Goodix devices can be configured by writing this information
to the device at init. The configuration data can
be provided through the ACPI/device tree property
"device-config". If "device-config" is not set, the default
device configuration will be used.

Signed-off-by: Octavian Purdila <octavian.purd...@intel.com>
Signed-off-by: Irina Tirdea <irina.tir...@intel.com>
---
 .../bindings/input/touchscreen/goodix.txt          |   5 +
 drivers/input/touchscreen/goodix.c                 | 143 +++++++++++++++++++++
 2 files changed, 148 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt 
b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
index 7137881..9e4ff69 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
@@ -15,6 +15,11 @@ Required properties:
  - irq-gpio            : GPIO pin used for IRQ
  - reset-gpio          : GPIO pin used for reset
 
+Optional properties:
+
+ - device-config       : device configuration information (specified as byte
+                         array). Maximum size is 240 bytes.
+
 Example:
 
        i2c@00000000 {
diff --git a/drivers/input/touchscreen/goodix.c 
b/drivers/input/touchscreen/goodix.c
index 4405c55..22052c9 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -41,6 +41,8 @@ struct goodix_ts_data {
 
 #define GOODIX_GPIO_INT_NAME           "irq"
 #define GOODIX_GPIO_RST_NAME           "reset"
+#define GOODIX_DEVICE_CONFIG_PROPERTY  "device-config"
+
 #define GOODIX_MAX_HEIGHT              4096
 #define GOODIX_MAX_WIDTH               4096
 #define GOODIX_INT_TRIGGER             1
@@ -94,6 +96,39 @@ static int goodix_i2c_read(struct i2c_client *client,
        return ret < 0 ? ret : (ret != ARRAY_SIZE(msgs) ? -EIO : 0);
 }
 
+/**
+ * goodix_i2c_write - write data to a register of the i2c slave device.
+ *
+ * @client: i2c device.
+ * @reg: the register to write to.
+ * @buf: raw data buffer to write.
+ * @len: length of the buffer to write
+ */
+static int goodix_i2c_write(struct i2c_client *client, u16 reg, u8 *buf,
+                           unsigned len)
+{
+       u8 *addr_buf;
+       struct i2c_msg msg;
+       int ret;
+
+       addr_buf = kmalloc(len + 2, GFP_KERNEL);
+       if (!addr_buf)
+               return -ENOMEM;
+
+       addr_buf[0] = reg >> 8;
+       addr_buf[1] = reg & 0xFF;
+       memcpy(&addr_buf[2], buf, len);
+
+       msg.flags = 0;
+       msg.addr = client->addr;
+       msg.buf = addr_buf;
+       msg.len = len + 2;
+
+       ret = i2c_transfer(client->adapter, &msg, 1);
+       kfree(addr_buf);
+       return ret < 0 ? ret : (ret != 1 ? -EIO : 0);
+}
+
 static int goodix_ts_read_input_report(struct goodix_ts_data *ts, u8 *data)
 {
        int touch_num;
@@ -192,6 +227,109 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void 
*dev_id)
        return IRQ_HANDLED;
 }
 
+/**
+ * goodix_get_cfg - Get device config from ACPI/DT.
+ *
+ * @ts: goodix_ts_data pointer
+ * @config: pointer to the config buffer
+ * @cfg_len: pointer to size of the config buffer
+ */
+static int goodix_get_cfg(struct goodix_ts_data *ts, u8 **config, int *cfg_len)
+{
+       int ret, i, raw_cfg_len;
+       u8 check_sum = 0;
+
+       ret = device_property_read_u8_array(&ts->client->dev,
+                                           GOODIX_DEVICE_CONFIG_PROPERTY,
+                                           NULL, 0);
+       if (ret <= 0) {
+               dev_err(&ts->client->dev, "No %s property.\n",
+                       GOODIX_DEVICE_CONFIG_PROPERTY);
+               return 0;
+       }
+
+       *cfg_len = ret;
+       if (*cfg_len > GOODIX_CONFIG_MAX_LENGTH) {
+               dev_err(&ts->client->dev,
+                       "The length of the config buffer array is not correct");
+               return -EINVAL;
+       }
+
+       *config = kmalloc(*cfg_len, GFP_KERNEL);
+       if (!*config)
+               return -ENOMEM;
+
+       ret = device_property_read_u8_array(&ts->client->dev,
+                                           GOODIX_DEVICE_CONFIG_PROPERTY,
+                                           *config, *cfg_len);
+       if (ret < 0) {
+               dev_err(&ts->client->dev, "Invalid %s property: %d\n",
+                       GOODIX_DEVICE_CONFIG_PROPERTY, ret);
+               goto err_free;
+       }
+
+       raw_cfg_len = *cfg_len - 2;
+       for (i = 0; i < raw_cfg_len; i++)
+               check_sum += (*config)[i];
+       check_sum = (~check_sum) + 1;
+       if (check_sum != (*config)[raw_cfg_len]) {
+               dev_err(&ts->client->dev,
+                       "The checksum of the config buffer array is not 
correct");
+               ret = -EINVAL;
+               goto err_free;
+       }
+       if ((*config)[raw_cfg_len + 1] != 1) {
+               dev_err(&ts->client->dev,
+                       "The Config_Fresh register needs to be set");
+               ret = -EINVAL;
+               goto err_free;
+       }
+
+       return 0;
+
+err_free:
+       kfree(*config);
+       return ret;
+}
+
+/**
+ * goodix_send_cfg - Write device config
+ *
+ * @ts: goodix_ts_data pointer
+ */
+static int goodix_send_cfg(struct goodix_ts_data *ts)
+{
+       int ret, cfg_len = 0;
+       u8 *config = NULL;
+
+       ret = goodix_get_cfg(ts, &config, &cfg_len);
+       if (ret)
+               return ret;
+
+       /* No config property in device tree */
+       if (!cfg_len)
+               return 0;
+
+       ret = goodix_i2c_write(ts->client, GOODIX_REG_CONFIG_DATA, config,
+                              cfg_len);
+       if (ret) {
+               dev_err(&ts->client->dev, "Failed to send the config : %d",
+                       ret);
+               goto err_free;
+       }
+       dev_dbg(&ts->client->dev, "Config sent successfully.");
+
+       /* Let the firmware reconfigure itself, so sleep for 10ms */
+       usleep_range(10000, 11000);
+
+       kfree(config);
+       return 0;
+
+err_free:
+       kfree(config);
+       return ret;
+}
+
 static int goodix_int_sync(struct goodix_ts_data *ts)
 {
        int ret;
@@ -465,6 +603,11 @@ static int goodix_ts_probe(struct i2c_client *client,
                return error;
        }
 
+       /* send device configuration to the firmware */
+       error = goodix_send_cfg(ts);
+       if (error)
+               return error;
+
        goodix_read_config(ts);
 
        error = goodix_request_input_dev(ts, version_info, id_info);
-- 
1.9.1

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