From: wg@grandegger•com (Wolfgang Grandegger)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RESEND 0/6 v10] gpio: Add block GPIO
Date: Mon, 17 Dec 2012 20:47:31 +0100 [thread overview]
Message-ID: <50CF76D3.9030708@grandegger.com> (raw)
In-Reply-To: <50CF5E45.5030104@antcom.de>
On 12/17/2012 07:02 PM, Roland Stigge wrote:
> On 12/17/2012 06:37 PM, Wolfgang Grandegger wrote:
>> /* Do synchronous data output with a single write access */
>> __raw_writel(~mask, pio + PIO_OWDR);
>> __raw_writel(mask, pio + PIO_OWER);
>> __raw_writel(val, pio + PIO_ODSR);
>>
>> For caching we would need a storage. Not sure if it's worth compared to
>> a context switch into the kernel.
>
> Block GPIO is not only for you in userspace. ;-) You can also implement
> efficient n-bit bus I/O in kernel drivers, n-bit-banging. :-) So not
> always context switches involved.
OK, what do you think about the following untested patch:
>From b44cad16cbbca84715dffd4cb5268497216add25 Mon Sep 17 00:00:00 2001
From: Wolfgang Grandegger <wg@grandegger•com>
Date: Mon, 3 Dec 2012 08:31:55 +0100
Subject: [PATCH 1/2] gpio: add GPIO block callback functions for AT91
Signed-off-by: Wolfgang Grandegger <wg@grandegger•com>
---
arch/arm/mach-at91/gpio.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/arch/arm/mach-at91/gpio.c b/arch/arm/mach-at91/gpio.c
index be42cf0..cf6bd45 100644
--- a/arch/arm/mach-at91/gpio.c
+++ b/arch/arm/mach-at91/gpio.c
@@ -42,13 +42,16 @@ struct at91_gpio_chip {
void __iomem *regbase; /* PIO bank virtual address */
struct clk *clock; /* associated clock */
struct irq_domain *domain; /* associated irq domain */
+ unsigned long mask_shadow; /* synchronous data output */
};
#define to_at91_gpio_chip(c) container_of(c, struct at91_gpio_chip, chip)
static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip);
static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val);
+static void at91_gpiolib_set_block(struct gpio_chip *chip, unsigned long mask, unsigned long val);
static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset);
+static unsigned long at91_gpiolib_get_block(struct gpio_chip *chip, unsigned long mask);
static int at91_gpiolib_direction_output(struct gpio_chip *chip,
unsigned offset, int val);
static int at91_gpiolib_direction_input(struct gpio_chip *chip,
@@ -62,7 +65,9 @@ static int at91_gpiolib_to_irq(struct gpio_chip *chip, unsigned offset);
.direction_input = at91_gpiolib_direction_input, \
.direction_output = at91_gpiolib_direction_output, \
.get = at91_gpiolib_get, \
+ .get_block = at91_gpiolib_get_block, \
.set = at91_gpiolib_set, \
+ .set_block = at91_gpiolib_set_block, \
.dbg_show = at91_gpiolib_dbg_show, \
.to_irq = at91_gpiolib_to_irq, \
.ngpio = nr_gpio, \
@@ -896,6 +901,16 @@ static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset)
return (pdsr & mask) != 0;
}
+static unsigned long at91_gpiolib_get_block(struct gpio_chip *chip, unsigned long mask)
+{
+ struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
+ void __iomem *pio = at91_gpio->regbase;
+ u32 pdsr;
+
+ pdsr = __raw_readl(pio + PIO_PDSR);
+ return pdsr & mask;
+}
+
static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val)
{
struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
@@ -905,6 +920,20 @@ static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val)
__raw_writel(mask, pio + (val ? PIO_SODR : PIO_CODR));
}
+static void at91_gpiolib_set_block(struct gpio_chip *chip, unsigned long mask, unsigned long val)
+{
+ struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
+ void __iomem *pio = at91_gpio->regbase;
+
+ /* Do synchronous data output with a single write access */
+ if (mask != at91_gpio->mask_shadow) {
+ at91_gpio->mask_shadow = mask;
+ __raw_writel(~mask, pio + PIO_OWDR);
+ __raw_writel(mask, pio + PIO_OWER);
+ }
+ __raw_writel(val, pio + PIO_ODSR);
+}
+
static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
int i;
--
1.7.9.5
next prev parent reply other threads:[~2012-12-17 19:47 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-14 14:26 [PATCH RESEND 0/6 v10] gpio: Add block GPIO Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 1/6 v10] gpio: Add a block GPIO API to gpiolib Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 2/6 v10] gpio: Add sysfs support to block GPIO API Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 3/6 v10] gpio: Add userland device interface to block GPIO Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 4/6 v10] gpiolib: Fix default attributes for class Roland Stigge
2012-12-14 14:26 ` [PATCH RESEND 5/6 v10] gpio: Add device tree support to block GPIO API Roland Stigge
2012-12-17 15:51 ` Mark Rutland
2012-12-18 14:30 ` Roland Stigge
2012-12-18 16:35 ` Mark Rutland
2012-12-14 14:26 ` [PATCH RESEND 6/6 v10] gpio: Add block gpio to several gpio drivers Roland Stigge
2012-12-14 17:58 ` [PATCH RESEND 0/6 v10] gpio: Add block GPIO Wolfgang Grandegger
2012-12-14 23:49 ` Roland Stigge
2012-12-15 10:51 ` Russell King - ARM Linux
2012-12-17 11:37 ` Wolfgang Grandegger
2012-12-17 11:51 ` Wolfgang Grandegger
2012-12-17 12:10 ` Russell King - ARM Linux
2012-12-17 14:57 ` Wolfgang Grandegger
2012-12-17 13:32 ` Roland Stigge
2012-12-17 13:51 ` Roland Stigge
2012-12-17 16:28 ` Wolfgang Grandegger
2012-12-17 17:15 ` Roland Stigge
2012-12-17 17:37 ` Wolfgang Grandegger
2012-12-17 18:02 ` Roland Stigge
2012-12-17 19:47 ` Wolfgang Grandegger [this message]
2012-12-17 21:33 ` Roland Stigge
2012-12-18 6:51 ` Wolfgang Grandegger
2012-12-18 5:55 ` Jean-Christophe PLAGNIOL-VILLARD
2012-12-18 6:58 ` Wolfgang Grandegger
2012-12-18 7:54 ` Jean-Christophe PLAGNIOL-VILLARD
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