#include <linux/regulator/consumer.h>
 
 /* Register defines */
+#define GOODIX_REG_MISCTL_DSP_CTL              0x4010
+#define GOODIX_REG_MISCTL_SRAM_BANK            0x4048
+#define GOODIX_REG_MISCTL_MEM_CD_EN            0x4049
+#define GOODIX_REG_MISCTL_CACHE_EN             0x404B
+#define GOODIX_REG_MISCTL_TMR0_EN              0x40B0
+#define GOODIX_REG_MISCTL_SWRST                        0x4180
+#define GOODIX_REG_MISCTL_CPU_SWRST_PULSE      0x4184
+#define GOODIX_REG_MISCTL_BOOTCTL              0x4190
+#define GOODIX_REG_MISCTL_BOOT_OPT             0x4218
+#define GOODIX_REG_MISCTL_BOOT_CTL             0x5094
+
+#define GOODIX_REG_FW_SIG                      0x8000
+#define GOODIX_FW_SIG_LEN                      10
+
+#define GOODIX_REG_MAIN_CLK                    0x8020
+#define GOODIX_MAIN_CLK_LEN                    6
+
 #define GOODIX_REG_COMMAND                     0x8040
 #define GOODIX_CMD_SCREEN_OFF                  0x05
 
+#define GOODIX_REG_SW_WDT                      0x8041
+
+#define GOODIX_REG_REQUEST                     0x8043
+#define GOODIX_RQST_RESPONDED                  0x00
+#define GOODIX_RQST_CONFIG                     0x01
+#define GOODIX_RQST_BAK_REF                    0x02
+#define GOODIX_RQST_RESET                      0x03
+#define GOODIX_RQST_MAIN_CLOCK                 0x04
+/*
+ * Unknown request which gets send by the controller aprox.
+ * every 34 seconds once it is up and running.
+ */
+#define GOODIX_RQST_UNKNOWN                    0x06
+#define GOODIX_RQST_IDLE                       0xFF
+
+#define GOODIX_REG_STATUS                      0x8044
+
 #define GOODIX_GT1X_REG_CONFIG_DATA            0x8050
 #define GOODIX_GT9X_REG_CONFIG_DATA            0x8047
 #define GOODIX_REG_ID                          0x8140
 #define GOODIX_READ_COOR_ADDR                  0x814E
+#define GOODIX_REG_BAK_REF                     0x99D0
 
 #define GOODIX_ID_MAX_LEN                      4
 #define GOODIX_CONFIG_MAX_LENGTH               240
        struct i2c_client *client;
        struct input_dev *input_dev;
        const struct goodix_chip_data *chip;
+       const char *firmware_name;
        struct touchscreen_properties prop;
        unsigned int max_touch_num;
        unsigned int int_trigger_type;
        unsigned int contact_size;
        u8 config[GOODIX_CONFIG_MAX_LENGTH];
        unsigned short keymap[GOODIX_MAX_KEYS];
+       u8 main_clk[GOODIX_MAIN_CLK_LEN];
+       int bak_ref_len;
+       u8 *bak_ref;
 };
 
 int goodix_i2c_read(struct i2c_client *client, u16 reg, u8 *buf, int len);
 int goodix_int_sync(struct goodix_ts_data *ts);
 int goodix_reset_no_int_sync(struct goodix_ts_data *ts);
 
+int goodix_firmware_check(struct goodix_ts_data *ts);
+bool goodix_handle_fw_request(struct goodix_ts_data *ts);
+void goodix_save_bak_ref(struct goodix_ts_data *ts);
+
 #endif
 
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Goodix Touchscreen firmware upload support
+ *
+ * Copyright (c) 2021 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This is a rewrite of gt9xx_update.c from the Allwinner H3 BSP which is:
+ * Copyright (c) 2010 - 2012 Goodix Technology.
+ * Author: andrew@goodix.com
+ */
+
+#include <linux/device.h>
+#include <linux/firmware.h>
+#include <linux/i2c.h>
+#include "goodix.h"
+
+#define GOODIX_FW_HEADER_LENGTH                sizeof(struct goodix_fw_header)
+#define GOODIX_FW_SECTION_LENGTH       0x2000
+#define GOODIX_FW_DSP_LENGTH           0x1000
+#define GOODIX_FW_UPLOAD_ADDRESS       0xc000
+
+#define GOODIX_CFG_LOC_HAVE_KEY                 7
+#define GOODIX_CFG_LOC_DRVA_NUM                27
+#define GOODIX_CFG_LOC_DRVB_NUM                28
+#define GOODIX_CFG_LOC_SENS_NUM                29
+
+struct goodix_fw_header {
+       u8 hw_info[4];
+       u8 pid[8];
+       u8 vid[2];
+} __packed;
+
+static u16 goodix_firmware_checksum(const u8 *data, int size)
+{
+       u16 checksum = 0;
+       int i;
+
+       for (i = 0; i < size; i += 2)
+               checksum += (data[i] << 8) + data[i + 1];
+
+       return checksum;
+}
+
+static int goodix_firmware_verify(struct device *dev, const struct firmware *fw)
+{
+       const struct goodix_fw_header *fw_header;
+       size_t expected_size;
+       const u8 *data;
+       u16 checksum;
+       char buf[9];
+
+       expected_size = GOODIX_FW_HEADER_LENGTH + 4 * GOODIX_FW_SECTION_LENGTH +
+                       GOODIX_FW_DSP_LENGTH;
+       if (fw->size != expected_size) {
+               dev_err(dev, "Firmware has wrong size, expected %zu got %zu\n",
+                       expected_size, fw->size);
+               return -EINVAL;
+       }
+
+       data = fw->data + GOODIX_FW_HEADER_LENGTH;
+       checksum = goodix_firmware_checksum(data, 4 * GOODIX_FW_SECTION_LENGTH);
+       if (checksum) {
+               dev_err(dev, "Main firmware checksum error\n");
+               return -EINVAL;
+       }
+
+       data += 4 * GOODIX_FW_SECTION_LENGTH;
+       checksum = goodix_firmware_checksum(data, GOODIX_FW_DSP_LENGTH);
+       if (checksum) {
+               dev_err(dev, "DSP firmware checksum error\n");
+               return -EINVAL;
+       }
+
+       fw_header = (const struct goodix_fw_header *)fw->data;
+       dev_info(dev, "Firmware hardware info %02x%02x%02x%02x\n",
+                fw_header->hw_info[0], fw_header->hw_info[1],
+                fw_header->hw_info[2], fw_header->hw_info[3]);
+       /* pid is a 8 byte buffer containing a string, weird I know */
+       memcpy(buf, fw_header->pid, 8);
+       buf[8] = 0;
+       dev_info(dev, "Firmware PID: %s VID: %02x%02x\n", buf,
+                fw_header->vid[0], fw_header->vid[1]);
+       return 0;
+}
+
+static int goodix_enter_upload_mode(struct i2c_client *client)
+{
+       int tries, error;
+       u8 val;
+
+       tries = 200;
+       do {
+               error = goodix_i2c_write_u8(client,
+                                           GOODIX_REG_MISCTL_SWRST, 0x0c);
+               if (error)
+                       return error;
+
+               error = goodix_i2c_read(client,
+                                       GOODIX_REG_MISCTL_SWRST, &val, 1);
+               if (error)
+                       return error;
+
+               if (val == 0x0c)
+                       break;
+       } while (--tries);
+
+       if (!tries) {
+               dev_err(&client->dev, "Error could not hold ss51 & dsp\n");
+               return -EIO;
+       }
+
+       /* DSP_CK and DSP_ALU_CK PowerOn */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_DSP_CTL, 0x00);
+       if (error)
+               return error;
+
+       /* Disable watchdog */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_TMR0_EN, 0x00);
+       if (error)
+               return error;
+
+       /* Clear cache enable */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_CACHE_EN, 0x00);
+       if (error)
+               return error;
+
+       /* Set boot from SRAM */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_BOOTCTL, 0x02);
+       if (error)
+               return error;
+
+       /* Software reboot */
+       error = goodix_i2c_write_u8(client,
+                                   GOODIX_REG_MISCTL_CPU_SWRST_PULSE, 0x01);
+       if (error)
+               return error;
+
+       /* Clear control flag */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_BOOTCTL, 0x00);
+       if (error)
+               return error;
+
+       /* Set scramble */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_BOOT_OPT, 0x00);
+       if (error)
+               return error;
+
+       /* Enable accessing code */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_MEM_CD_EN, 0x01);
+       if (error)
+               return error;
+
+       return 0;
+}
+
+static int goodix_start_firmware(struct i2c_client *client)
+{
+       int error;
+       u8 val;
+
+       /* Init software watchdog */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_SW_WDT, 0xaa);
+       if (error)
+               return error;
+
+       /* Release SS51 & DSP */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_MISCTL_SWRST, 0x00);
+       if (error)
+               return error;
+
+       error = goodix_i2c_read(client, GOODIX_REG_SW_WDT, &val, 1);
+       if (error)
+               return error;
+
+       /* The value we've written to SW_WDT should have been cleared now */
+       if (val == 0xaa) {
+               dev_err(&client->dev, "Error SW_WDT reg not cleared on fw startup\n");
+               return -EIO;
+       }
+
+       /* Re-init software watchdog */
+       error = goodix_i2c_write_u8(client, GOODIX_REG_SW_WDT, 0xaa);
+       if (error)
+               return error;
+
+       return 0;
+}
+
+static int goodix_firmware_upload(struct goodix_ts_data *ts)
+{
+       const struct firmware *fw;
+       char fw_name[64];
+       const u8 *data;
+       int error;
+
+       snprintf(fw_name, sizeof(fw_name), "goodix/%s", ts->firmware_name);
+
+       error = request_firmware(&fw, fw_name, &ts->client->dev);
+       if (error) {
+               dev_err(&ts->client->dev, "Firmware request error %d\n", error);
+               return error;
+       }
+
+       error = goodix_firmware_verify(&ts->client->dev, fw);
+       if (error)
+               goto release;
+
+       error = goodix_reset_no_int_sync(ts);
+       if (error)
+               return error;
+
+       error = goodix_enter_upload_mode(ts->client);
+       if (error)
+               goto release;
+
+       /* Select SRAM bank 0 and upload section 1 & 2 */
+       error = goodix_i2c_write_u8(ts->client,
+                                   GOODIX_REG_MISCTL_SRAM_BANK, 0x00);
+       if (error)
+               goto release;
+
+       data = fw->data + GOODIX_FW_HEADER_LENGTH;
+       error = goodix_i2c_write(ts->client, GOODIX_FW_UPLOAD_ADDRESS,
+                                data, 2 * GOODIX_FW_SECTION_LENGTH);
+       if (error)
+               goto release;
+
+       /* Select SRAM bank 1 and upload section 3 & 4 */
+       error = goodix_i2c_write_u8(ts->client,
+                                   GOODIX_REG_MISCTL_SRAM_BANK, 0x01);
+       if (error)
+               goto release;
+
+       data += 2 * GOODIX_FW_SECTION_LENGTH;
+       error = goodix_i2c_write(ts->client, GOODIX_FW_UPLOAD_ADDRESS,
+                                data, 2 * GOODIX_FW_SECTION_LENGTH);
+       if (error)
+               goto release;
+
+       /* Select SRAM bank 2 and upload the DSP firmware */
+       error = goodix_i2c_write_u8(ts->client,
+                                   GOODIX_REG_MISCTL_SRAM_BANK, 0x02);
+       if (error)
+               goto release;
+
+       data += 2 * GOODIX_FW_SECTION_LENGTH;
+       error = goodix_i2c_write(ts->client, GOODIX_FW_UPLOAD_ADDRESS,
+                                data, GOODIX_FW_DSP_LENGTH);
+       if (error)
+               goto release;
+
+       error = goodix_start_firmware(ts->client);
+       if (error)
+               goto release;
+
+       error = goodix_int_sync(ts);
+release:
+       release_firmware(fw);
+       return error;
+}
+
+static int goodix_prepare_bak_ref(struct goodix_ts_data *ts)
+{
+       u8 have_key, driver_num, sensor_num;
+
+       if (ts->bak_ref)
+               return 0; /* Already done */
+
+       have_key = (ts->config[GOODIX_CFG_LOC_HAVE_KEY] & 0x01);
+
+       driver_num = (ts->config[GOODIX_CFG_LOC_DRVA_NUM] & 0x1f) +
+                    (ts->config[GOODIX_CFG_LOC_DRVB_NUM] & 0x1f);
+       if (have_key)
+               driver_num--;
+
+       sensor_num = (ts->config[GOODIX_CFG_LOC_SENS_NUM] & 0x0f) +
+                    ((ts->config[GOODIX_CFG_LOC_SENS_NUM] >> 4) & 0x0f);
+
+       dev_dbg(&ts->client->dev, "Drv %d Sen %d Key %d\n",
+               driver_num, sensor_num, have_key);
+
+       ts->bak_ref_len = (driver_num * (sensor_num - 2) + 2) * 2;
+
+       ts->bak_ref = devm_kzalloc(&ts->client->dev,
+                                  ts->bak_ref_len, GFP_KERNEL);
+       if (!ts->bak_ref)
+               return -ENOMEM;
+
+       /*
+        * The bak_ref array contains the backup of an array of (self/auto)
+        * calibration related values which the Android version of the driver
+        * stores on the filesystem so that it can be restored after reboot.
+        * The mainline kernel never writes directly to the filesystem like
+        * this, we always start will all the values which give a correction
+        * factor in approx. the -20 - +20 range (in 2s complement) set to 0.
+        *
+        * Note the touchscreen works fine without restoring the reference
+        * values after a reboot / power-cycle.
+        *
+        * The last 2 bytes are a 16 bits unsigned checksum which is expected
+        * to make the addition al all 16 bit unsigned values in the array add
+        * up to 1 (rather then the usual 0), so we must set the last byte to 1.
+        */
+       ts->bak_ref[ts->bak_ref_len - 1] = 1;
+
+       return 0;
+}
+
+static int goodix_send_main_clock(struct goodix_ts_data *ts)
+{
+       u32 main_clk = 54; /* Default main clock */
+       u8 checksum = 0;
+       int i;
+
+       device_property_read_u32(&ts->client->dev,
+                                "goodix,main-clk", &main_clk);
+
+       for (i = 0; i < (GOODIX_MAIN_CLK_LEN - 1); i++) {
+               ts->main_clk[i] = main_clk;
+               checksum += main_clk;
+       }
+
+       /* The value of all bytes combines must be 0 */
+       ts->main_clk[GOODIX_MAIN_CLK_LEN - 1] = 256 - checksum;
+
+       return goodix_i2c_write(ts->client, GOODIX_REG_MAIN_CLK,
+                               ts->main_clk, GOODIX_MAIN_CLK_LEN);
+}
+
+int goodix_firmware_check(struct goodix_ts_data *ts)
+{
+       device_property_read_string(&ts->client->dev,
+                                   "firmware-name", &ts->firmware_name);
+       if (!ts->firmware_name)
+               return 0;
+
+       if (ts->irq_pin_access_method == IRQ_PIN_ACCESS_NONE) {
+               dev_err(&ts->client->dev, "Error no IRQ-pin access method, cannot upload fw.\n");
+               return -EINVAL;
+       }
+
+       dev_info(&ts->client->dev, "Touchscreen controller needs fw-upload\n");
+       ts->load_cfg_from_disk = true;
+
+       return goodix_firmware_upload(ts);
+}
+
+bool goodix_handle_fw_request(struct goodix_ts_data *ts)
+{
+       int error;
+       u8 val;
+
+       error = goodix_i2c_read(ts->client, GOODIX_REG_REQUEST, &val, 1);
+       if (error)
+               return false;
+
+       switch (val) {
+       case GOODIX_RQST_RESPONDED:
+               /*
+                * If we read back our own last ack the IRQ was not for
+                * a request.
+                */
+               return false;
+       case GOODIX_RQST_CONFIG:
+               error = goodix_send_cfg(ts, ts->config, ts->chip->config_len);
+               if (error)
+                       return false;
+
+               break;
+       case GOODIX_RQST_BAK_REF:
+               error = goodix_prepare_bak_ref(ts);
+               if (error)
+                       return false;
+
+               error = goodix_i2c_write(ts->client, GOODIX_REG_BAK_REF,
+                                        ts->bak_ref, ts->bak_ref_len);
+               if (error)
+                       return false;
+
+               break;
+       case GOODIX_RQST_RESET:
+               error = goodix_firmware_upload(ts);
+               if (error)
+                       return false;
+
+               break;
+       case GOODIX_RQST_MAIN_CLOCK:
+               error = goodix_send_main_clock(ts);
+               if (error)
+                       return false;
+
+               break;
+       case GOODIX_RQST_UNKNOWN:
+       case GOODIX_RQST_IDLE:
+               break;
+       default:
+               dev_err_ratelimited(&ts->client->dev, "Unknown Request: 0x%02x\n", val);
+       }
+
+       /* Ack the request */
+       goodix_i2c_write_u8(ts->client,
+                           GOODIX_REG_REQUEST, GOODIX_RQST_RESPONDED);
+       return true;
+}
+
+void goodix_save_bak_ref(struct goodix_ts_data *ts)
+{
+       int error;
+       u8 val;
+
+       if (!ts->firmware_name)
+               return;
+
+       error = goodix_i2c_read(ts->client, GOODIX_REG_STATUS, &val, 1);
+       if (error)
+               return;
+
+       if (!(val & 0x80))
+               return;
+
+       error = goodix_i2c_read(ts->client, GOODIX_REG_BAK_REF,
+                               ts->bak_ref, ts->bak_ref_len);
+       if (error) {
+               memset(ts->bak_ref, 0, ts->bak_ref_len);
+               ts->bak_ref[ts->bak_ref_len - 1] = 1;
+       }
+}