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Date: Fri, 17 May 2013 16:38:10 +0200
From: Tomasz Figa <t.figa@...sung.com>
To: Doug Anderson <dianders@...omium.org>
Cc: Tomasz Figa <tomasz.figa@...il.com>,
Kukjin Kim <kgene.kim@...sung.com>,
Heiko Stübner <heiko@...ech.de>,
Olof Johansson <olof@...om.net>,
Stephen Warren <swarren@...dotorg.org>,
Thomas Abraham <thomas.abraham@...aro.org>,
Linus Walleij <linus.walleij@...aro.org>,
Prathyush K <prathyush.k@...sung.com>,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] pinctrl: samsung: fix suspend/resume functionality
Hi Doug,
On Thursday 16 of May 2013 21:33:18 Doug Anderson wrote:
> The GPIO states need to be restored after s2r and this is not currently
> supported in the pinctrl driver. This patch saves the gpio states before
> suspend and restores them after resume.
>
> Saving and restoring is done very early using syscore_ops and must
> happen before pins are released from their powerdown state.
>
> Patch originally from Prathyush K <prathyush.k@...sung.com> but
> rewritten by Doug Anderson <dianders@...omium.org>.
>
> Signed-off-by: Prathyush K <prathyush.k@...sung.com>
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
> Changes in v3:
> - Skip save and restore for banks with no powerdown config.
>
> Changes in v2:
> - Now uses sycore_ops to make sure we're early enough.
> - Try to handle two CON registers better.
> - Should handle s3c24xx better as per Heiko.
> - Simpler code; no longer tries to avoid glitching lines since
> we _think_ all current SoCs should have pins in power down state
> when the restore is called.
> - Dropped eint patch for now; Tomasz will post his version.
>
> drivers/pinctrl/pinctrl-samsung.c | 148
> ++++++++++++++++++++++++++++++++++++++ drivers/pinctrl/pinctrl-samsung.h |
> 5 ++
> 2 files changed, 153 insertions(+)
On Exynos4210-based Trats board:
Tested-by: Tomasz Figa <t.figa@...sung.com>
Acked-by: Tomasz Figa <t.figa@...sung.com>
I will send several complementary patches in a while.
Best regards,
--
Tomasz Figa
Linux Kernel Developer
Samsung R&D Institute Poland
Samsung Electronics
> diff --git a/drivers/pinctrl/pinctrl-samsung.c
> b/drivers/pinctrl/pinctrl-samsung.c index 9763668..d45e36f 100644
> --- a/drivers/pinctrl/pinctrl-samsung.c
> +++ b/drivers/pinctrl/pinctrl-samsung.c
> @@ -28,6 +28,7 @@
> #include <linux/gpio.h>
> #include <linux/irqdomain.h>
> #include <linux/spinlock.h>
> +#include <linux/syscore_ops.h>
>
> #include "core.h"
> #include "pinctrl-samsung.h"
> @@ -48,6 +49,9 @@ static struct pin_config {
> { "samsung,pin-pud-pdn", PINCFG_TYPE_PUD_PDN },
> };
>
> +/* Global list of devices (struct samsung_pinctrl_drv_data) */
> +LIST_HEAD(drvdata_list);
> +
> static unsigned int pin_base;
>
> static inline struct samsung_pin_bank *gc_to_pin_bank(struct gpio_chip *gc)
> @@ -961,9 +965,145 @@ static int samsung_pinctrl_probe(struct
> platform_device *pdev) ctrl->eint_wkup_init(drvdata);
>
> platform_set_drvdata(pdev, drvdata);
> +
> + /* Add to the global list */
> + list_add_tail(&drvdata->node, &drvdata_list);
> +
> return 0;
> }
>
> +#ifdef CONFIG_PM
> +
> +/**
> + * samsung_pinctrl_suspend_dev - save pinctrl state for suspend for a
> device + *
> + * Save data for all banks handled by this device.
> + */
> +static void samsung_pinctrl_suspend_dev(
> + struct samsung_pinctrl_drv_data *drvdata)
> +{
> + struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
> + void __iomem *virt_base = drvdata->virt_base;
> + int i;
> +
> + for (i = 0; i < ctrl->nr_banks; i++) {
> + struct samsung_pin_bank *bank = &ctrl->pin_banks[i];
> + void __iomem *reg = virt_base + bank->pctl_offset;
> +
> + u8 *offs = bank->type->reg_offset;
> + u8 *widths = bank->type->fld_width;
> + enum pincfg_type type;
> +
> + /* Registers without a powerdown config aren't lost */
> + if (!widths[PINCFG_TYPE_CON_PDN])
> + continue;
> +
> + for (type = 0; type < PINCFG_TYPE_NUM; type++)
> + if (widths[type])
> + bank->pm_save[type] = readl(reg + offs[type]);
> +
> + if (widths[PINCFG_TYPE_FUNC] * bank->nr_pins > 32) {
> + /* Some banks have two config registers */
> + bank->pm_save[PINCFG_TYPE_NUM] =
> + readl(reg + offs[PINCFG_TYPE_FUNC] + 4);
> + pr_debug("Save %s @ %p (con %#010x %08x)\n",
> + bank->name, reg,
> + bank->pm_save[PINCFG_TYPE_FUNC],
> + bank->pm_save[PINCFG_TYPE_NUM]);
> + } else {
> + pr_debug("Save %s @ %p (con %#010x)\n", bank->name,
> + reg, bank->pm_save[PINCFG_TYPE_FUNC]);
> + }
> + }
> +}
> +
> +/**
> + * samsung_pinctrl_resume_dev - restore pinctrl state from suspend for a
> device + *
> + * Restore one of the banks that was saved during suspend.
> + *
> + * We don't bother doing anything complicated to avoid glitching lines
> since + * we're called before pad retention is turned off.
> + */
> +static void samsung_pinctrl_resume_dev(struct samsung_pinctrl_drv_data
> *drvdata) +{
> + struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
> + void __iomem *virt_base = drvdata->virt_base;
> + int i;
> +
> + for (i = 0; i < ctrl->nr_banks; i++) {
> + struct samsung_pin_bank *bank = &ctrl->pin_banks[i];
> + void __iomem *reg = virt_base + bank->pctl_offset;
> +
> + u8 *offs = bank->type->reg_offset;
> + u8 *widths = bank->type->fld_width;
> + enum pincfg_type type;
> +
> + /* Registers without a powerdown config aren't lost */
> + if (!widths[PINCFG_TYPE_CON_PDN])
> + continue;
> +
> + if (widths[PINCFG_TYPE_FUNC] * bank->nr_pins > 32) {
> + /* Some banks have two config registers */
> + pr_debug("%s @ %p (con %#010x %08x => %#010x %08x)\n",
> + bank->name, reg,
> + readl(reg + offs[PINCFG_TYPE_FUNC]),
> + readl(reg + offs[PINCFG_TYPE_FUNC] + 4),
> + bank->pm_save[PINCFG_TYPE_FUNC],
> + bank->pm_save[PINCFG_TYPE_NUM]);
> + writel(bank->pm_save[PINCFG_TYPE_NUM],
> + reg + offs[PINCFG_TYPE_FUNC] + 4);
> + } else {
> + pr_debug("%s @ %p (con %#010x => %#010x)\n", bank->name,
> + reg, readl(reg + offs[PINCFG_TYPE_FUNC]),
> + bank->pm_save[PINCFG_TYPE_FUNC]);
> + }
> + for (type = 0; type < PINCFG_TYPE_NUM; type++)
> + if (widths[type])
> + writel(bank->pm_save[type], reg + offs[type]);
> + }
> +}
> +
> +/**
> + * samsung_pinctrl_suspend - save pinctrl state for suspend
> + *
> + * Save data for all banks across all devices.
> + */
> +static int samsung_pinctrl_suspend(void)
> +{
> + struct samsung_pinctrl_drv_data *drvdata;
> +
> + list_for_each_entry(drvdata, &drvdata_list, node) {
> + samsung_pinctrl_suspend_dev(drvdata);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * samsung_pinctrl_resume - restore pinctrl state for suspend
> + *
> + * Restore data for all banks across all devices.
> + */
> +static void samsung_pinctrl_resume(void)
> +{
> + struct samsung_pinctrl_drv_data *drvdata;
> +
> + list_for_each_entry_reverse(drvdata, &drvdata_list, node) {
> + samsung_pinctrl_resume_dev(drvdata);
> + }
> +}
> +
> +#else
> +#define samsung_pinctrl_suspend NULL
> +#define samsung_pinctrl_resume NULL
> +#endif
> +
> +static struct syscore_ops samsung_pinctrl_syscore_ops = {
> + .suspend = samsung_pinctrl_suspend,
> + .resume = samsung_pinctrl_resume,
> +};
> +
> static const struct of_device_id samsung_pinctrl_dt_match[] = {
> #ifdef CONFIG_PINCTRL_EXYNOS
> { .compatible = "samsung,exynos4210-pinctrl",
> @@ -992,6 +1132,14 @@ static struct platform_driver samsung_pinctrl_driver =
> {
>
> static int __init samsung_pinctrl_drv_register(void)
> {
> + /*
> + * Register syscore ops for save/restore of registers across suspend.
> + * It's important to ensure that this driver is running at an earlier
> + * initcall level than any arch-specific init calls that install syscore
> + * ops that turn off pad retention (like exynos_pm_resume).
> + */
> + register_syscore_ops(&samsung_pinctrl_syscore_ops);
> +
> return platform_driver_register(&samsung_pinctrl_driver);
> }
> postcore_initcall(samsung_pinctrl_drv_register);
> diff --git a/drivers/pinctrl/pinctrl-samsung.h
> b/drivers/pinctrl/pinctrl-samsung.h index 7c7f9eb..9f5cc81 100644
> --- a/drivers/pinctrl/pinctrl-samsung.h
> +++ b/drivers/pinctrl/pinctrl-samsung.h
> @@ -127,6 +127,7 @@ struct samsung_pin_bank_type {
> * @gpio_chip: GPIO chip of the bank.
> * @grange: linux gpio pin range supported by this bank.
> * @slock: spinlock protecting bank registers
> + * @pm_save: saved register values during suspend
> */
> struct samsung_pin_bank {
> struct samsung_pin_bank_type *type;
> @@ -144,6 +145,8 @@ struct samsung_pin_bank {
> struct gpio_chip gpio_chip;
> struct pinctrl_gpio_range grange;
> spinlock_t slock;
> +
> + u32 pm_save[PINCFG_TYPE_NUM + 1]; /* +1 to handle double CON registers*/
> };
>
> /**
> @@ -189,6 +192,7 @@ struct samsung_pin_ctrl {
>
> /**
> * struct samsung_pinctrl_drv_data: wrapper for holding driver data
> together. + * @node: global list node
> * @virt_base: register base address of the controller.
> * @dev: device instance representing the controller.
> * @irq: interrpt number used by the controller to notify gpio interrupts.
> @@ -201,6 +205,7 @@ struct samsung_pin_ctrl {
> * @nr_function: number of such pin functions.
> */
> struct samsung_pinctrl_drv_data {
> + struct list_head node;
> void __iomem *virt_base;
> struct device *dev;
> int irq;
--
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