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Date: Tue, 5 Jul 2011 10:40:59 +0530
From: Sekhar Nori <nsekhar@...com>
To: <linux-kernel@...r.kernel.org>
CC: Kevin Hilman <khilman@...com>,
Grant Likely <grant.likely@...retlab.ca>,
Cyril Chemparathy <cyril@...com>,
<linux-arm-kernel@...ts.infradead.org>,
<davinci-linux-open-source@...ux.davincidsp.com>,
Sekhar Nori <nsekhar@...com>
Subject: [RFC/RFT 1/2] gpio/basic_mmio: add support for enable register
Some GPIO controllers have an enable register
which needs to be written to before a GPIO
can be used.
Add support for enabling the GPIO. At this
time inverted logic for enabling the GPIO
is not supported. This can be done by adding
a disable register as and when a controller
with this comes along.
Signed-off-by: Sekhar Nori <nsekhar@...com>
---
drivers/gpio/gpio-ep93xx.c | 2 +-
drivers/gpio/gpio-generic.c | 45 ++++++++++++++++++++++++++++++++++++++-
drivers/gpio/gpio-mxc.c | 2 +-
drivers/gpio/gpio-mxs.c | 2 +-
include/linux/basic_mmio_gpio.h | 5 ++++
5 files changed, 52 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpio-ep93xx.c b/drivers/gpio/gpio-ep93xx.c
index 3bfd341..8ed498a 100644
--- a/drivers/gpio/gpio-ep93xx.c
+++ b/drivers/gpio/gpio-ep93xx.c
@@ -314,7 +314,7 @@ static int ep93xx_gpio_add_bank(struct bgpio_chip *bgc, struct device *dev,
void __iomem *dir = mmio_base + bank->dir;
int err;
- err = bgpio_init(bgc, dev, 1, data, NULL, NULL, dir, NULL, false);
+ err = bgpio_init(bgc, dev, 1, data, NULL, NULL, dir, NULL, NULL, false);
if (err)
return err;
diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index 231714d..cf7d596 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -247,6 +247,34 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
return 0;
}
+static int bgpio_request(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->en |= bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_en, bgc->en);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+
+ return 0;
+}
+
+static void bgpio_free(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&bgc->lock, flags);
+
+ bgc->en &= ~bgc->pin2mask(bgc, gpio);
+ bgc->write_reg(bgc->reg_en, bgc->en);
+
+ spin_unlock_irqrestore(&bgc->lock, flags);
+}
+
static int bgpio_setup_accessors(struct device *dev,
struct bgpio_chip *bgc,
bool be)
@@ -302,6 +330,10 @@ static int bgpio_setup_accessors(struct device *dev,
* indicates the GPIO is an output.
* - an input direction register (named "dirin") where a 1 bit indicates
* the GPIO is an input.
+ *
+ * To enable and disable a GPIO at the time of requesting it there is a
+ * a simple enable register supported where a 1 bit indicates that the GPIO
+ * is enabled.
*/
static int bgpio_setup_io(struct bgpio_chip *bgc,
void __iomem *dat,
@@ -369,6 +401,7 @@ int __devinit bgpio_init(struct bgpio_chip *bgc,
void __iomem *clr,
void __iomem *dirout,
void __iomem *dirin,
+ void __iomem *en,
bool big_endian)
{
int ret;
@@ -398,6 +431,11 @@ int __devinit bgpio_init(struct bgpio_chip *bgc,
if (ret)
return ret;
+ if (en) {
+ bgc->gc.request = bgpio_request;
+ bgc->gc.free = bgpio_free;
+ }
+
bgc->data = bgc->read_reg(bgc->reg_dat);
return ret;
@@ -453,6 +491,7 @@ static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
void __iomem *clr;
void __iomem *dirout;
void __iomem *dirin;
+ void __iomem *en;
unsigned long sz;
bool be;
int err;
@@ -485,13 +524,17 @@ static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
if (err)
return err;
+ en = bgpio_map(pdev, "en", sz, &err);
+ if (err)
+ return err;
+
be = !strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be");
bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
if (!bgc)
return -ENOMEM;
- err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, be);
+ err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, en, be);
if (err)
return err;
diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
index 2f6a81b..5ce98c6 100644
--- a/drivers/gpio/gpio-mxc.c
+++ b/drivers/gpio/gpio-mxc.c
@@ -300,7 +300,7 @@ static int __devinit mxc_gpio_probe(struct platform_device *pdev)
err = bgpio_init(&port->bgc, &pdev->dev, 4,
port->base + GPIO_PSR,
port->base + GPIO_DR, NULL,
- port->base + GPIO_GDIR, NULL, false);
+ port->base + GPIO_GDIR, NULL, NULL, false);
if (err)
goto out_iounmap;
diff --git a/drivers/gpio/gpio-mxs.c b/drivers/gpio/gpio-mxs.c
index d8cafba..f3b78bf 100644
--- a/drivers/gpio/gpio-mxs.c
+++ b/drivers/gpio/gpio-mxs.c
@@ -241,7 +241,7 @@ static int __devinit mxs_gpio_probe(struct platform_device *pdev)
err = bgpio_init(&port->bgc, &pdev->dev, 4,
port->base + PINCTRL_DIN(port->id),
port->base + PINCTRL_DOUT(port->id), NULL,
- port->base + PINCTRL_DOE(port->id), NULL, false);
+ port->base + PINCTRL_DOE(port->id), NULL, NULL, false);
if (err)
goto out_iounmap;
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index 98999cf..fc2e1cc 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -35,6 +35,7 @@ struct bgpio_chip {
void __iomem *reg_set;
void __iomem *reg_clr;
void __iomem *reg_dir;
+ void __iomem *reg_en;
/* Number of bits (GPIOs): <register width> * 8. */
int bits;
@@ -56,6 +57,9 @@ struct bgpio_chip {
/* Shadowed direction registers to clear/set direction safely. */
unsigned long dir;
+
+ /* Shadowed enable register to enable/disable safely. */
+ unsigned long en;
};
static inline struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
@@ -72,6 +76,7 @@ int __devinit bgpio_init(struct bgpio_chip *bgc,
void __iomem *clr,
void __iomem *dirout,
void __iomem *dirin,
+ void __iomem *en,
bool big_endian);
#endif /* __BASIC_MMIO_GPIO_H */
--
1.7.3.2
--
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