gpio: omap: Save and restore sysconfig

As we are using cpu_pm to save and restore context, we must also save and
restore the timer sysconfig register TIOCP_CFG. This is needed because
we are not calling PM runtime functions at all with cpu_pm.

We need to save the sysconfig on idle as it's value can get reconfigured by
PM runtime and can be different from the init time value. Device specific
flags like "ti,no-idle-on-init" can affect the init value.

Fixes: b764a5863fd8 ("gpio: omap: Remove custom PM calls and use cpu_pm instead")
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Adam Ford <aford173@gmail.com>
Cc: Andreas Kemnade <andreas@kemnade.info>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/gpio/gpio-omap.c                | 9 +++++++++
 include/linux/platform_data/gpio-omap.h | 3 +++
 2 files changed, 12 insertions(+)

On 15/04/2021 11:53, Tony Lindgren wrote:
> As we are using cpu_pm to save and restore context, we must also save and
> restore the timer sysconfig register TIOCP_CFG. This is needed because
> we are not calling PM runtime functions at all with cpu_pm.

Smth. is wrong with description.

> 
> We need to save the sysconfig on idle as it's value can get reconfigured by
> PM runtime and can be different from the init time value. Device specific
> flags like "ti,no-idle-on-init" can affect the init value.
> 
> Fixes: b764a5863fd8 ("gpio: omap: Remove custom PM calls and use cpu_pm instead")
> Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
> Cc: Adam Ford <aford173@gmail.com>
> Cc: Andreas Kemnade <andreas@kemnade.info>
> Cc: Grygorii Strashko <grygorii.strashko@ti.com>
> Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>   drivers/gpio/gpio-omap.c                | 9 +++++++++
>   include/linux/platform_data/gpio-omap.h | 3 +++
>   2 files changed, 12 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> --- a/drivers/gpio/gpio-omap.c
> +++ b/drivers/gpio/gpio-omap.c
> @@ -29,6 +29,7 @@
>   #define OMAP4_GPIO_DEBOUNCINGTIME_MASK 0xFF
>   
>   struct gpio_regs {
> +	u32 sysconfig;
>   	u32 irqenable1;
>   	u32 irqenable2;
>   	u32 wake_en;
> @@ -1069,6 +1070,7 @@ static void omap_gpio_init_context(struct gpio_bank *p)
>   	const struct omap_gpio_reg_offs *regs = p->regs;
>   	void __iomem *base = p->base;
>   
> +	p->context.sysconfig	= readl_relaxed(base + regs->sysconfig);
>   	p->context.ctrl		= readl_relaxed(base + regs->ctrl);
>   	p->context.oe		= readl_relaxed(base + regs->direction);
>   	p->context.wake_en	= readl_relaxed(base + regs->wkup_en);
> @@ -1088,6 +1090,7 @@ static void omap_gpio_restore_context(struct gpio_bank *bank)
>   	const struct omap_gpio_reg_offs *regs = bank->regs;
>   	void __iomem *base = bank->base;
>   
> +	writel_relaxed(bank->context.sysconfig, base + regs->sysconfig);
>   	writel_relaxed(bank->context.wake_en, base + regs->wkup_en);
>   	writel_relaxed(bank->context.ctrl, base + regs->ctrl);
>   	writel_relaxed(bank->context.leveldetect0, base + regs->leveldetect0);
> @@ -1115,6 +1118,10 @@ static void omap_gpio_idle(struct gpio_bank *bank, bool may_lose_context)
>   
>   	bank->saved_datain = readl_relaxed(base + bank->regs->datain);
>   
> +	/* Save syconfig, it's runtime value can be different from init value */
> +	if (bank->loses_context)
> +		bank->context.sysconfig = readl_relaxed(base + bank->regs->sysconfig);
> +
>   	if (!bank->enabled_non_wakeup_gpios)
>   		goto update_gpio_context_count;
>   
> @@ -1279,6 +1286,7 @@ static int gpio_omap_cpu_notifier(struct notifier_block *nb,
>   
>   static const struct omap_gpio_reg_offs omap2_gpio_regs = {
>   	.revision =		OMAP24XX_GPIO_REVISION,
> +	.sysconfig =		OMAP24XX_GPIO_SYSCONFIG,
>   	.direction =		OMAP24XX_GPIO_OE,
>   	.datain =		OMAP24XX_GPIO_DATAIN,
>   	.dataout =		OMAP24XX_GPIO_DATAOUT,
> @@ -1302,6 +1310,7 @@ static const struct omap_gpio_reg_offs omap2_gpio_regs = {
>   
>   static const struct omap_gpio_reg_offs omap4_gpio_regs = {
>   	.revision =		OMAP4_GPIO_REVISION,
> +	.sysconfig =		OMAP4_GPIO_SYSCONFIG,
>   	.direction =		OMAP4_GPIO_OE,
>   	.datain =		OMAP4_GPIO_DATAIN,
>   	.dataout =		OMAP4_GPIO_DATAOUT,
> diff --git a/include/linux/platform_data/gpio-omap.h b/include/linux/platform_data/gpio-omap.h
> --- a/include/linux/platform_data/gpio-omap.h
> +++ b/include/linux/platform_data/gpio-omap.h
> @@ -85,6 +85,7 @@
>    * omap2+ specific GPIO registers
>    */
>   #define OMAP24XX_GPIO_REVISION		0x0000
> +#define OMAP24XX_GPIO_SYSCONFIG		0x0010
>   #define OMAP24XX_GPIO_IRQSTATUS1	0x0018
>   #define OMAP24XX_GPIO_IRQSTATUS2	0x0028
>   #define OMAP24XX_GPIO_IRQENABLE2	0x002c
> @@ -108,6 +109,7 @@
>   #define OMAP24XX_GPIO_SETDATAOUT	0x0094
>   
>   #define OMAP4_GPIO_REVISION		0x0000
> +#define OMAP4_GPIO_SYSCONFIG		0x0010
>   #define OMAP4_GPIO_EOI			0x0020
>   #define OMAP4_GPIO_IRQSTATUSRAW0	0x0024
>   #define OMAP4_GPIO_IRQSTATUSRAW1	0x0028
> @@ -148,6 +150,7 @@
>   #ifndef __ASSEMBLER__
>   struct omap_gpio_reg_offs {
>   	u16 revision;
> +	u16 sysconfig;
>   	u16 direction;
>   	u16 datain;
>   	u16 dataout;
>

* Grygorii Strashko <grygorii.strashko@ti.com> [210415 23:48]:
> On 15/04/2021 11:53, Tony Lindgren wrote:
> > As we are using cpu_pm to save and restore context, we must also save and
> > restore the timer sysconfig register TIOCP_CFG. This is needed because
> > we are not calling PM runtime functions at all with cpu_pm.
> 
> Smth. is wrong with description.

Oops yeah sorry about that. Both timer-ti-dm and gpio-omap suffer from
the same issue since the cpu_pm conversion. Will post v2.

Regards,

Tony