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

From: robin
Date: Thu Aug 29 2019 - 03:24:16 EST

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:
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@xxxxxxxxxxx>
.../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.


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.

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
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

+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 ...

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.

+ 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.

+ }

/* 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

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.

Robin van der Gracht