linux-kernel - [RFC PATCH] Input: omap4-keypad: react on keypresses if device is runtime-suspended

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Message-Id: <20230929200046.2300333-1-andreas@kemnade.info>
Date:   Fri, 29 Sep 2023 22:00:46 +0200
From:   Andreas Kemnade <andreas@...nade.info>
To:     dmitry.torokhov@...il.com, Jonathan.Cameron@...wei.com,
        andreas@...nade.info, robh@...nel.org, frank.li@...o.com,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, tony@...mide.com
Subject: [RFC PATCH] Input: omap4-keypad: react on keypresses if device is runtime-suspended

According to SWPU235AB, table 26-6, fclk is required to generate events
at least on OMAP4460, so keep fclk enabled all the time the device
is opened.

Suggested-by: Tony Lindgren <tony@...mide.com>
Signed-off-by: Andreas Kemnade <andreas@...nade.info>
---
Open questions:
- Should we rather (or also use) padconf irqs?
- It seems not to be required everywhere. Does it harm somewhere?

 drivers/input/keyboard/omap4-keypad.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
index 773e55eed88b1..a7585a09c48b4 100644
--- a/drivers/input/keyboard/omap4-keypad.c
+++ b/drivers/input/keyboard/omap4-keypad.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
+#include <linux/clk.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/of.h>
@@ -83,6 +84,7 @@ struct omap4_keypad {
 	bool no_autorepeat;
 	u64 keys;
 	unsigned short *keymap;
+	struct clk *fck;
 };
 
 static int kbd_readl(struct omap4_keypad *keypad_data, u32 offset)
@@ -211,6 +213,8 @@ static int omap4_keypad_open(struct input_dev *input)
 
 	disable_irq(keypad_data->irq);
 
+	clk_prepare_enable(keypad_data->fck);
+
 	kbd_writel(keypad_data, OMAP4_KBD_CTRL,
 			OMAP4_DEF_CTRL_NOSOFTMODE |
 			(OMAP4_KEYPAD_PTV_DIV_128 << OMAP4_DEF_CTRL_PTV_SHIFT));
@@ -258,6 +262,7 @@ static void omap4_keypad_close(struct input_dev *input)
 	disable_irq(keypad_data->irq);
 	omap4_keypad_stop(keypad_data);
 	enable_irq(keypad_data->irq);
+	clk_disable_unprepare(keypad_data->fck);
 
 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);
@@ -356,6 +361,11 @@ static int omap4_keypad_probe(struct platform_device *pdev)
 	}
 
 	keypad_data->irq = irq;
+	keypad_data->fck = devm_clk_get(&pdev->dev, "fck");
+	if (IS_ERR(keypad_data->fck))
+		return dev_err_probe(&pdev->dev, PTR_ERR(keypad_data->fck),
+				     "unable to get fck");
+
 	mutex_init(&keypad_data->lock);
 	platform_set_drvdata(pdev, keypad_data);
 
-- 
2.39.2