From: Iiro Valkonen <iiro.valko...@atmel.com>

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.d...@itdev.co.uk>
Acked-by: Benson Leung <ble...@chromium.org>
---
 drivers/input/touchscreen/atmel_mxt_ts.c |  109 ++++++++++++++++++++++++------
 1 file changed, 87 insertions(+), 22 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c 
b/drivers/input/touchscreen/atmel_mxt_ts.c
index 1e24e54..11ee78a 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -88,6 +88,9 @@
 #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
@@ -179,9 +182,13 @@
 
 /* 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 */
 
@@ -256,6 +263,7 @@ 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;
@@ -263,6 +271,9 @@ struct mxt_data {
        /* for fw update in bootloader */
        struct completion bl_completion;
 
+       /* for reset handling */
+       struct completion reset_completion;
+
        /* Enable reporting of input events */
        bool enable_reporting;
 };
@@ -348,10 +359,10 @@ 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;
 
@@ -380,7 +391,8 @@ 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 -EINTR better by terminating fw update
@@ -667,6 +679,9 @@ 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);
@@ -703,6 +718,59 @@ 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");
+
+       INIT_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;
@@ -829,6 +897,7 @@ 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;
@@ -887,16 +956,10 @@ 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);
@@ -1040,8 +1103,10 @@ 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 */
@@ -1084,18 +1149,21 @@ 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;
 
        /* Wait for device to reset. Some bootloader versions do not assert
         * the CHG line after bootloading has finished, so ignore error */
-       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 */
@@ -1216,6 +1284,7 @@ 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);
 
@@ -1341,11 +1410,7 @@ 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);
 
-- 
1.7.10.4

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