From: Nick Dyer <nick.d...@itdev.co.uk>

Implement improved debug message interface

Signed-off-by: Nick Dyer <nick.d...@itdev.co.uk>
(cherry picked from ndyer/linux/for-upstream commit 
078569c13c88dcb6f8d882bfe17168587712df7d)
[gdavis: Resolve forward port conflicts due to v4.14.51 commit
         960fe000b1d3 ("Input: atmel_mxt_ts - fix the firmware
         update").]
Signed-off-by: George G. Davis <george_da...@mentor.com>
[gdavis: Squash fixes from Dirk Behme:
         - Input: atmel_mxt_ts - add missing unlock in error path
         - Input: atmel_mxt_ts - add missing unlock in error path
         - Input: atmel_mxt_ts - call mxt_debug_msg_remove() in error path
         - Input: atmel_mxt_ts - protect debug_v2_enabled by mutex
Signed-off-by: Dirk Behme <dirk.be...@de.bosch.com>
[gdavis: Squash fix from Vladimir Zapolskiy:
         - Input: atmel_mxt_ts - simplify debug_msg binary attribute
           handling]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapols...@mentor.com>
[jiada: Rename mxt_debug_notify_show to debug_notify_show
        Rename mxt_debug_v2_enable_store to debug_v2_enable_store
        Add debug_v2_enable_show
        Replace DEVICE_ATTR with DEVICE_ATTR_[RW|RO] ]
Signed-off-by: Jiada Wang <jiada_w...@mentor.com>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 201 ++++++++++++++++++++++-
 1 file changed, 200 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c 
b/drivers/input/touchscreen/atmel_mxt_ts.c
index 7d48c4d1f57d..92c883087a4f 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -243,6 +243,8 @@ enum t100_type {
 
 #define MXT_PIXELS_PER_MM      20
 
+#define DEBUG_MSG_MAX          200
+
 struct mxt_info {
        u8 family_id;
        u8 variant_id;
@@ -337,6 +339,11 @@ struct mxt_data {
        u8 t100_aux_area;
        u8 t100_aux_vect;
        bool debug_enabled;
+       bool debug_v2_enabled;
+       u8 *debug_msg_data;
+       u16 debug_msg_count;
+       struct bin_attribute *debug_msg_attr;
+       struct mutex debug_msg_lock;
        u8 max_reportid;
        u32 config_crc;
        u32 info_crc;
@@ -469,6 +476,144 @@ static void mxt_dump_message(struct mxt_data *data, u8 
*message)
                       data->T5_msg_size, message);
 }
 
+static void mxt_debug_msg_enable(struct mxt_data *data)
+{
+       struct device *dev = &data->client->dev;
+
+       if (data->debug_v2_enabled)
+               return;
+
+       mutex_lock(&data->debug_msg_lock);
+
+       data->debug_msg_data = kcalloc(DEBUG_MSG_MAX,
+                               data->T5_msg_size, GFP_KERNEL);
+       if (!data->debug_msg_data) {
+               mutex_unlock(&data->debug_msg_lock);
+               return;
+       }
+
+       data->debug_v2_enabled = true;
+       mutex_unlock(&data->debug_msg_lock);
+
+       dev_dbg(dev, "Enabled message output\n");
+}
+
+static void mxt_debug_msg_disable(struct mxt_data *data)
+{
+       struct device *dev = &data->client->dev;
+
+       if (!data->debug_v2_enabled)
+               return;
+
+       mutex_lock(&data->debug_msg_lock);
+
+       data->debug_v2_enabled = false;
+
+       kfree(data->debug_msg_data);
+       data->debug_msg_data = NULL;
+       data->debug_msg_count = 0;
+       mutex_unlock(&data->debug_msg_lock);
+       dev_dbg(dev, "Disabled message output\n");
+}
+
+static void mxt_debug_msg_add(struct mxt_data *data, u8 *msg)
+{
+       struct device *dev = &data->client->dev;
+
+       mutex_lock(&data->debug_msg_lock);
+
+       if (!data->debug_msg_data) {
+               mutex_unlock(&data->debug_msg_lock);
+               dev_err(dev, "No buffer!\n");
+               return;
+       }
+
+       if (data->debug_msg_count < DEBUG_MSG_MAX) {
+               memcpy(data->debug_msg_data +
+                      data->debug_msg_count * data->T5_msg_size,
+                      msg,
+                      data->T5_msg_size);
+               data->debug_msg_count++;
+       } else {
+               dev_dbg(dev, "Discarding %u messages\n", data->debug_msg_count);
+               data->debug_msg_count = 0;
+       }
+
+       mutex_unlock(&data->debug_msg_lock);
+
+       sysfs_notify(&data->client->dev.kobj, NULL, "debug_notify");
+}
+
+static ssize_t mxt_debug_msg_read(struct file *filp, struct kobject *kobj,
+       struct bin_attribute *bin_attr, char *buf, loff_t off, size_t bytes)
+{
+       struct device *dev = container_of(kobj, struct device, kobj);
+       struct mxt_data *data = dev_get_drvdata(dev);
+       int count;
+       size_t bytes_read;
+
+       if (!data->debug_msg_data) {
+               dev_err(dev, "No buffer!\n");
+               return 0;
+       }
+
+       count = bytes / data->T5_msg_size;
+
+       if (count > DEBUG_MSG_MAX)
+               count = DEBUG_MSG_MAX;
+
+       mutex_lock(&data->debug_msg_lock);
+
+       if (count > data->debug_msg_count)
+               count = data->debug_msg_count;
+
+       bytes_read = count * data->T5_msg_size;
+
+       memcpy(buf, data->debug_msg_data, bytes_read);
+       data->debug_msg_count = 0;
+
+       mutex_unlock(&data->debug_msg_lock);
+
+       return bytes_read;
+}
+
+static struct bin_attribute debug_msg_attr = {
+       .attr = {
+               .name = "debug_msg",
+               .mode = 0444,
+       },
+       .read = mxt_debug_msg_read,
+};
+
+static int mxt_debug_msg_init(struct mxt_data *data)
+{
+       /*
+        * Binary attribute is not used in callback, removal is done by name,
+        * so it is safe to update a single struct bin_attribute entity
+        */
+       debug_msg_attr.size = data->T5_msg_size * DEBUG_MSG_MAX;
+
+       if (sysfs_create_bin_file(&data->client->dev.kobj,
+                                 &debug_msg_attr) < 0) {
+               dev_err(&data->client->dev, "Failed to create %s\n",
+                       debug_msg_attr.attr.name);
+               return -EINVAL;
+       }
+
+       data->debug_msg_attr = &debug_msg_attr;
+
+       return 0;
+}
+
+static void mxt_debug_msg_remove(struct mxt_data *data)
+{
+       if (data->debug_msg_attr) {
+               sysfs_remove_bin_file(&data->client->dev.kobj,
+                                     data->debug_msg_attr);
+               data->debug_msg_attr = NULL;
+       }
+}
+
 static int mxt_wait_for_completion(struct mxt_data *data,
                                   struct completion *comp,
                                   unsigned int timeout_ms)
@@ -1257,6 +1402,9 @@ static int mxt_proc_message(struct mxt_data *data, u8 
*message)
        if (dump)
                mxt_dump_message(data, message);
 
+       if (data->debug_v2_enabled)
+               mxt_debug_msg_add(data, message);
+
        return 1;
 }
 
@@ -2660,6 +2808,10 @@ static int mxt_initialize(struct mxt_data *data)
        if (error)
                return error;
 
+       error = mxt_debug_msg_init(data);
+       if (error)
+               goto err_free_sysfs;
+
        error = request_firmware_nowait(THIS_MODULE, true,
                                        data->cfg_name ?
                                        data->cfg_name : MXT_CFG_NAME,
@@ -2669,11 +2821,13 @@ static int mxt_initialize(struct mxt_data *data)
        if (error) {
                dev_err(&client->dev, "Failed to invoke firmware loader: %d\n",
                        error);
-               goto err_free_sysfs;
+               goto err_free_dbg_msg;
        }
 
        return 0;
 
+err_free_dbg_msg:
+       mxt_debug_msg_remove(data);
 err_free_sysfs:
        mxt_sysfs_remove(data);
        return error;
@@ -3335,6 +3489,7 @@ static int mxt_enter_bootloader(struct mxt_data *data)
                        return ret;
 
                data->in_bootloader = true;
+               mxt_debug_msg_remove(data);
                mxt_sysfs_remove(data);
                mxt_free_input_device(data);
                mxt_free_object_table(data);
@@ -3506,6 +3661,44 @@ static ssize_t update_cfg_store(struct device *dev,
        return ret;
 }
 
+static ssize_t debug_notify_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       return sprintf(buf, "0\n");
+}
+
+static ssize_t debug_v2_enable_store(struct device *dev,
+       struct device_attribute *attr, const char *buf, size_t count)
+{
+       struct mxt_data *data = dev_get_drvdata(dev);
+       u8 i;
+       ssize_t ret;
+
+       if (kstrtou8(buf, 0, &i) == 0 && i < 2) {
+               if (i == 1)
+                       mxt_debug_msg_enable(data);
+               else
+                       mxt_debug_msg_disable(data);
+
+               ret = count;
+       } else {
+               dev_dbg(dev, "debug_enabled write error\n");
+               ret = -EINVAL;
+       }
+
+       return ret;
+}
+
+static ssize_t debug_v2_enable_show(struct device *dev,
+       struct device_attribute *attr, char *buf)
+{
+       struct mxt_data *data = dev_get_drvdata(dev);
+       char c;
+
+       c = data->debug_v2_enabled ? '1' : '0';
+       return scnprintf(buf, PAGE_SIZE, "%c\n", c);
+}
+
 static ssize_t debug_enable_show(struct device *dev,
        struct device_attribute *attr, char *buf)
 {
@@ -3553,6 +3746,8 @@ static DEVICE_ATTR_RO(object);
 static DEVICE_ATTR_WO(update_cfg);
 static DEVICE_ATTR_RO(config_crc);
 static DEVICE_ATTR_RW(debug_enable);
+static DEVICE_ATTR_RW(debug_v2_enable);
+static DEVICE_ATTR_RO(debug_notify);
 
 static struct attribute *mxt_attrs[] = {
        &dev_attr_fw_version.attr,
@@ -3561,6 +3756,8 @@ static struct attribute *mxt_attrs[] = {
        &dev_attr_update_cfg.attr,
        &dev_attr_config_crc.attr,
        &dev_attr_debug_enable.attr,
+       &dev_attr_debug_v2_enable.attr,
+       &dev_attr_debug_notify.attr,
        NULL
 };
 
@@ -3851,6 +4048,7 @@ static int mxt_probe(struct i2c_client *client, const 
struct i2c_device_id *id)
        init_completion(&data->chg_completion);
        init_completion(&data->reset_completion);
        init_completion(&data->crc_completion);
+       mutex_init(&data->debug_msg_lock);
 
        data->suspend_mode = dmi_check_system(chromebook_T9_suspend_dmi) ?
                MXT_SUSPEND_T9_CTRL : MXT_SUSPEND_DEEP_SLEEP;
@@ -3916,6 +4114,7 @@ static int mxt_remove(struct i2c_client *client)
 
        disable_irq(data->irq);
        sysfs_remove_group(&client->dev.kobj, &mxt_fw_attr_group);
+       mxt_debug_msg_remove(data);
        mxt_sysfs_remove(data);
        mxt_free_input_device(data);
        mxt_free_object_table(data);
-- 
2.17.1

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