Input: goodix - add support for controllers without flash

Some Goodix touchscreen controllers, such as for example the GT912,
don't have flash-storage for their firmware.

These models require the OS to load the firmware at runtime, as well as
some other special handling. Add support for this to the goodix driver.

This patch was developed and tested on a Glavey TM800A550L tablet.

Note the "goodix,main-clk" and "firmware-name" device-properties used
by the new code are *not* documented in the
Documentation/devicetree/bindings/input/touchscreen/goodix.yaml
device-tree bindings for now.

Not documenting these is intentional. This is done because this code has
only been tested on x86/ACPI so far, where devicetree is not used.
Instead these properties are set through a software-fwnode attached to the
device by the drivers/platform/x86/touchscreen_dmi.c code. This means that
the use of this properties for now is purely a kernel-internal thing and
the name/working of the properties may still be changed for now.

Reviewed-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210920150643.155872-7-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 427 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/goodix_fwupload.c b/drivers/input/touchscreen/goodix_fwupload.c
new file mode 100644
index 000000000000..c1e7a2413078
--- /dev/null
+++ b/drivers/input/touchscreen/goodix_fwupload.c
@@ -0,0 +1,427 @@
+// 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;
+	}
+}