Input: iqs5xx - re-initialize device upon warm reset

The device may be inadvertently reset during runtime in the event
of ESD strike, etc. To protect against this case, acknowledge the
SHOW_RESET interrupt and re-initialize the device.

To facilitate this change, expand the range of registers that are
read in the interrupt handler to include the system status fields.

Also, update the unrelated (but nearby) SUSPEND register field to
use the BIT() macro. The remaining register fields are cleaned up
in another patch.

Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Link: https://lore.kernel.org/r/1611002626-5889-6-git-send-email-jeff@labundy.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/iqs5xx.c b/drivers/input/touchscreen/iqs5xx.c
index b2de8c67b5413085f681babc8696b6a12bb07647..cc84bcc3395b3d8264863a9e6af75b6ca38b86fa 100644 (file)
--- a/drivers/input/touchscreen/iqs5xx.c
+++ b/drivers/input/touchscreen/iqs5xx.c
@@ -11,6 +11,7 @@
  * Link to PC-based configuration tool and data sheet: http://www.azoteq.com/
  */
 
+#include <linux/bits.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
@@ -40,8 +41,11 @@
 #define IQS5XX_PROJ_NUM_B000   15
 #define IQS5XX_MAJOR_VER_MIN   2
 
-#define IQS5XX_RESUME          0x00
-#define IQS5XX_SUSPEND         0x01
+#define IQS5XX_SHOW_RESET      BIT(7)
+#define IQS5XX_ACK_RESET       BIT(7)
+
+#define IQS5XX_SUSPEND         BIT(0)
+#define IQS5XX_RESUME          0
 
 #define IQS5XX_SW_INPUT_EVENT  0x10
 #define IQS5XX_SETUP_COMPLETE  0x40
@@ -53,8 +57,8 @@
 #define IQS5XX_SWITCH_XY_AXIS  0x04
 
 #define IQS5XX_PROD_NUM                0x0000
-#define IQS5XX_ABS_X           0x0016
-#define IQS5XX_ABS_Y           0x0018
+#define IQS5XX_SYS_INFO0       0x000F
+#define IQS5XX_SYS_INFO1       0x0010
 #define IQS5XX_SYS_CTRL0       0x0431
 #define IQS5XX_SYS_CTRL1       0x0432
 #define IQS5XX_SYS_CFG0                0x058E
@@ -125,6 +129,14 @@ struct iqs5xx_touch_data {
        u8 area;
 } __packed;
 
+struct iqs5xx_status {
+       u8 sys_info[2];
+       u8 num_active;
+       __be16 rel_x;
+       __be16 rel_y;
+       struct iqs5xx_touch_data touch_data[IQS5XX_NUM_CONTACTS];
+} __packed;
+
 static int iqs5xx_read_burst(struct i2c_client *client,
                             u16 reg, void *val, u16 len)
 {
@@ -670,6 +682,10 @@ static int iqs5xx_dev_init(struct i2c_client *client)
        if (error)
                return error;
 
+       error = iqs5xx_write_byte(client, IQS5XX_SYS_CTRL0, IQS5XX_ACK_RESET);
+       if (error)
+               return error;
+
        error = iqs5xx_read_byte(client, IQS5XX_SYS_CFG0, &val);
        if (error)
                return error;
@@ -706,7 +722,7 @@ static int iqs5xx_dev_init(struct i2c_client *client)
 static irqreturn_t iqs5xx_irq(int irq, void *data)
 {
        struct iqs5xx_private *iqs5xx = data;
-       struct iqs5xx_touch_data touch_data[IQS5XX_NUM_CONTACTS];
+       struct iqs5xx_status status;
        struct i2c_client *client = iqs5xx->client;
        struct input_dev *input = iqs5xx->input;
        int error, i;
@@ -719,21 +735,35 @@ static irqreturn_t iqs5xx_irq(int irq, void *data)
        if (iqs5xx->bl_status == IQS5XX_BL_STATUS_RESET)
                return IRQ_NONE;
 
-       error = iqs5xx_read_burst(client, IQS5XX_ABS_X,
-                                 touch_data, sizeof(touch_data));
+       error = iqs5xx_read_burst(client, IQS5XX_SYS_INFO0,
+                                 &status, sizeof(status));
        if (error)
                return IRQ_NONE;
 
-       for (i = 0; i < ARRAY_SIZE(touch_data); i++) {
-               u16 pressure = be16_to_cpu(touch_data[i].strength);
+       if (status.sys_info[0] & IQS5XX_SHOW_RESET) {
+               dev_err(&client->dev, "Unexpected device reset\n");
+
+               error = iqs5xx_dev_init(client);
+               if (error) {
+                       dev_err(&client->dev,
+                               "Failed to re-initialize device: %d\n", error);
+                       return IRQ_NONE;
+               }
+
+               return IRQ_HANDLED;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(status.touch_data); i++) {
+               struct iqs5xx_touch_data *touch_data = &status.touch_data[i];
+               u16 pressure = be16_to_cpu(touch_data->strength);
 
                input_mt_slot(input, i);
                if (input_mt_report_slot_state(input, MT_TOOL_FINGER,
                                               pressure != 0)) {
                        input_report_abs(input, ABS_MT_POSITION_X,
-                                        be16_to_cpu(touch_data[i].abs_x));
+                                        be16_to_cpu(touch_data->abs_x));
                        input_report_abs(input, ABS_MT_POSITION_Y,
-                                        be16_to_cpu(touch_data[i].abs_y));
+                                        be16_to_cpu(touch_data->abs_y));
                        input_report_abs(input, ABS_MT_PRESSURE, pressure);
                }
        }