Input: atmel_mxt_ts - make wait-after-reset period compatible with all chips

The delay before the chip can be accessed after reset varies between
different chips in maXTouch family. Waiting for an interrupt and a T6
status message with the RESET bit set is a better behaviour.

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Acked-by: Benson Leung <bleung@chromium.org>
Acked-by: Yufeng Shen <miletus@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 87 insertions, 22 deletions

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index d5b30434c4ac..d3aef870d255 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -87,6 +87,9 @@
 #define MXT_COMMAND_REPORTALL   3
 #define MXT_COMMAND_DIAGNOSTIC  5
 
+/* Define for T6 status byte */
+#define MXT_T6_STATUS_RESET     (1 << 7)
+
 /* MXT_GEN_POWER_T7 field */
 #define MXT_POWER_IDLEACQINT    0
 #define MXT_POWER_ACTVACQINT    1
@@ -178,9 +181,13 @@
 
 /* Define for MXT_GEN_COMMAND_T6 */
 #define MXT_BOOT_VALUE          0xa5
+#define MXT_RESET_VALUE         0x01
 #define MXT_BACKUP_VALUE        0x55
+
+/* Delay times */
 #define MXT_BACKUP_TIME         50      /* msec */
 #define MXT_RESET_TIME          200     /* msec */
+#define MXT_RESET_TIMEOUT       3000    /* msec */
 #define MXT_FW_RESET_TIME       3000    /* msec */
 #define MXT_FW_CHG_TIMEOUT      300     /* msec */
 
@@ -255,12 +262,16 @@ struct mxt_data {
 
         /* Cached parameters from object table */
         u8 T6_reportid;
+        u16 T6_address;
         u8 T9_reportid_min;
         u8 T9_reportid_max;
         u8 T19_reportid;
 
         /* for fw update in bootloader */
         struct completion bl_completion;
+
+        /* for reset handling */
+        struct completion reset_completion;
 };
 
 static size_t mxt_obj_size(const struct mxt_object *obj)
@@ -344,10 +355,11 @@ static void mxt_dump_message(struct device *dev,
                 message->reportid, 7, message->message);
 }
 
-static int mxt_wait_for_chg(struct mxt_data *data, unsigned int timeout_ms)
+static int mxt_wait_for_completion(struct mxt_data *data,
+                                   struct completion *comp,
+                                   unsigned int timeout_ms)
 {
         struct device *dev = &data->client->dev;
-        struct completion *comp = &data->bl_completion;
         unsigned long timeout = msecs_to_jiffies(timeout_ms);
         long ret;
 
@@ -375,7 +387,8 @@ recheck:
                  * CHG assertion before reading the status byte.
                  * Once the status byte has been read, the line is deasserted.
                  */
-                ret = mxt_wait_for_chg(data, MXT_FW_CHG_TIMEOUT);
+                ret = mxt_wait_for_completion(data, &data->bl_completion,
+                                              MXT_FW_CHG_TIMEOUT);
                 if (ret) {
                         /*
                          * TODO: handle -ERESTARTSYS better by terminating
@@ -654,6 +667,9 @@ static irqreturn_t mxt_process_messages_until_invalid(struct mxt_data *data)
                         unsigned csum = mxt_extract_T6_csum(&payload[1]);
                         dev_dbg(dev, "Status: %02x Config Checksum: %06x\n",
                                 status, csum);
+
+                        if (status & MXT_T6_STATUS_RESET)
+                                complete(&data->reset_completion);
                 } else if (mxt_is_T9_message(data, &message)) {
                         int id = reportid - data->T9_reportid_min;
                         mxt_input_touchevent(data, &message, id);
@@ -687,6 +703,59 @@ static irqreturn_t mxt_interrupt(int irq, void *dev_id)
         return mxt_process_messages_until_invalid(data);
 }
 
+static int mxt_t6_command(struct mxt_data *data, u16 cmd_offset,
+                          u8 value, bool wait)
+{
+        u16 reg;
+        u8 command_register;
+        int timeout_counter = 0;
+        int ret;
+
+        reg = data->T6_address + cmd_offset;
+
+        ret = mxt_write_reg(data->client, reg, value);
+        if (ret)
+                return ret;
+
+        if (!wait)
+                return 0;
+
+        do {
+                msleep(20);
+                ret = __mxt_read_reg(data->client, reg, 1, &command_register);
+                if (ret)
+                        return ret;
+        } while (command_register != 0 && timeout_counter++ <= 100);
+
+        if (timeout_counter > 100) {
+                dev_err(&data->client->dev, "Command failed!\n");
+                return -EIO;
+        }
+
+        return 0;
+}
+
+static int mxt_soft_reset(struct mxt_data *data)
+{
+        struct device *dev = &data->client->dev;
+        int ret = 0;
+
+        dev_info(dev, "Resetting chip\n");
+
+        reinit_completion(&data->reset_completion);
+
+        ret = mxt_t6_command(data, MXT_COMMAND_RESET, MXT_RESET_VALUE, false);
+        if (ret)
+                return ret;
+
+        ret = mxt_wait_for_completion(data, &data->reset_completion,
+                                      MXT_RESET_TIMEOUT);
+        if (ret)
+                return ret;
+
+        return 0;
+}
+
 static int mxt_check_reg_init(struct mxt_data *data)
 {
         const struct mxt_platform_data *pdata = data->pdata;
@@ -800,6 +869,7 @@ static int mxt_get_object_table(struct mxt_data *data)
                 switch (object->type) {
                 case MXT_GEN_COMMAND_T6:
                         data->T6_reportid = min_id;
+                        data->T6_address = object->start_address;
                         break;
                 case MXT_TOUCH_MULTI_T9:
                         data->T9_reportid_min = min_id;
@@ -853,16 +923,10 @@ static int mxt_initialize(struct mxt_data *data)
         if (error)
                 goto err_free_object_table;
 
-        /* Backup to memory */
-        mxt_write_object(data, MXT_GEN_COMMAND_T6,
-                        MXT_COMMAND_BACKUPNV,
-                        MXT_BACKUP_VALUE);
-        msleep(MXT_BACKUP_TIME);
-
-        /* Soft reset */
-        mxt_write_object(data, MXT_GEN_COMMAND_T6,
-                        MXT_COMMAND_RESET, 1);
-        msleep(MXT_RESET_TIME);
+        error = mxt_t6_command(data, MXT_COMMAND_BACKUPNV,
+                               MXT_BACKUP_VALUE, false);
+        if (!error)
+                mxt_soft_reset(data);
 
         /* Update matrix size at info struct */
         error = mxt_read_reg(client, MXT_MATRIX_X_SIZE, &val);
@@ -1004,8 +1068,10 @@ static int mxt_load_fw(struct device *dev, const char *fn)
         /* Change to the bootloader mode */
         data->in_bootloader = true;
 
-        mxt_write_object(data, MXT_GEN_COMMAND_T6,
-                        MXT_COMMAND_RESET, MXT_BOOT_VALUE);
+        ret = mxt_t6_command(data, MXT_COMMAND_RESET, MXT_BOOT_VALUE, false);
+        if (ret)
+                goto release_firmware;
+
         msleep(MXT_RESET_TIME);
 
         /* Change to slave address of bootloader */
@@ -1048,7 +1114,8 @@ static int mxt_load_fw(struct device *dev, const char *fn)
         }
 
         /* Wait for flash. */
-        ret = mxt_wait_for_chg(data, MXT_FW_RESET_TIME);
+        ret = mxt_wait_for_completion(data, &data->bl_completion,
+                                      MXT_FW_RESET_TIME);
         if (ret)
                 goto disable_irq;
 
@@ -1057,12 +1124,13 @@ static int mxt_load_fw(struct device *dev, const char *fn)
          * the CHG line after bootloading has finished, so ignore potential
          * errors.
          */
-        mxt_wait_for_chg(data, MXT_FW_RESET_TIME);
+        mxt_wait_for_completion(data, &data->bl_completion, MXT_FW_RESET_TIME);
 
         data->in_bootloader = false;
 
 disable_irq:
         disable_irq(data->irq);
+release_firmware:
         release_firmware(fw);
 
         /* Change to slave address of application */
@@ -1187,6 +1255,7 @@ static int mxt_probe(struct i2c_client *client,
         data->irq = client->irq;
 
         init_completion(&data->bl_completion);
+        init_completion(&data->reset_completion);
 
         mxt_calc_resolution(data);
 
@@ -1314,11 +1383,7 @@ static int mxt_resume(struct device *dev)
         struct mxt_data *data = i2c_get_clientdata(client);
         struct input_dev *input_dev = data->input_dev;
 
-        /* Soft reset */
-        mxt_write_object(data, MXT_GEN_COMMAND_T6,
-                        MXT_COMMAND_RESET, 1);
-
-        msleep(MXT_RESET_TIME);
+        mxt_soft_reset(data);
 
         mutex_lock(&input_dev->mutex);