Re: [PATCH] gpio: omap: Remove custom PM calls and use cpu_pm instead

[Ladislav Michl <ladis@linux-mips.org>]

Tony,

On Tue, Sep 11, 2018 at 11:37:29AM -0700, Tony Lindgren wrote:
> For a long time the gpio-omap custom PM calls have been annoying me so
> let's replace them with cpu_pm instead. This will enable GPIO PM for
> deeper idle states on omap4. And we can handle GPIO PM for omap2/3/4
> in the same way.
> 
> Note that with this patch we are also slightly changing GPIO PM to be
> less aggressive for omap3 and only will idle GPIO when PER context
> may be lost.

I do not think it will make things any worse, but will run my favorite
latency on test on this patch :)

Meanwhile see nit bellow.

> For omap2, we don't need to save context and don't want to remove any
> triggering so let's add a quirk flag for that.
> 
> Let's do this all in a single patch to avoid a situation where old
> custom calls still are used with new code.
> 
> Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
> Cc: Grygorii Strashko <grygorii.strashko@ti.com>
> Cc: Keerthy <j-keerthy@ti.com>
> Cc: Ladislav Michl <ladis@linux-mips.org>
> Cc: Tero Kristo <t-kristo@ti.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
> 
> Note that this depends on previously posted patch:
> 
> [PATCH] gpio: omap: Add level wakeup handling for omap4 based SoCs
> 
> Linus, once people are happy with these, can you maybe set up an
> immutable branch with both patches in it?
> 
> ---
>  arch/arm/mach-omap2/pm24xx.c            |  7 +--
>  arch/arm/mach-omap2/pm34xx.c            | 14 ++---
>  drivers/gpio/gpio-omap.c                | 78 +++++++++++++++----------
>  include/linux/platform_data/gpio-omap.h | 13 -----
>  4 files changed, 55 insertions(+), 57 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/pm24xx.c b/arch/arm/mach-omap2/pm24xx.c
> --- a/arch/arm/mach-omap2/pm24xx.c
> +++ b/arch/arm/mach-omap2/pm24xx.c
> @@ -18,6 +18,7 @@
>   * published by the Free Software Foundation.
>   */
>  
> +#include <linux/cpu_pm.h>
>  #include <linux/suspend.h>
>  #include <linux/sched.h>
>  #include <linux/proc_fs.h>
> @@ -29,8 +30,6 @@
>  #include <linux/clk-provider.h>
>  #include <linux/irq.h>
>  #include <linux/time.h>
> -#include <linux/gpio.h>
> -#include <linux/platform_data/gpio-omap.h>
>  
>  #include <asm/fncpy.h>
>  
> @@ -87,7 +86,7 @@ static int omap2_enter_full_retention(void)
>  	l = omap_ctrl_readl(OMAP2_CONTROL_DEVCONF0) | OMAP24XX_USBSTANDBYCTRL;
>  	omap_ctrl_writel(l, OMAP2_CONTROL_DEVCONF0);
>  
> -	omap2_gpio_prepare_for_idle(0);
> +	cpu_cluster_pm_enter();
>  
>  	/* One last check for pending IRQs to avoid extra latency due
>  	 * to sleeping unnecessarily. */
> @@ -100,7 +99,7 @@ static int omap2_enter_full_retention(void)
>  			   OMAP_SDRC_REGADDR(SDRC_POWER));
>  
>  no_sleep:
> -	omap2_gpio_resume_after_idle();
> +	cpu_cluster_pm_exit();
>  
>  	clk_enable(osc_ck);
>  
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -18,19 +18,18 @@
>   * published by the Free Software Foundation.
>   */
>  
> +#include <linux/cpu_pm.h>
>  #include <linux/pm.h>
>  #include <linux/suspend.h>
>  #include <linux/interrupt.h>
>  #include <linux/module.h>
>  #include <linux/list.h>
>  #include <linux/err.h>
> -#include <linux/gpio.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/slab.h>
>  #include <linux/omap-dma.h>
>  #include <linux/omap-gpmc.h>
> -#include <linux/platform_data/gpio-omap.h>
>  
>  #include <trace/events/power.h>
>  
> @@ -197,7 +196,6 @@ void omap_sram_idle(void)
>  	int mpu_next_state = PWRDM_POWER_ON;
>  	int per_next_state = PWRDM_POWER_ON;
>  	int core_next_state = PWRDM_POWER_ON;
> -	int per_going_off;
>  	u32 sdrc_pwr = 0;
>  
>  	mpu_next_state = pwrdm_read_next_pwrst(mpu_pwrdm);
> @@ -227,10 +225,8 @@ void omap_sram_idle(void)
>  	pwrdm_pre_transition(NULL);
>  
>  	/* PER */
> -	if (per_next_state < PWRDM_POWER_ON) {
> -		per_going_off = (per_next_state == PWRDM_POWER_OFF) ? 1 : 0;
> -		omap2_gpio_prepare_for_idle(per_going_off);
> -	}
> +	if (per_next_state == PWRDM_POWER_OFF)
> +		cpu_cluster_pm_enter();
>  
>  	/* CORE */
>  	if (core_next_state < PWRDM_POWER_ON) {
> @@ -295,8 +291,8 @@ void omap_sram_idle(void)
>  	pwrdm_post_transition(NULL);
>  
>  	/* PER */
> -	if (per_next_state < PWRDM_POWER_ON)
> -		omap2_gpio_resume_after_idle();
> +	if (per_next_state == PWRDM_POWER_OFF)
> +		cpu_cluster_pm_exit();
>  }
>  
>  static void omap3_pm_idle(void)
> 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
> @@ -19,6 +19,7 @@
>  #include <linux/err.h>
>  #include <linux/clk.h>
>  #include <linux/io.h>
> +#include <linux/cpu_pm.h>
>  #include <linux/device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/pm.h>
> @@ -31,6 +32,7 @@
>  #define OFF_MODE	1
>  #define OMAP4_GPIO_DEBOUNCINGTIME_MASK 0xFF
>  
> +#define OMAP_GPIO_QUIRK_IDLE_REMOVE_TRIGGER	BIT(2)
>  #define OMAP_GPIO_QUIRK_DEFERRED_WKUP_EN	BIT(1)
>  
>  static LIST_HEAD(omap_gpio_list);
> @@ -72,6 +74,7 @@ struct gpio_bank {
>  	raw_spinlock_t wa_lock;
>  	struct gpio_chip chip;
>  	struct clk *dbck;
> +	struct notifier_block nb;
>  	u32 mod_usage;
>  	u32 irq_usage;
>  	u32 dbck_enable_mask;
> @@ -1308,6 +1311,38 @@ static int omap_gpio_chip_init(struct gpio_bank *bank, struct irq_chip *irqc)
>  	return ret;
>  }
>  
> +static int gpio_omap_cpu_notifier(struct notifier_block *nb,
> +				  unsigned long cmd, void *v)
> +{
> +	struct gpio_bank *bank;
> +	struct device *dev;
> +	int error;
> +
> +	bank = container_of(nb, struct gpio_bank, nb);
> +	dev = bank->chip.parent;
> +
> +	switch (cmd) {
> +	case CPU_CLUSTER_PM_ENTER:
> +		/* Gets cleard on runtime_suspend */

"Gets cleared" perhaps...

> +		bank->power_mode = OFF_MODE;
> +
> +		error = pm_runtime_put_sync(dev);
> +		if (error < 0)
> +			dev_warn(dev, "CPU PM enter: %i\n", error);
> +		break;
> +	case CPU_CLUSTER_PM_ENTER_FAILED:
> +	case CPU_CLUSTER_PM_EXIT:
> +		error = pm_runtime_get_sync(dev);
> +		if (error < 0) {
> +			dev_err(dev, "CPU PM exit %i\n", error);
> +			pm_runtime_put_noidle(dev);
> +		}
> +		break;
> +	}
> +
> +	return NOTIFY_OK;
> +}
> +
>  static const struct of_device_id omap_gpio_match[];
>  
>  static int omap_gpio_probe(struct platform_device *pdev)
> @@ -1445,6 +1480,9 @@ static int omap_gpio_probe(struct platform_device *pdev)
>  
>  	omap_gpio_show_rev(bank);
>  
> +	bank->nb.notifier_call = gpio_omap_cpu_notifier;
> +	cpu_pm_register_notifier(&bank->nb);
> +
>  	pm_runtime_put(dev);
>  
>  	list_add_tail(&bank->node, &omap_gpio_list);
> @@ -1456,6 +1494,7 @@ static int omap_gpio_remove(struct platform_device *pdev)
>  {
>  	struct gpio_bank *bank = platform_get_drvdata(pdev);
>  
> +	cpu_pm_unregister_notifier(&bank->nb);
>  	list_del(&bank->node);
>  	gpiochip_remove(&bank->chip);
>  	pm_runtime_disable(&pdev->dev);
> @@ -1622,37 +1661,7 @@ static int omap_gpio_runtime_resume(struct device *dev)
>  
>  	return 0;
>  }
> -#endif /* CONFIG_PM */
> -
> -#if IS_BUILTIN(CONFIG_GPIO_OMAP)
> -void omap2_gpio_prepare_for_idle(int pwr_mode)
> -{
> -	struct gpio_bank *bank;
>  
> -	list_for_each_entry(bank, &omap_gpio_list, node) {
> -		if (!BANK_USED(bank) || !bank->loses_context)
> -			continue;
> -
> -		bank->power_mode = pwr_mode;
> -
> -		pm_runtime_put_sync_suspend(bank->chip.parent);
> -	}
> -}
> -
> -void omap2_gpio_resume_after_idle(void)
> -{
> -	struct gpio_bank *bank;
> -
> -	list_for_each_entry(bank, &omap_gpio_list, node) {
> -		if (!BANK_USED(bank) || !bank->loses_context)
> -			continue;
> -
> -		pm_runtime_get_sync(bank->chip.parent);
> -	}
> -}
> -#endif
> -
> -#if defined(CONFIG_PM)
>  static void omap_gpio_init_context(struct gpio_bank *p)
>  {
>  	struct omap_gpio_reg_offs *regs = p->regs;
> @@ -1768,6 +1777,11 @@ static struct omap_gpio_reg_offs omap4_gpio_regs = {
>  	.fallingdetect =	OMAP4_GPIO_FALLINGDETECT,
>  };
>  
> +/*
> + * Note that omap2 does not currently support idle modes with context loss so
> + * no need to add OMAP_GPIO_QUIRK_IDLE_REMOVE_TRIGGER quirk flag to save
> + * and restore context.
> + */
>  static const struct omap_gpio_platform_data omap2_pdata = {
>  	.regs = &omap2_gpio_regs,
>  	.bank_width = 32,
> @@ -1778,13 +1792,15 @@ static const struct omap_gpio_platform_data omap3_pdata = {
>  	.regs = &omap2_gpio_regs,
>  	.bank_width = 32,
>  	.dbck_flag = true,
> +	.quirks = OMAP_GPIO_QUIRK_IDLE_REMOVE_TRIGGER,
>  };
>  
>  static const struct omap_gpio_platform_data omap4_pdata = {
>  	.regs = &omap4_gpio_regs,
>  	.bank_width = 32,
>  	.dbck_flag = true,
> -	.quirks = OMAP_GPIO_QUIRK_DEFERRED_WKUP_EN,
> +	.quirks = OMAP_GPIO_QUIRK_IDLE_REMOVE_TRIGGER |
> +		  OMAP_GPIO_QUIRK_DEFERRED_WKUP_EN,
>  };
>  
>  static const struct of_device_id omap_gpio_match[] = {
> 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
> @@ -205,17 +205,4 @@ struct omap_gpio_platform_data {
>  	int (*get_context_loss_count)(struct device *dev);
>  };
>  
> -#if IS_BUILTIN(CONFIG_GPIO_OMAP)
> -extern void omap2_gpio_prepare_for_idle(int off_mode);
> -extern void omap2_gpio_resume_after_idle(void);
> -#else
> -static inline void omap2_gpio_prepare_for_idle(int off_mode)
> -{
> -}
> -
> -static inline void omap2_gpio_resume_after_idle(void)
> -{
> -}
> -#endif
> -
>  #endif
> -- 
> 2.18.0