Re: [PATCH] gpio: New driver for the Intel 82801 (ICH) GPIO pins

From: Anton Vorontsov
Date: Tue Apr 19 2011 - 16:30:45 EST

On Tue, Apr 19, 2011 at 06:08:29PM +0100, Alan Cox wrote:
> > How about exporting some bus/device-type neutral probe function, like
> > we do in drivers/ata/pata_platform.c ?
>
> Not sure you want to be using resources as the basic currency, nor do you
> want your generic code doing the request_region stuff. That was a nasty
> mistake we made in the IDE code.
>
> Maybe the platform code should do that bit, but the generic stuff not - in
> the PCI case the caller will have done pci_request_* itself and chances
> are several of the resources are the same pci device resource and
> different offsets so doing request_resource on them will blow up.

Oh, right. How about this:

int __devinit bgpio_probe(struct device *dev,
unsigned long sz,
void __iomem *dat,
void __iomem *set,
void __iomem *clr,
void __iomem *dirout,
void __iomem *dirin,
bool big_endian);

I.e. PCI driver can now map the whole area with a single ioremap(),
and then call bgpio_probe(), which will provide accessors and
common MMIO GPIO registration stuff.

Not-yet-signed-off-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
---
drivers/gpio/Kconfig | 6 +
drivers/gpio/Makefile | 1 +
drivers/gpio/basic_mmio_gpio.c | 241 ++++++++++++++++++++++++---------------
include/linux/basic_mmio_gpio.h | 15 +++
4 files changed, 171 insertions(+), 92 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 664660e..88dd650 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -70,8 +70,14 @@ config GPIO_MAX730X

comment "Memory mapped GPIO expanders:"

+config GPIO_BASIC_MMIO_CORE
+ tristate
+ help
+ Provides core functionality for basic memory-mapped GPIO controllers.
+
config GPIO_BASIC_MMIO
tristate "Basic memory-mapped GPIO controllers support"
+ select GPIO_BASIC_MMIO_CORE
help
Say yes here to support basic memory-mapped GPIO controllers.

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 3351cf8..1abf916 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_GPIOLIB) += gpiolib.o

obj-$(CONFIG_GPIO_ADP5520) += adp5520-gpio.o
obj-$(CONFIG_GPIO_ADP5588) += adp5588-gpio.o
+obj-$(CONFIG_GPIO_BASIC_MMIO_CORE) += basic_mmio_gpio.o
obj-$(CONFIG_GPIO_BASIC_MMIO) += basic_mmio_gpio.o
obj-$(CONFIG_GPIO_LANGWELL) += langwell_gpio.o
obj-$(CONFIG_GPIO_MAX730X) += max730x.o
diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index b2ec45f..947734a 100644
--- a/drivers/gpio/basic_mmio_gpio.c
+++ b/drivers/gpio/basic_mmio_gpio.c
@@ -284,20 +284,10 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
return 0;
}

-static void __iomem *bgpio_request_and_map(struct device *dev,
- struct resource *res)
+static int bgpio_setup_accessors(struct device *dev,
+ struct bgpio_chip *bgc,
+ bool be)
{
- if (!devm_request_mem_region(dev, res->start, resource_size(res),
- res->name ?: "mmio_gpio"))
- return NULL;
-
- return devm_ioremap(dev, res->start, resource_size(res));
-}
-
-static int bgpio_setup_accessors(struct platform_device *pdev,
- struct bgpio_chip *bgc)
-{
- const struct platform_device_id *platid = platform_get_device_id(pdev);

switch (bgc->bits) {
case 8:
@@ -319,13 +309,11 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
break;
#endif /* BITS_PER_LONG >= 64 */
default:
- dev_err(&pdev->dev, "unsupported data width %u bits\n",
- bgc->bits);
+ dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
return -EINVAL;
}

- bgc->pin2mask = strcmp(platid->name, "basic-mmio-gpio-be") ?
- bgpio_pin2mask : bgpio_pin2mask_be;
+ bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;

return 0;
}
@@ -352,51 +340,22 @@ static int bgpio_setup_accessors(struct platform_device *pdev,
* - an input direction register (named "dirin") where a 1 bit indicates
* the GPIO is an input.
*/
-static int bgpio_setup_io(struct platform_device *pdev,
- struct bgpio_chip *bgc)
+static int bgpio_setup_io(struct bgpio_chip *bgc,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr)
{
- struct resource *res_set;
- struct resource *res_clr;
- struct resource *res_dat;
- resource_size_t dat_sz;
-
- res_dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
- if (!res_dat)
- return -EINVAL;
-
- dat_sz = resource_size(res_dat);
- if (!is_power_of_2(dat_sz))
- return -EINVAL;
-
- bgc->bits = dat_sz * 8;
- if (bgc->bits > BITS_PER_LONG)
- return -EINVAL;

- bgc->reg_dat = bgpio_request_and_map(&pdev->dev, res_dat);
+ bgc->reg_dat = dat;
if (!bgc->reg_dat)
- return -ENOMEM;
-
- res_set = platform_get_resource_byname(pdev, IORESOURCE_MEM, "set");
- res_clr = platform_get_resource_byname(pdev, IORESOURCE_MEM, "clr");
- if (res_set && res_clr) {
- if (resource_size(res_set) != resource_size(res_clr) ||
- resource_size(res_set) != resource_size(res_dat))
- return -EINVAL;
-
- bgc->reg_set = bgpio_request_and_map(&pdev->dev, res_set);
- bgc->reg_clr = bgpio_request_and_map(&pdev->dev, res_clr);
- if (!bgc->reg_set || !bgc->reg_clr)
- return -ENOMEM;
+ return -EINVAL;

+ if (set && clr) {
+ bgc->reg_set = set;
+ bgc->reg_clr = clr;
bgc->gc.set = bgpio_set_with_clear;
- } else if (res_set && !res_clr) {
- if (resource_size(res_set) != resource_size(res_dat))
- return -EINVAL;
-
- bgc->reg_set = bgpio_request_and_map(&pdev->dev, res_set);
- if (!bgc->reg_set)
- return -ENOMEM;
-
+ } else if (set && !clr) {
+ bgc->reg_set = set;
bgc->gc.set = bgpio_set_set;
} else {
bgc->gc.set = bgpio_set;
@@ -407,27 +366,18 @@ static int bgpio_setup_io(struct platform_device *pdev,
return 0;
}

-static int bgpio_setup_direction(struct platform_device *pdev,
- struct bgpio_chip *bgc)
+static int bgpio_setup_direction(struct bgpio_chip *bgc,
+ void __iomem *dirout,
+ void __iomem *dirin)
{
- struct resource *res_dirout;
- struct resource *res_dirin;
-
- res_dirout = platform_get_resource_byname(pdev, IORESOURCE_MEM,
- "dirout");
- res_dirin = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dirin");
- if (res_dirout && res_dirin) {
+ if (dirout && dirin) {
return -EINVAL;
- } else if (res_dirout) {
- bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirout);
- if (!bgc->reg_dir)
- return -ENOMEM;
+ } else if (dirout) {
+ bgc->reg_dir = dirout;
bgc->gc.direction_output = bgpio_dir_out;
bgc->gc.direction_input = bgpio_dir_in;
- } else if (res_dirin) {
- bgc->reg_dir = bgpio_request_and_map(&pdev->dev, res_dirin);
- if (!bgc->reg_dir)
- return -ENOMEM;
+ } else if (dirin) {
+ bgc->reg_dir = dirin;
bgc->gc.direction_output = bgpio_dir_out_inv;
bgc->gc.direction_input = bgpio_dir_in_inv;
} else {
@@ -438,9 +388,23 @@ static int bgpio_setup_direction(struct platform_device *pdev,
return 0;
}

-static int __devinit bgpio_probe(struct platform_device *pdev)
+int __devexit bgpio_remove(struct device *dev)
+{
+ struct bgpio_chip *bgc = dev_get_drvdata(dev);
+
+ return gpiochip_remove(&bgc->gc);
+}
+EXPORT_SYMBOL_GPL(bgpio_remove);
+
+int __devinit bgpio_probe(struct device *dev,
+ unsigned long sz,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr,
+ void __iomem *dirout,
+ void __iomem *dirin,
+ bool big_endian)
{
- struct device *dev = &pdev->dev;
struct bgpio_pdata *pdata = dev_get_platdata(dev);
struct bgpio_chip *bgc;
int ret;
@@ -450,9 +414,16 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
if (!bgc)
return -ENOMEM;

- ret = bgpio_setup_io(pdev, bgc);
- if (ret)
- return ret;
+ if (!is_power_of_2(sz))
+ return -EINVAL;
+
+ bgc->bits = sz * 8;
+ if (bgc->bits > BITS_PER_LONG)
+ return -EINVAL;
+
+ spin_lock_init(&bgc->lock);
+ bgc->gc.dev = dev;
+ bgc->gc.label = dev_name(dev);

ngpio = bgc->bits;
if (pdata) {
@@ -463,22 +434,23 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
bgc->gc.base = -1;
}

- ret = bgpio_setup_accessors(pdev, bgc);
+ bgc->gc.ngpio = ngpio;
+
+ ret = bgpio_setup_io(bgc, dat, set, clr);
if (ret)
return ret;

- spin_lock_init(&bgc->lock);
- ret = bgpio_setup_direction(pdev, bgc);
+ ret = bgpio_setup_accessors(dev, bgc, big_endian);
if (ret)
return ret;

- bgc->data = bgc->read_reg(bgc->reg_dat);
+ ret = bgpio_setup_direction(bgc, dirout, dirin);
+ if (ret)
+ return ret;

- bgc->gc.ngpio = ngpio;
- bgc->gc.dev = dev;
- bgc->gc.label = dev_name(dev);
+ bgc->data = bgc->read_reg(bgc->reg_dat);

- platform_set_drvdata(pdev, bgc);
+ dev_set_drvdata(dev, bgc);

ret = gpiochip_add(&bgc->gc);
if (ret)
@@ -486,12 +458,95 @@ static int __devinit bgpio_probe(struct platform_device *pdev)

return ret;
}
+EXPORT_SYMBOL_GPL(bgpio_probe);

-static int __devexit bgpio_remove(struct platform_device *pdev)
+#ifdef CONFIG_GPIO_BASIC_MMIO
+
+static void __iomem *bgpio_map(struct platform_device *pdev,
+ const char *name,
+ resource_size_t sane_sz,
+ int *err)
{
- struct bgpio_chip *bgc = platform_get_drvdata(pdev);
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ resource_size_t start;
+ resource_size_t sz;
+ void __iomem *ret;

- return gpiochip_remove(&bgc->gc);
+ *err = 0;
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
+ if (!r)
+ return NULL;
+
+ sz = resource_size(r);
+ if (sz != sane_sz) {
+ *err = -EINVAL;
+ return NULL;
+ }
+
+ start = r->start;
+ if (!devm_request_mem_region(dev, start, sz, r->name)) {
+ *err = -EBUSY;
+ return NULL;
+ }
+
+ ret = devm_ioremap(dev, start, sz);
+ if (!ret) {
+ *err = -ENOMEM;
+ return NULL;
+ }
+
+ return ret;
+}
+
+static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *r;
+ void __iomem *dat;
+ void __iomem *set;
+ void __iomem *clr;
+ void __iomem *dirout;
+ void __iomem *dirin;
+ unsigned long sz;
+ bool be;
+ int err;
+
+ r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
+ if (!r)
+ return -EINVAL;
+
+ sz = resource_size(r);
+
+ dat = bgpio_map(pdev, "dat", sz, &err);
+ if (!dat)
+ return err ? err : -EINVAL;
+
+ set = bgpio_map(pdev, "set", sz, &err);
+ if (err)
+ return err;
+
+ clr = bgpio_map(pdev, "clr", sz, &err);
+ if (err)
+ return err;
+
+ dirout = bgpio_map(pdev, "dirout", sz, &err);
+ if (err)
+ return err;
+
+ dirin = bgpio_map(pdev, "dirin", sz, &err);
+ if (err)
+ return err;
+
+ be = !strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be");
+
+ return bgpio_probe(dev, sz, dat, set, clr, dirout, dirin, be);
+}
+
+static int __devexit bgpio_pdev_remove(struct platform_device *pdev)
+{
+ return bgpio_remove(&pdev->dev);
}

static const struct platform_device_id bgpio_id_table[] = {
@@ -506,8 +561,8 @@ static struct platform_driver bgpio_driver = {
.name = "basic-mmio-gpio",
},
.id_table = bgpio_id_table,
- .probe = bgpio_probe,
- .remove = __devexit_p(bgpio_remove),
+ .probe = bgpio_pdev_probe,
+ .remove = __devexit_p(bgpio_pdev_remove),
};

static int __init bgpio_init(void)
@@ -522,6 +577,8 @@ static void __exit bgpio_exit(void)
}
module_exit(bgpio_exit);

+#endif /* CONFIG_GPIO_BASIC_MMIO */
+
MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@xxxxxxxxx>");
MODULE_LICENSE("GPL");
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index f23ec73..f3a27e4 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -13,9 +13,24 @@
#ifndef __BASIC_MMIO_GPIO_H
#define __BASIC_MMIO_GPIO_H

+#include <linux/types.h>
+#include <linux/compiler.h>
+
struct bgpio_pdata {
int base;
int ngpio;
};

+struct device;
+
+int __devexit bgpio_remove(struct device *dev);
+int __devinit bgpio_probe(struct device *dev,
+ unsigned long sz,
+ void __iomem *dat,
+ void __iomem *set,
+ void __iomem *clr,
+ void __iomem *dirout,
+ void __iomem *dirin,
+ bool big_endian);
+
#endif /* __BASIC_MMIO_GPIO_H */
--
1.7.4.1

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