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Message-Id: <201111172134.31591.rjw@sisk.pl>
Date: Thu, 17 Nov 2011 21:34:31 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Viresh Kumar <viresh.kumar@...com>
Cc: baruch@...s.co.il, grant.likely@...retlab.ca,
linux-kernel@...r.kernel.org, armando.visconti@...com,
shiraz.hashim@...com, vipin.kumar@...com, rajeev-dlh.kumar@...com,
deepak.sikri@...com, vipulkumar.samar@...com, amit.virdi@...com,
pratyush.anand@...com, bhupesh.sharma@...com,
viresh.linux@...il.com, bhavna.yadav@...com,
vincenzo.frascino@...com, mirko.gardi@...com
Subject: Re: [PATCH] GPIO/pl061: Add suspend resume capability
On Thursday, November 17, 2011, Viresh Kumar wrote:
> From: Deepak Sikri <deepak.sikri@...com>
>
> This patch adds the suspend and resume operations in the driver. The patch
> ensures the data save and restore for the device registers during the
> suspend and resume operations respectively.
>
> Signed-off-by: Deepak Sikri <deepak.sikri@...com>
> ---
> drivers/gpio/gpio-pl061.c | 73 +++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 73 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
> index 093c90b..d64dc1c 100644
> --- a/drivers/gpio/gpio-pl061.c
> +++ b/drivers/gpio/gpio-pl061.c
> @@ -23,6 +23,7 @@
> #include <linux/amba/bus.h>
> #include <linux/amba/pl061.h>
> #include <linux/slab.h>
> +#include <linux/pm.h>
>
> #define GPIODIR 0x400
> #define GPIOIS 0x404
> @@ -35,6 +36,17 @@
>
> #define PL061_GPIO_NR 8
>
> +#ifdef CONFIG_PM
> +struct gpio_context_save_regs {
> + u8 gpio_data;
> + u8 gpio_dir;
> + u8 gpio_is;
> + u8 gpio_ibe;
> + u8 gpio_iev;
> + u8 gpio_ie;
> +};
> +#endif
> +
> struct pl061_gpio {
> /* We use a list of pl061_gpio structs for each trigger IRQ in the main
> * interrupts controller of the system. We need this to support systems
> @@ -54,6 +66,10 @@ struct pl061_gpio {
> void __iomem *base;
> unsigned irq_base;
> struct gpio_chip gc;
> +
> +#ifdef CONFIG_PM
> + struct gpio_context_save_regs csave_regs;
> +#endif
> };
>
> static int pl061_direction_input(struct gpio_chip *gc, unsigned offset)
> @@ -330,6 +346,8 @@ static int pl061_probe(struct amba_device *dev, const struct amba_id *id)
> irq_set_chip_data(i + chip->irq_base, chip);
> }
>
> + amba_set_drvdata(dev, chip);
> +
> return 0;
>
> iounmap:
> @@ -342,6 +360,60 @@ free_mem:
> return ret;
> }
>
> +#ifdef CONFIG_PM
> +static int pl061_suspend(struct device *dev)
> +{
> + struct pl061_gpio *chip = dev_get_drvdata(dev);
> + int offset;
> +
> + chip->csave_regs.gpio_data = 0;
> + chip->csave_regs.gpio_dir = readb(chip->base + GPIODIR);
> + chip->csave_regs.gpio_is = readb(chip->base + GPIOIS);
> + chip->csave_regs.gpio_ibe = readb(chip->base + GPIOIBE);
> + chip->csave_regs.gpio_iev = readb(chip->base + GPIOIEV);
> + chip->csave_regs.gpio_ie = readb(chip->base + GPIOIE);
> +
> + for (offset = 0; offset < PL061_GPIO_NR; offset++) {
> + if (chip->csave_regs.gpio_dir & (1 << offset))
> + chip->csave_regs.gpio_data |=
> + pl061_get_value(&chip->gc, offset) << offset;
> + }
> +
> + return 0;
> +}
> +
> +static int pl061_resume(struct device *dev)
> +{
> + struct pl061_gpio *chip = dev_get_drvdata(dev);
> + int offset;
> +
> + for (offset = 0; offset < PL061_GPIO_NR; offset++) {
> + if (chip->csave_regs.gpio_dir & (1 << offset))
> + pl061_direction_output(&chip->gc, offset,
> + chip->csave_regs.gpio_data &
> + (1 << offset));
> + else
> + pl061_direction_input(&chip->gc, offset);
> + }
> +
> + writeb(chip->csave_regs.gpio_is, chip->base + GPIOIS);
> + writeb(chip->csave_regs.gpio_ibe, chip->base + GPIOIBE);
> + writeb(chip->csave_regs.gpio_iev, chip->base + GPIOIEV);
> + writeb(chip->csave_regs.gpio_ie, chip->base + GPIOIE);
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops pl061_dev_pm_ops = {
> + .suspend = pl061_suspend,
> + .resume = pl061_resume,
Please also include hibernation callbacks here, otherwise your code will
break systems with hibernation enabled.
There are convenience macros for that in linux/pm.h, please use one of them.
Thanks,
Rafael
> +};
> +
> +#define PL061_DEV_PM_OPS (&pl061_dev_pm_ops)
> +#else
> +#define PL061_DEV_PM_OPS NULL
> +#endif
> +
> static struct amba_id pl061_ids[] = {
> {
> .id = 0x00041061,
> @@ -353,6 +425,7 @@ static struct amba_id pl061_ids[] = {
> static struct amba_driver pl061_gpio_driver = {
> .drv = {
> .name = "pl061_gpio",
> + .pm = PL061_DEV_PM_OPS,
> },
> .id_table = pl061_ids,
> .probe = pl061_probe,
>
--
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