[PATCH 0/7] Miscellaneous fixes for Azoteq IQS7222A/B/C

[PATCH 0/7] Miscellaneous fixes for Azoteq IQS7222A/B/C

[Jeff LaBundy]

This series comprises a handful of minor fixes that result from
continued testing and updated guidance from the vendor.

Jeff LaBundy (7):
  Input: iqs7222 - fortify slider event reporting
  Input: iqs7222 - protect volatile registers
  Input: iqs7222 - acknowledge reset before writing registers
  Input: iqs7222 - handle reset during ATI
  Input: iqs7222 - remove support for RF filter
  dt-bindings: input: iqs7222: Remove support for RF filter
  dt-bindings: input: iqs7222: Correct bottom speed step size

 .../bindings/input/azoteq,iqs7222.yaml        |   7 +-
 drivers/input/misc/iqs7222.c                  | 132 ++++++++++++------
 2 files changed, 90 insertions(+), 49 deletions(-)

-- 
2.25.1

[PATCH 1/7] Input: iqs7222 - fortify slider event reporting

[Jeff LaBundy]

The release cycle of any key mapped to a slider gesture relies upon
trailing interrupts generated by other unmasked sources, the timing
and presence of which are inconsistent.

To solve this problem, explicitly report a release cycle to emulate
a full keystroke. Also, unmask touch interrupts if the slider press
event is defined; this ensures the device reports a final interrupt
with coordinate = 0xFFFF once the finger is lifted.

As part of this change, use the device's resolution rather than its
number of interrupt status registers to more safely determine if it
is capable of reporting gestures.

Last but not least, make the code a bit simpler by eliminating some
unnecessarily complex conditional statements and a macro that could
be derived using information that is already available.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/input/misc/iqs7222.c | 66 ++++++++++++++++++++++--------------
 1 file changed, 40 insertions(+), 26 deletions(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index 6b4138771a3f..6cfabd6e3a15 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -40,7 +40,6 @@
 #define IQS7222_SLDR_SETUP_2_RES_MASK		GENMASK(15, 8)
 #define IQS7222_SLDR_SETUP_2_RES_SHIFT		8
 #define IQS7222_SLDR_SETUP_2_TOP_SPEED_MASK	GENMASK(7, 0)
-#define IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK	GENMASK(9, 0)
 
 #define IQS7222_GPIO_SETUP_0_GPIO_EN		BIT(0)
 
@@ -54,6 +53,9 @@
 #define IQS7222_SYS_SETUP_ACK_RESET		BIT(0)
 
 #define IQS7222_EVENT_MASK_ATI			BIT(12)
+#define IQS7222_EVENT_MASK_SLDR			BIT(10)
+#define IQS7222_EVENT_MASK_TOUCH		BIT(1)
+#define IQS7222_EVENT_MASK_PROX			BIT(0)
 
 #define IQS7222_COMMS_HOLD			BIT(0)
 #define IQS7222_COMMS_ERROR			0xEEEE
@@ -135,12 +137,12 @@ struct iqs7222_event_desc {
 static const struct iqs7222_event_desc iqs7222_kp_events[] = {
 	{
 		.name = "event-prox",
-		.enable = BIT(0),
+		.enable = IQS7222_EVENT_MASK_PROX,
 		.reg_key = IQS7222_REG_KEY_PROX,
 	},
 	{
 		.name = "event-touch",
-		.enable = BIT(1),
+		.enable = IQS7222_EVENT_MASK_TOUCH,
 		.reg_key = IQS7222_REG_KEY_TOUCH,
 	},
 };
@@ -1957,8 +1959,8 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
 	int num_chan = dev_desc->reg_grps[IQS7222_REG_GRP_CHAN].num_row;
 	int ext_chan = rounddown(num_chan, 10);
 	int count, error, reg_offset, i;
+	u16 *event_mask = &iqs7222->sys_setup[dev_desc->event_offset];
 	u16 *sldr_setup = iqs7222->sldr_setup[sldr_index];
-	u16 *sys_setup = iqs7222->sys_setup;
 	unsigned int chan_sel[4], val;
 
 	error = iqs7222_parse_props(iqs7222, &sldr_node, sldr_index,
@@ -2003,7 +2005,7 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
 	reg_offset = dev_desc->sldr_res < U16_MAX ? 0 : 1;
 
 	sldr_setup[0] |= count;
-	sldr_setup[3 + reg_offset] &= ~IQS7222_SLDR_SETUP_3_CHAN_SEL_MASK;
+	sldr_setup[3 + reg_offset] &= ~GENMASK(ext_chan - 1, 0);
 
 	for (i = 0; i < ARRAY_SIZE(chan_sel); i++) {
 		sldr_setup[5 + reg_offset + i] = 0;
@@ -2120,7 +2122,13 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
 		 * coordinate field reports 0xFFFF and has no explicit enable
 		 * control.
 		 */
-		if (!iqs7222_sl_events[i].enable || reg_offset)
+		if (!iqs7222_sl_events[i].enable) {
+			if (dev_desc->event_offset)
+				*event_mask |= IQS7222_EVENT_MASK_TOUCH;
+			continue;
+		}
+
+		if (reg_offset)
 			continue;
 
 		sldr_setup[9] |= iqs7222_sl_events[i].enable;
@@ -2131,10 +2139,8 @@ static int iqs7222_parse_sldr(struct iqs7222_private *iqs7222, int sldr_index)
 		if (error)
 			return error;
 
-		if (!dev_desc->event_offset)
-			continue;
-
-		sys_setup[dev_desc->event_offset] |= BIT(10 + sldr_index);
+		if (dev_desc->event_offset)
+			*event_mask |= (IQS7222_EVENT_MASK_SLDR << sldr_index);
 	}
 
 	/*
@@ -2299,29 +2305,37 @@ static int iqs7222_report(struct iqs7222_private *iqs7222)
 			input_report_abs(iqs7222->keypad, iqs7222->sl_axis[i],
 					 sldr_pos);
 
-		for (j = 0; j < ARRAY_SIZE(iqs7222_sl_events); j++) {
-			u16 mask = iqs7222_sl_events[j].mask;
-			u16 val = iqs7222_sl_events[j].val;
+		input_report_key(iqs7222->keypad, iqs7222->sl_code[i][0],
+				 sldr_pos < dev_desc->sldr_res);
 
-			if (!iqs7222_sl_events[j].enable) {
-				input_report_key(iqs7222->keypad,
-						 iqs7222->sl_code[i][j],
-						 sldr_pos < dev_desc->sldr_res);
-				continue;
-			}
+		/*
+		 * A maximum resolution indicates the device does not support
+		 * gestures, in which case the remaining fields are ignored.
+		 */
+		if (dev_desc->sldr_res == U16_MAX)
+			continue;
 
-			/*
-			 * The remaining offsets represent gesture state, and
-			 * are discarded in the case of IQS7222C because only
-			 * absolute position is reported.
-			 */
-			if (num_stat < IQS7222_MAX_COLS_STAT)
-				continue;
+		if (!(le16_to_cpu(status[1]) & IQS7222_EVENT_MASK_SLDR << i))
+			continue;
+
+		/*
+		 * Skip the press/release event, as it does not have separate
+		 * status fields and is handled separately.
+		 */
+		for (j = 1; j < ARRAY_SIZE(iqs7222_sl_events); j++) {
+			u16 mask = iqs7222_sl_events[j].mask;
+			u16 val = iqs7222_sl_events[j].val;
 
 			input_report_key(iqs7222->keypad,
 					 iqs7222->sl_code[i][j],
 					 (state & mask) == val);
 		}
+
+		input_sync(iqs7222->keypad);
+
+		for (j = 1; j < ARRAY_SIZE(iqs7222_sl_events); j++)
+			input_report_key(iqs7222->keypad,
+					 iqs7222->sl_code[i][j], 0);
 	}
 
 	input_sync(iqs7222->keypad);
-- 
2.25.1

[PATCH 2/7] Input: iqs7222 - protect volatile registers

[Jeff LaBundy]

Select variants of silicon silently mirror part of the event mask
register to the system setup register (0xD0), and vice versa. For
the following sequence:

1. Read registers 0xD0 onward and store their contents.
2. Modify the contents, including event mask fields.
3. Write registers 0xD0 onward with the modified contents.
4. Write register 0xD0 on its own again later, using the contents
   from step 1 to populate any reserved fields.

...the event mask register (e.g. address 0xDA) has been corrupted
by writing register 0xD0 with contents that were made stale after
step 3.

To solve this problem, read register 0xD0 once more between steps
3 and 4. When register 0xD0 is written during step 4, the portion
which is mirrored to the event mask register already matches what
was written in step 3.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/input/misc/iqs7222.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index 6cfabd6e3a15..ed5989093713 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -1274,9 +1274,22 @@ static int iqs7222_ati_trigger(struct iqs7222_private *iqs7222)
 	struct i2c_client *client = iqs7222->client;
 	ktime_t ati_timeout;
 	u16 sys_status = 0;
-	u16 sys_setup = iqs7222->sys_setup[0] & ~IQS7222_SYS_SETUP_ACK_RESET;
+	u16 sys_setup;
 	int error, i;
 
+	/*
+	 * The reserved fields of the system setup register may have changed
+	 * as a result of other registers having been written. As such, read
+	 * the register's latest value to avoid unexpected behavior when the
+	 * register is written in the loop that follows.
+	 */
+	error = iqs7222_read_word(iqs7222, IQS7222_SYS_SETUP, &sys_setup);
+	if (error)
+		return error;
+
+	sys_setup &= ~IQS7222_SYS_SETUP_INTF_MODE_MASK;
+	sys_setup &= ~IQS7222_SYS_SETUP_PWR_MODE_MASK;
+
 	for (i = 0; i < IQS7222_NUM_RETRIES; i++) {
 		/*
 		 * Trigger ATI from streaming and normal-power modes so that
@@ -2233,9 +2246,6 @@ static int iqs7222_parse_all(struct iqs7222_private *iqs7222)
 			return error;
 	}
 
-	sys_setup[0] &= ~IQS7222_SYS_SETUP_INTF_MODE_MASK;
-	sys_setup[0] &= ~IQS7222_SYS_SETUP_PWR_MODE_MASK;
-
 	sys_setup[0] |= IQS7222_SYS_SETUP_ACK_RESET;
 
 	return iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_SYS,
-- 
2.25.1

[PATCH 3/7] Input: iqs7222 - acknowledge reset before writing registers

[Jeff LaBundy]

If the device suffers a spurious reset while reacting to a previous
spurious reset, the second reset interrupt is preempted because the
ACK_RESET bit is written last.

To solve this problem, write the ACK_RESET bit prior to writing any
other registers. This ensures that any registers written before the
second spurious reset will be rewritten.

Last but not least, the order in which the ACK_RESET bit is written
relative to the second filter beta register is important for select
variants of silicon. Enforce the correct order so as to not clobber
the system status register.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/input/misc/iqs7222.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index ed5989093713..c1ead10dccbe 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -94,11 +94,11 @@ enum iqs7222_reg_key_id {
 
 enum iqs7222_reg_grp_id {
 	IQS7222_REG_GRP_STAT,
+	IQS7222_REG_GRP_FILT,
 	IQS7222_REG_GRP_CYCLE,
 	IQS7222_REG_GRP_GLBL,
 	IQS7222_REG_GRP_BTN,
 	IQS7222_REG_GRP_CHAN,
-	IQS7222_REG_GRP_FILT,
 	IQS7222_REG_GRP_SLDR,
 	IQS7222_REG_GRP_GPIO,
 	IQS7222_REG_GRP_SYS,
@@ -1348,6 +1348,34 @@ static int iqs7222_dev_init(struct iqs7222_private *iqs7222, int dir)
 	int comms_offset = dev_desc->comms_offset;
 	int error, i, j, k;
 
+	/*
+	 * Acknowledge reset before writing any registers in case the device
+	 * suffers a spurious reset during initialization. Because this step
+	 * may change the reserved fields of the second filter beta register,
+	 * its cache must be updated.
+	 *
+	 * Writing the second filter beta register, in turn, may clobber the
+	 * system status register. As such, the filter beta register pair is
+	 * written first to protect against this hazard.
+	 */
+	if (dir == WRITE) {
+		u16 reg = dev_desc->reg_grps[IQS7222_REG_GRP_FILT].base + 1;
+		u16 filt_setup;
+
+		error = iqs7222_write_word(iqs7222, IQS7222_SYS_SETUP,
+					   iqs7222->sys_setup[0] |
+					   IQS7222_SYS_SETUP_ACK_RESET);
+		if (error)
+			return error;
+
+		error = iqs7222_read_word(iqs7222, reg, &filt_setup);
+		if (error)
+			return error;
+
+		iqs7222->filt_setup[1] &= GENMASK(7, 0);
+		iqs7222->filt_setup[1] |= (filt_setup & ~GENMASK(7, 0));
+	}
+
 	/*
 	 * Take advantage of the stop-bit disable function, if available, to
 	 * save the trouble of having to reopen a communication window after
@@ -2246,8 +2274,6 @@ static int iqs7222_parse_all(struct iqs7222_private *iqs7222)
 			return error;
 	}
 
-	sys_setup[0] |= IQS7222_SYS_SETUP_ACK_RESET;
-
 	return iqs7222_parse_props(iqs7222, NULL, 0, IQS7222_REG_GRP_SYS,
 				   IQS7222_REG_KEY_NONE);
 }
-- 
2.25.1

[PATCH 4/7] Input: iqs7222 - handle reset during ATI

[Jeff LaBundy]

If the device suffers a spurious reset during ATI, there is no point
in enduring any further retries. Instead, simply return successfully
from the polling loop.

In this case, the interrupt handler will intervene and recognize the
device has been reset. It then proceeds to initialize the device and
trigger ATI once more.

As part of this change, swap the order of status field evaluation to
match that of the interrupt handler, and correct a nearby off-by-one
error that causes an error message to suggest the final attempt will
be retried.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/input/misc/iqs7222.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index c1ead10dccbe..a84cc18638df 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -1314,12 +1314,15 @@ static int iqs7222_ati_trigger(struct iqs7222_private *iqs7222)
 			if (error)
 				return error;
 
-			if (sys_status & IQS7222_SYS_STATUS_ATI_ACTIVE)
-				continue;
+			if (sys_status & IQS7222_SYS_STATUS_RESET)
+				return 0;
 
 			if (sys_status & IQS7222_SYS_STATUS_ATI_ERROR)
 				break;
 
+			if (sys_status & IQS7222_SYS_STATUS_ATI_ACTIVE)
+				continue;
+
 			/*
 			 * Use stream-in-touch mode if either slider reports
 			 * absolute position.
@@ -1336,7 +1339,7 @@ static int iqs7222_ati_trigger(struct iqs7222_private *iqs7222)
 		dev_err(&client->dev,
 			"ATI attempt %d of %d failed with status 0x%02X, %s\n",
 			i + 1, IQS7222_NUM_RETRIES, (u8)sys_status,
-			i < IQS7222_NUM_RETRIES ? "retrying..." : "stopping");
+			i + 1 < IQS7222_NUM_RETRIES ? "retrying" : "stopping");
 	}
 
 	return -ETIMEDOUT;
-- 
2.25.1

[PATCH 5/7] Input: iqs7222 - remove support for RF filter

[Jeff LaBundy]

The vendor has redacted the RF filter enable control; remove it from
the driver.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 drivers/input/misc/iqs7222.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index a84cc18638df..d1d36d857e55 100644
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -557,13 +557,6 @@ static const struct iqs7222_prop_desc iqs7222_props[] = {
 		.reg_width = 4,
 		.label = "current reference trim",
 	},
-	{
-		.name = "azoteq,rf-filt-enable",
-		.reg_grp = IQS7222_REG_GRP_GLBL,
-		.reg_offset = 0,
-		.reg_shift = 15,
-		.reg_width = 1,
-	},
 	{
 		.name = "azoteq,max-counts",
 		.reg_grp = IQS7222_REG_GRP_GLBL,
-- 
2.25.1

[PATCH 6/7] dt-bindings: input: iqs7222: Remove support for RF filter

[Jeff LaBundy]

The vendor has redacted the RF filter enable control; remove it from
the binding.

Fixes: 44dc42d254bf ("dt-bindings: input: Add bindings for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml b/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
index a3a1e5a65306..6180f7ee2284 100644
--- a/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
+++ b/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
@@ -37,10 +37,6 @@ properties:
       device is temporarily held in hardware reset prior to initialization if
       this property is present.
 
-  azoteq,rf-filt-enable:
-    type: boolean
-    description: Enables the device's internal RF filter.
-
   azoteq,max-counts:
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 1, 2, 3]
-- 
2.25.1

[PATCH 7/7] dt-bindings: input: iqs7222: Correct bottom speed step size

[Jeff LaBundy]

The bottom speed property is specified in steps of 1, not 4.

Fixes: 44dc42d254bf ("dt-bindings: input: Add bindings for Azoteq IQS7222A/B/C")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
---
 Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml b/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
index 6180f7ee2284..c9c3a1e9bcae 100644
--- a/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
+++ b/Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml
@@ -533,9 +533,8 @@ patternProperties:
 
       azoteq,bottom-speed:
         $ref: /schemas/types.yaml#/definitions/uint32
-        multipleOf: 4
         minimum: 0
-        maximum: 1020
+        maximum: 255
         description:
           Specifies the speed of movement after which coordinate filtering is
           linearly reduced.
-- 
2.25.1

Re: [PATCH 5/7] Input: iqs7222 - remove support for RF filter

[Dmitry Torokhov]

On Wed, Jun 22, 2022 at 10:53:07PM -0500, Jeff LaBundy wrote:
> The vendor has redacted the RF filter enable control; remove it from

Did you mean "retracted" by chance?

Thanks.

-- 
Dmitry

Re: [PATCH 5/7] Input: iqs7222 - remove support for RF filter

[Jeff LaBundy]

Hi Dmitry,

On Thu, Jun 23, 2022 at 06:05:27PM -0700, Dmitry Torokhov wrote:
> On Wed, Jun 22, 2022 at 10:53:07PM -0500, Jeff LaBundy wrote:
> > The vendor has redacted the RF filter enable control; remove it from
> 
> Did you mean "retracted" by chance?

I did mean redact, as in 'to censor,' as the field has since been
marked reserved in the datasheet since silicon was released.

That being said, I'm happy to re-spin with this stated explicitly
in case of poor word choice on my part.

> 
> Thanks.
> 
> -- 
> Dmitry

Kind regards,
Jeff LaBundy