Re: [PATCH v2 1/2] input: keyboard: snvs_pwrkey: Send key events for i.MX6 S, DL and Q

Hi Marco,

On 2019-08-28 11:15, Marco Felsch wrote:

Hi Robin,

thanks for the patch.

On 19-08-27 14:32, Robin van der Gracht wrote:

quoted

The first generation i.MX6 processors does not send an interrupt when 
the
power key is pressed. It sends a power down request interrupt if the 
key is
released before a hard shutdown (5 second press). This should allow
software to bring down the SoC safely.

For this driver to work as a regular power key with the older SoCs, we 
need
to send a keypress AND release when we get the power down request irq.

Signed-off-by: Robin van der Gracht <robin@protonic.nl>
---
 .../devicetree/bindings/crypto/fsl-sec4.txt   | 16 ++++--
 drivers/input/keyboard/Kconfig                |  2 +-
 drivers/input/keyboard/snvs_pwrkey.c          | 52 
++++++++++++++++---

Can we split this so the dt-bindings are a standalone patch? IMHO this
is the usual way because the maintainer can squash them on there needs.

Not sure what you mean, do you want me to make a separate patch for the
devicetree binding documentation here?

Also it would be cool to document the changes. A common place for
changes is after the '---' or on the cover-letter.

Agreed!

v1 -> v2:
  - Nolonger altering the existing compatible string, just add a second 
one.
  - Moved the event emiting work out of the irq handler to the timer 
handler.
  - Assign hwtype directly to of_device_id->data instead of a struct
    platform_device_id entry which has it's .driver_data set to hwtype.
  - Document the new device tree binding.
  - Update commit message to make more clear why we want to make this 
change.

quoted

 3 files changed, 57 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt 

b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
index 2fe245ca816a..e4fbb9797082 100644

--- a/Documentation/devicetree/bindings/crypto/fsl-sec4.txt
+++ b/Documentation/devicetree/bindings/crypto/fsl-sec4.txt

@@ -420,14 +420,22 @@ EXAMPLE
 =====================================================================
 System ON/OFF key driver

-  The snvs-pwrkey is designed to enable POWER key function which 

controlled
-  by SNVS ONOFF, the driver can report the status of POWER key and 
wakeup
-  system if pressed after system suspend.
+  The snvs-pwrkey is designed to enable POWER key function which is 
controlled
+  by SNVS ONOFF. It can wakeup the system if pressed after system 
suspend.
+
+  There are two generations of SVNS pwrkey hardware. The first 
generation is
+  included in i.MX6 Solo, DualLite and Quad processors. The second 
generation
+  is included in i.MX6 SoloX and newer SoCs.
+
+  Second generation SNVS can detect and report the status of POWER 
key, but the
+  first generation can only detect a key release and so emits an 
instantaneous
+  press and release event when the key is released.

   - compatible:
       Usage: required
       Value type: <string>
-      Definition: Mush include "fsl,sec-v4.0-pwrkey".
+      Definition: Must include "fsl,sec-v4.0-pwrkey" for i.MX6 SoloX 
and newer
+	   or "fsl,imx6qdl-snvs-pwrkey" for older SoCs.

   - interrupts:
       Usage: required

diff --git a/drivers/input/keyboard/Kconfig 

b/drivers/input/keyboard/Kconfig
index 7c4f19dab34f..937e58da5ce1 100644

--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig

@@ -436,7 +436,7 @@ config KEYBOARD_SNVS_PWRKEY
 	depends on OF
 	help
 	  This is the snvs powerkey driver for the Freescale i.MX 

application
-	  processors that are newer than i.MX6 SX.
+	  processors.

 	  To compile this driver as a module, choose M here; the
 	  module will be called snvs_pwrkey.

diff --git a/drivers/input/keyboard/snvs_pwrkey.c 

b/drivers/input/keyboard/snvs_pwrkey.c
index 5342d8d45f81..d71c44733103 100644

--- a/drivers/input/keyboard/snvs_pwrkey.c
+++ b/drivers/input/keyboard/snvs_pwrkey.c

@@ -29,6 +29,11 @@
 #define DEBOUNCE_TIME 30
 #define REPEAT_INTERVAL 60

+enum imx_snvs_hwtype {
+	IMX6SX_SNVS,	/* i.MX6 SoloX and newer */
+	IMX6QDL_SNVS,	/* i.MX6 Solo, DualLite and Quad */
+};
+
 struct pwrkey_drv_data {
 	struct regmap *snvs;
 	int irq;

@@ -37,14 +42,41 @@ struct pwrkey_drv_data {
 	int wakeup;
 	struct timer_list check_timer;
 	struct input_dev *input;
+	enum imx_snvs_hwtype hwtype;
 };

+static const struct of_device_id imx_snvs_pwrkey_ids[] = {
+	{
+		.compatible = "fsl,sec-v4.0-pwrkey",
+		.data = (const void *)IMX6SX_SNVS,
+	},
+	{
+		.compatible = "fsl,imx6qdl-snvs-pwrkey",
+		.data = (const void *)IMX6QDL_SNVS,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, imx_snvs_pwrkey_ids);

Can we keep this on the original place if you are using ...

quoted

+
 static void imx_imx_snvs_check_for_events(struct timer_list *t)
 {
 	struct pwrkey_drv_data *pdata = from_timer(pdata, t, check_timer);
 	struct input_dev *input = pdata->input;
 	u32 state;

+	if (pdata->hwtype == IMX6QDL_SNVS) {
+		/*
+		 * The first generation i.MX6 SoCs only sends an interrupt on
+		 * button release. To mimic power-key usage, we'll prepend a
+		 * press event.
+		 */
+		input_report_key(input, pdata->keycode, 1);

Missing input_sync() here?

Yes you are right. Odd that systemd powerkey handling didn't complain.

quoted

+		input_report_key(input, pdata->keycode, 0);
+		input_sync(input);
+		pm_relax(input->dev.parent);
+		return;
+	}
+
 	regmap_read(pdata->snvs, SNVS_HPSR_REG, &state);
 	state = state & SNVS_HPSR_BTN ? 1 : 0;

@@ -67,13 +99,17 @@ static irqreturn_t imx_snvs_pwrkey_interrupt(int 

irq, void *dev_id)
 {
 	struct platform_device *pdev = dev_id;
 	struct pwrkey_drv_data *pdata = platform_get_drvdata(pdev);
+	unsigned long expire = jiffies;
 	u32 lp_status;

 	pm_wakeup_event(pdata->input->dev.parent, 0);

 	regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status);
-	if (lp_status & SNVS_LPSR_SPO)
-		mod_timer(&pdata->check_timer, jiffies + 
msecs_to_jiffies(DEBOUNCE_TIME));
+	if (lp_status & SNVS_LPSR_SPO) {
+		if (pdata->hwtype == IMX6SX_SNVS)
+			expire += msecs_to_jiffies(DEBOUNCE_TIME);
+		mod_timer(&pdata->check_timer, expire);

Is this desired because the timer gets triggered earlier.

Yes, since the first generation has debounce implemented in hardware,
we dont need to add another one.

Now looking at it, maybe I should change the conditional to:

if (pdata->hwtype != IMX6QDL_SNVS)
         expire += msecs_to_jiffies(DEBOUNCE_TIME);

to make this more clear.

quoted

+	}

 	/* clear SPO status */
 	regmap_write(pdata->snvs, SNVS_LPSR_REG, SNVS_LPSR_SPO);

@@ -93,6 +129,7 @@ static int imx_snvs_pwrkey_probe(struct 

platform_device *pdev)
 	struct pwrkey_drv_data *pdata = NULL;
 	struct input_dev *input = NULL;
 	struct device_node *np;
+	const struct of_device_id *match;
 	int error;

 	/* Get SNVS register Page */

@@ -100,6 +137,10 @@ static int imx_snvs_pwrkey_probe(struct 

platform_device *pdev)
 	if (!np)
 		return -ENODEV;

+	match = of_match_node(imx_snvs_pwrkey_ids, np);
+	if (!match)
+		return -ENODEV;

... of_device_get_match_data() here.

of_device_get_match_data() returns NULL on error. In this case, because 
I
assigned integer values to the .data pointers, casting NULL back to an
integer will result in a valid hwtype.

I could declare a special struct with a 'quirks' field like they did in 
the
flexcan diver: 'drivers/net/can/flexcan.c'.

Use of_device_get_match_data() to get it, and define a quirk like:
SNVS_QUIRK_NO_BTN_PRESS_IRQ. This might also improve readability.

While reading the rm it seems that
the snvs block has a dedicated version register. IMHO this could be a
better way to apply the change also to existing devices with old
firmware.

I thought the same thing, and fully agree with you. However I do not 
have
a way to determine which versions are out there. Since I couldn't find 
any
documentation on this, and I only have i.MX6 S/DL, D/Q and UL laying 
around.

Regards,
Robin van der Gracht