diff mbox series

[v7,03/48] Input: atmel_mxt_ts - only read messages in mxt_acquire_irq() when necessary

Message ID 20200212084218.32344-4-jiada_wang@mentor.com (mailing list archive)
State Superseded
Headers show
Series atmel_mxt_ts misc | expand

Commit Message

Wang, Jiada Feb. 12, 2020, 8:41 a.m. UTC
From: Nick Dyer <nick.dyer@itdev.co.uk>

The workaround of reading all messages until an invalid is received is a
way of forcing the CHG line high, which means that when using
edge-triggered interrupts the interrupt can be acquired.

With level-triggered interrupts the workaround is unnecessary.

Also, most recent maXTouch chips have a feature called RETRIGEN which, when
enabled, reasserts the interrupt line every cycle if there are messages
waiting. This also makes the workaround unnecessary.

Note: the RETRIGEN feature is only in some firmware versions/chips, it's
not valid simply to enable the bit.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
(cherry picked from ndyer/linux/for-upstream commit 1ae4e8281e491b22442cd5acdfca1862555f8ecb)
[gdavis: Fix conflicts due to v4.6-rc7 commit eb43335c4095 ("Input:
	 atmel_mxt_ts - use mxt_acquire_irq in mxt_soft_reset").]
Signed-off-by: George G. Davis <george_davis@mentor.com>
[jiada: reset use_retrigen_workaround at beginning of mxt_check_retrigen()]
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 51 ++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 3 deletions(-)

Comments

Dmitry Osipenko March 17, 2020, 10:44 p.m. UTC | #1
12.02.2020 11:41, Jiada Wang пишет:
> From: Nick Dyer <nick.dyer@itdev.co.uk>
> 
> The workaround of reading all messages until an invalid is received is a
> way of forcing the CHG line high, which means that when using
> edge-triggered interrupts the interrupt can be acquired.
> 
> With level-triggered interrupts the workaround is unnecessary.
> 
> Also, most recent maXTouch chips have a feature called RETRIGEN which, when
> enabled, reasserts the interrupt line every cycle if there are messages
> waiting. This also makes the workaround unnecessary.
> 
> Note: the RETRIGEN feature is only in some firmware versions/chips, it's
> not valid simply to enable the bit.

...
> +static int mxt_check_retrigen(struct mxt_data *data)
> +{
> +	struct i2c_client *client = data->client;
> +	int error;
> +	int val;
> +
> +	data->use_retrigen_workaround = false;
> +
> +	if (irq_get_trigger_type(data->irq) & IRQF_TRIGGER_LOW)
> +		return 0;
> +
> +	if (data->T18_address) {
> +		error = __mxt_read_reg(client,
> +				       data->T18_address + MXT_COMMS_CTRL,
> +				       1, &val);
> +		if (error)
> +			return error;
> +
> +		if (val & MXT_COMMS_RETRIGEN)
> +			return 0;
> +	}
> +
> +	dev_warn(&client->dev, "Enabling RETRIGEN workaround\n");
> +	data->use_retrigen_workaround = true;
> +	return 0;
> +}

Hello Jiada,

I'm seeing "Enabling RETRIGEN workaround" message with the following
device-tree entry:

touchscreen@4c {
	compatible = "atmel,maxtouch";
	reg = <0x4c>;

	interrupt-parent = <&gpio>;
	interrupts = <TEGRA_GPIO(V, 6) IRQ_TYPE_LEVEL_LOW>;

	reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_HIGH>;
};

This happens because data->irq is NULL. Please fix it, thanks in advance.
Wang, Jiada March 18, 2020, 1:02 p.m. UTC | #2
Hello Dmitry

On 2020/03/18 7:44, Dmitry Osipenko wrote:
> 12.02.2020 11:41, Jiada Wang пишет:
>> From: Nick Dyer <nick.dyer@itdev.co.uk>
>>
>> The workaround of reading all messages until an invalid is received is a
>> way of forcing the CHG line high, which means that when using
>> edge-triggered interrupts the interrupt can be acquired.
>>
>> With level-triggered interrupts the workaround is unnecessary.
>>
>> Also, most recent maXTouch chips have a feature called RETRIGEN which, when
>> enabled, reasserts the interrupt line every cycle if there are messages
>> waiting. This also makes the workaround unnecessary.
>>
>> Note: the RETRIGEN feature is only in some firmware versions/chips, it's
>> not valid simply to enable the bit.
> 
> ...
>> +static int mxt_check_retrigen(struct mxt_data *data)
>> +{
>> +	struct i2c_client *client = data->client;
>> +	int error;
>> +	int val;
>> +
>> +	data->use_retrigen_workaround = false;
>> +
>> +	if (irq_get_trigger_type(data->irq) & IRQF_TRIGGER_LOW)
>> +		return 0;
>> +
>> +	if (data->T18_address) {
>> +		error = __mxt_read_reg(client,
>> +				       data->T18_address + MXT_COMMS_CTRL,
>> +				       1, &val);
>> +		if (error)
>> +			return error;
>> +
>> +		if (val & MXT_COMMS_RETRIGEN)
>> +			return 0;
>> +	}
>> +
>> +	dev_warn(&client->dev, "Enabling RETRIGEN workaround\n");
>> +	data->use_retrigen_workaround = true;
>> +	return 0;
>> +}
> 
> Hello Jiada,
> 
> I'm seeing "Enabling RETRIGEN workaround" message with the following
> device-tree entry:
> 
> touchscreen@4c {
> 	compatible = "atmel,maxtouch";
> 	reg = <0x4c>;
> 
> 	interrupt-parent = <&gpio>;
> 	interrupts = <TEGRA_GPIO(V, 6) IRQ_TYPE_LEVEL_LOW>;
> 
> 	reset-gpios = <&gpio TEGRA_GPIO(Q, 7) GPIO_ACTIVE_HIGH>;
> };
> 
> This happens because data->irq is NULL. Please fix it, thanks in advance.
Thanks for reporting this issue,
I will fix this issue in v8 patch-set

Thanks,
Jiada
>
diff mbox series

Patch

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 550caec1018e..e184d0e67ef8 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -20,6 +20,7 @@ 
 #include <linux/i2c.h>
 #include <linux/input/mt.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/property.h>
 #include <linux/slab.h>
@@ -129,6 +130,7 @@  struct t9_range {
 /* MXT_SPT_COMMSCONFIG_T18 */
 #define MXT_COMMS_CTRL		0
 #define MXT_COMMS_CMD		1
+#define MXT_COMMS_RETRIGEN      BIT(6)
 
 /* MXT_DEBUG_DIAGNOSTIC_T37 */
 #define MXT_DIAGNOSTIC_PAGEUP	0x01
@@ -308,6 +310,7 @@  struct mxt_data {
 	struct t7_config t7_cfg;
 	struct mxt_dbg dbg;
 	struct gpio_desc *reset_gpio;
+	bool use_retrigen_workaround;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -318,6 +321,7 @@  struct mxt_data {
 	u16 T71_address;
 	u8 T9_reportid_min;
 	u8 T9_reportid_max;
+	u16 T18_address;
 	u8 T19_reportid;
 	u16 T44_address;
 	u8 T100_reportid_min;
@@ -1190,9 +1194,11 @@  static int mxt_acquire_irq(struct mxt_data *data)
 
 	enable_irq(data->irq);
 
-	error = mxt_process_messages_until_invalid(data);
-	if (error)
-		return error;
+	if (data->use_retrigen_workaround) {
+		error = mxt_process_messages_until_invalid(data);
+		if (error)
+			return error;
+	}
 
 	return 0;
 }
@@ -1282,6 +1288,33 @@  static u32 mxt_calculate_crc(u8 *base, off_t start_off, off_t end_off)
 	return crc;
 }
 
+static int mxt_check_retrigen(struct mxt_data *data)
+{
+	struct i2c_client *client = data->client;
+	int error;
+	int val;
+
+	data->use_retrigen_workaround = false;
+
+	if (irq_get_trigger_type(data->irq) & IRQF_TRIGGER_LOW)
+		return 0;
+
+	if (data->T18_address) {
+		error = __mxt_read_reg(client,
+				       data->T18_address + MXT_COMMS_CTRL,
+				       1, &val);
+		if (error)
+			return error;
+
+		if (val & MXT_COMMS_RETRIGEN)
+			return 0;
+	}
+
+	dev_warn(&client->dev, "Enabling RETRIGEN workaround\n");
+	data->use_retrigen_workaround = true;
+	return 0;
+}
+
 static int mxt_prepare_cfg_mem(struct mxt_data *data, struct mxt_cfg *cfg)
 {
 	struct device *dev = &data->client->dev;
@@ -1561,6 +1594,10 @@  static int mxt_update_cfg(struct mxt_data *data, const struct firmware *fw)
 
 	mxt_update_crc(data, MXT_COMMAND_BACKUPNV, MXT_BACKUP_VALUE);
 
+	ret = mxt_check_retrigen(data);
+	if (ret)
+		goto release_mem;
+
 	ret = mxt_soft_reset(data);
 	if (ret)
 		goto release_mem;
@@ -1604,6 +1641,7 @@  static void mxt_free_object_table(struct mxt_data *data)
 	data->T71_address = 0;
 	data->T9_reportid_min = 0;
 	data->T9_reportid_max = 0;
+	data->T18_address = 0;
 	data->T19_reportid = 0;
 	data->T44_address = 0;
 	data->T100_reportid_min = 0;
@@ -1678,6 +1716,9 @@  static int mxt_parse_object_table(struct mxt_data *data,
 						object->num_report_ids - 1;
 			data->num_touchids = object->num_report_ids;
 			break;
+		case MXT_SPT_COMMSCONFIG_T18:
+			data->T18_address = object->start_address;
+			break;
 		case MXT_SPT_MESSAGECOUNT_T44:
 			data->T44_address = object->start_address;
 			break;
@@ -2141,6 +2182,10 @@  static int mxt_initialize(struct mxt_data *data)
 		msleep(MXT_FW_RESET_TIME);
 	}
 
+	error = mxt_check_retrigen(data);
+	if (error)
+		return error;
+
 	error = mxt_acquire_irq(data);
 	if (error)
 		return error;