linux-kernel - [PATCH] pinctrl: amd: print debounce filter info in debugfs

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Message-Id: <20201024061552.4497-1-coiby.xu@gmail.com>
Date:   Sat, 24 Oct 2020 14:15:52 +0800
From:   Coiby Xu <coiby.xu@...il.com>
To:     linux-gpio@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Hans de Goede <hdegoede@...hat.com>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] pinctrl: amd: print debounce filter info in debugfs

Print out the status of debounce filter as follows,
$ cat /sys/kernel/debug/gpio|grep pin130
pin130          interrupt is disabled| interrupt is masked| disable wakeup in S0i3 state| disable wakeup in S3 state|
 disable wakeup in S4/S5 state| input is high|   pull-up is disabled| Pull-down is disabled|   output is disabled| debouncing filter (high) enabled| debouncing timeout is 124800 (us)| 0x503c8

Signed-off-by: Coiby Xu <coiby.xu@...il.com>
---
 drivers/pinctrl/pinctrl-amd.c | 43 +++++++++++++++++++++++++++++++++--
 1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 9a760f5cd7ed..9897f86b1bec 100644
--- a/drivers/pinctrl/pinctrl-amd.c
+++ b/drivers/pinctrl/pinctrl-amd.c
@@ -197,10 +197,16 @@ static int amd_gpio_set_config(struct gpio_chip *gc, unsigned offset,
 static void amd_gpio_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 {
 	u32 pin_reg;
+	u32 reg_db_mask;
 	unsigned long flags;
 	unsigned int bank, i, pin_num;
 	struct amd_gpio *gpio_dev = gpiochip_get_data(gc);
 
+	bool tmr_out_unit;
+	unsigned int time;
+	unsigned int unit;
+	bool tmr_large;
+
 	char *level_trig;
 	char *active_level;
 	char *interrupt_enable;
@@ -214,6 +220,8 @@ static void amd_gpio_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 	char *pull_down_enable;
 	char *output_value;
 	char *output_enable;
+	char debounce_value[40];
+	char *debounce_enable;
 
 	for (bank = 0; bank < gpio_dev->hwbank_num; bank++) {
 		seq_printf(s, "GPIO bank%d\t", bank);
@@ -327,13 +335,44 @@ static void amd_gpio_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 					pin_sts = "input is low|";
 			}
 
+			reg_db_mask = (DB_CNTRl_MASK << DB_CNTRL_OFF) & pin_reg;
+			if (reg_db_mask & pin_reg) {
+				tmr_out_unit = pin_reg & BIT(DB_TMR_OUT_UNIT_OFF);
+				tmr_large = pin_reg & BIT(DB_TMR_LARGE_OFF);
+				time = pin_reg & DB_TMR_OUT_MASK;
+				if (!tmr_large) {
+					if (!tmr_out_unit)
+						unit = 61;
+					else
+						unit = 244;
+				} else {
+					if (!tmr_out_unit)
+						unit = 15600;
+					else
+						unit = 62500;
+				}
+				if ((DB_TYPE_REMOVE_GLITCH << DB_CNTRL_OFF) == reg_db_mask)
+					debounce_enable = "debouncing filter (high and low) enabled|";
+				else if ((DB_TYPE_PRESERVE_LOW_GLITCH << DB_CNTRL_OFF) == reg_db_mask)
+					debounce_enable = "debouncing filter (low) enabled|";
+				else
+					debounce_enable = "debouncing filter (high) enabled|";
+
+				snprintf(debounce_value, 40,
+					 "debouncing timeout is %u (us)|", time * unit);
+			} else {
+				debounce_enable = "debouncing filter disabled|";
+				snprintf(debounce_value, 30, " ");
+			}
+
 			seq_printf(s, "%s %s %s %s %s %s\n"
-				" %s %s %s %s %s %s %s 0x%x\n",
+				" %s %s %s %s %s %s %s %s %s 0x%x\n",
 				level_trig, active_level, interrupt_enable,
 				interrupt_mask, wake_cntrl0, wake_cntrl1,
 				wake_cntrl2, pin_sts, pull_up_sel,
 				pull_up_enable, pull_down_enable,
-				output_value, output_enable, pin_reg);
+				output_value, output_enable,
+				debounce_enable, debounce_value, pin_reg);
 		}
 	}
 }
-- 
2.28.0