch/x86/kernel/geode_32.c
Eventually I'd hope to see those geode_32.c calls just vanish.
In fact, the "normal" way to package these GPIOs would be to
always provide them through the standard API, in arch/... code,
with no Kconfig option. Any reason you shouldn't do that in
this patch?
> Patch is against 2.6.28-rc9.
>
> Signed-off-by: Alessandro Zummo <a.zummo at towertech.it>
>
>
> ---
> arch/x86/include/asm/geode.h | 18 ++++
> drivers/gpio/Kconfig | 14 +++
> drivers/gpio/Makefile | 1
> drivers/gpio/cs553x-gpio.c | 172 +++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 205 insertions(+)
>
> --- linux-tuxrouter-2.6.28-rc9.orig/drivers/gpio/Kconfig 2008-12-24 23:34:02.000000000 +0100
> +++ linux-tuxrouter-2.6.28-rc9/drivers/gpio/Kconfig 2008-12-24 23:34:44.000000000 +0100
> @@ -175,4 +175,18 @@ config GPIO_MCP23S08
> SPI driver for Microchip MCP23S08 I/O expander. This provides
> a GPIO interface supporting inputs and outputs.
>
> +comment "Other GPIO expanders:"
This counts as "memory mapped" I'd say. Doesn't need
a new category, even if this does need to live outside
the relevant arch/... files.
> +
> +config GPIO_CS553X
> + tristate "AMD CS5535/CS5536 Geode Companion Devices"
> + depends on MGEODE_LX && !CS5535_GPIO
What's this CS5535_GPIO stuff? And why should it affect
whether this can be configured? (It's not in mainline...)
> + help
> + Say yes here to provide support for the 28 GPIO pins on
> + the AMD CS5535 and CS5536 Geode Companion Devices.
> +
> + Your board setup code will have to declare an appropriate
> + platform device for this driver to work.
> +
> + If unsure, say N.
> +
> endif
> --- linux-tuxrouter-2.6.28-rc9.orig/drivers/gpio/Makefile 2008-12-24 23:34:02.000000000 +0100
> +++ linux-tuxrouter-2.6.28-rc9/drivers/gpio/Makefile 2008-12-24 23:34:44.000000000 +0100
> @@ -4,6 +4,7 @@ ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
>
> obj-$(CONFIG_GPIOLIB) += gpiolib.o
>
> +obj-$(CONFIG_GPIO_CS553X) += cs553x-gpio.o
> obj-$(CONFIG_GPIO_MAX7301) += max7301.o
> obj-$(CONFIG_GPIO_MAX732X) += max732x.o
> obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o
> --- linux-tuxrouter-2.6.28-rc9.orig/arch/x86/include/asm/geode.h 2008-12-24 23:34:02.000000000 +0100
> +++ linux-tuxrouter-2.6.28-rc9/arch/x86/include/asm/geode.h 2008-12-24 23:34:44.000000000 +0100
> @@ -12,6 +12,7 @@
>
> #include <asm/processor.h>
> #include <linux/io.h>
> +#include <linux/platform_device.h>
>
> /* Generic southbridge functions */
>
> @@ -165,6 +166,23 @@ static inline void geode_gpio_event_pme(
> geode_gpio_setup_event(gpio, pair, 1);
> }
>
> +struct cs553x_gpio_platform_data {
> +
> + unsigned gpio_base; /* number of the first GPIO */
> +
> + resource_size_t io_base;
Platform devices should use platform_get_resource() and
friends instead of passing resources through platform data.
> +
> + void *context; /* param to setup/teardown */
> +
> + int (*setup)(struct platform_device *pdev,
> + unsigned base, unsigned ngpio,
> + void *context);
> +
> + int (*teardown)(struct platform_device *pdev,
> + unsigned base, unsigned ngpio,
> + void *context);
> +};
> +
> /* Specific geode tests */
>
> static inline int is_geode_gx(void)
... other than those points, this seems like a simple and
straightforward GPIO driver. Typical of what arch/* holds
in such cases. ;)
- Dave
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-tuxrouter-2.6.28-rc9/drivers/gpio/cs553x-gpio.c 2008-12-24 23:35:41.000000000 +0100
> @@ -0,0 +1,172 @@
> +/*
> + * AMD CS5535/CS5536 Geode Companion Devices GPIO driver
> + *
> + * Copyright (C) 2008 Tower Technologies
> + * Written by Alessandro Zummo <a.zummo at towertech.it>
> + *
> + * 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/module.h>
> +#include <linux/errno.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/ioport.h>
> +#include <linux/gpio.h>
> +#include <linux/platform_device.h>
> +
> +#include <asm/geode.h>
> +
> +#define DRIVER_NAME "cs553x-gpio"
> +#define DRIVER_VERSION "1.0"
> +
> +static void cs553x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> +{
> + if (value)
> + geode_gpio_set(geode_gpio(offset), GPIO_OUTPUT_VAL);
> + else
> + geode_gpio_clear(geode_gpio(offset), GPIO_OUTPUT_VAL);
> +}
> +
> +static int cs553x_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> + return geode_gpio_isset(geode_gpio(offset), GPIO_READ_BACK);
> +}
> +
> +static int cs553x_direction_input(struct gpio_chip *chip, unsigned offset)
> +{
> + geode_gpio_clear(geode_gpio(offset), GPIO_OUTPUT_ENABLE);
> + geode_gpio_set(geode_gpio(offset), GPIO_INPUT_ENABLE);
> +
> + return 0;
> +}
> +
> +static int cs553x_direction_output(struct gpio_chip *chip, unsigned offset,
> + int value)
> +{
> + cs553x_gpio_set(chip, offset, value);
> +
> + geode_gpio_set(geode_gpio(offset), GPIO_OUTPUT_ENABLE);
> + geode_gpio_clear(geode_gpio(offset), GPIO_INPUT_ENABLE);
> +
> + return 0;
> +}
> +
> +static struct gpio_chip cs553x = {
> + .owner = THIS_MODULE,
> + .label = DRIVER_NAME,
> + .ngpio = 28,
> +
> + .get = cs553x_gpio_get,
> + .set = cs553x_gpio_set,
> +
> + .direction_input = cs553x_direction_input,
> + .direction_output = cs553x_direction_output,
> +};
> +
> +
> +static int __init cs553x_gpio_probe(struct platform_device *pdev)
> +{
> + int rc;
> + struct cs553x_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> + if (pdata == NULL) {
> + dev_err(&pdev->dev, "missing CS553X platform data\n");
> + return -ENODEV;
> + }
> +
> + if (!pdata->io_base) {
> + dev_err(&pdev->dev, "platform data has no GPIO base region\n");
> + return -ENODEV;
> + }
> +
> + if (!request_region(pdata->io_base, LBAR_GPIO_SIZE, DRIVER_NAME)) {
> + dev_err(&pdev->dev, "cannot allocate I/O region at %x\n",
> + pdata->io_base);
> + return -ENODEV;
> + }
> +
> + cs553x.dev = &pdev->dev;
> + cs553x.base = pdata->gpio_base;
> +
> + rc = gpiochip_add(&cs553x);
> + if (rc < 0) {
> + dev_err(&pdev->dev, "cannot add GPIO\n");
> + goto fail_release;
> + }
> +
> + dev_info(&pdev->dev, "registered at 0x%x, GPIO base %d\n",
> + pdata->io_base, cs553x.base);
> +
> + if (pdata->setup) {
> + rc = pdata->setup(pdev, cs553x.base,
> + cs553x.ngpio, pdata->context);
> +
> + if (rc < 0) {
> + dev_err(&pdev->dev, "setup failed, %d\n", rc);
> + goto fail_remove;
> + }
> + }
> +
> + return 0;
> +
> +fail_remove:
> + gpiochip_remove(&cs553x);
> +
> +fail_release:
> + release_region(pdata->io_base, LBAR_GPIO_SIZE);
> +
> + return rc;
> +}
> +
> +static int __exit cs553x_gpio_remove(struct platform_device *pdev)
> +{
> + struct cs553x_gpio_platform_data *pdata = pdev->dev.platform_data;
> +
> + if (pdata->teardown) {
> + int rc = pdata->teardown(pdev, cs553x.base,
> + cs553x.ngpio, pdata->context);
> + if (rc < 0) {
> + dev_err(&pdev->dev, "teardown failed, %d\n", rc);
> + return rc;
> + }
> + }
> +
> + gpiochip_remove(&cs553x);
> + release_region(pdata->io_base, LBAR_GPIO_SIZE);
> +
> + return 0;
> +}
> +
> +static struct platform_driver cs553x_gpio_driver = {
> + .driver = {
> + .name = DRIVER_NAME,
> + .owner = THIS_MODULE,
> + },
> + .remove = __exit_p(cs553x_gpio_remove),
> +};
> +
> +static int __init cs553x_gpio_init(void)
> +{
> + if (!is_geode())
> + return -ENODEV;
> +
> + return platform_driver_probe(&cs553x_gpio_driver, cs553x_gpio_probe);
> +}
> +
> +static void __exit cs553x_gpio_exit(void)
> +{
> + platform_driver_unregister(&cs553x_gpio_driver);
> +}
> +
> +module_init(cs553x_gpio_init);
> +module_exit(cs553x_gpio_exit);
> +
> +
> +MODULE_AUTHOR("Alessandro Zummo <a.zummo at towertech.it>");
> +MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO driver");
> +MODULE_LICENSE("GPL");
> +MODULE_VERSION(DRIVER_VERSION);
> +MODULE_ALIAS("platform:cs553x-gpio");
>
> --
>
> Best regards,
>
> Alessandro Zummo,
> Tower Technologies - Torino, Italy
>
> http://www.towertech.it
>
>
More information about the Linux-geode
mailing list