On 12/18/2012 06:55 AM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 20:47 Mon 17 Dec , Wolfgang Grandegger wrote:
>> 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 <w...@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 <w...@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);
>> +}
> this driver is only for old at91 platfrom if you touch at91 you need to update
> the pinctrl too
Well, the patch is for the hardware I have at hand and I can test. There
are many other GPIO hardware interfaces which could be enhanced with
block gpio. Roland only did it for the interfaces in driver/gpio. Also,
I think, an ACK for this patch series would be nice before we continue.
Wolfgang.
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