From: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Date: Thu, 13 Jul 2017 02:20:42 +0000 (+0900)
Subject: drm/panel: Add support for S6E63J0X03 panel
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=2a05177dac9de66eda3927c370a91fd92ad9e707;p=openwrt%2Fstaging%2Fblogic.git

drm/panel: Add support for S6E63J0X03 panel

This patch adds MIPI-DSI based S6E63J0X03 AMOLED LCD panel driver
which uses MIPI DSI bus to communicate with panel. The panel has
320×320 resolution in 1.63" physical panel. This panel is used in
Samsung Galaxy Gear 2.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Hyungwon Hwang <human.hwang@samsung.com>
Signed-off-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1499912443-3671-3-git-send-email-hoegeun.kwon@samsung.com
---

diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index d84a031fae24..bc69bca74bb2 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -80,6 +80,13 @@ config DRM_PANEL_SAMSUNG_S6E3HA2
 	depends on BACKLIGHT_CLASS_DEVICE
 	select VIDEOMODE_HELPERS
 
+config DRM_PANEL_SAMSUNG_S6E63J0X03
+	tristate "Samsung S6E63J0X03 DSI command mode panel"
+	depends on OF
+	depends on DRM_MIPI_DSI
+	depends on BACKLIGHT_CLASS_DEVICE
+	select VIDEOMODE_HELPERS
+
 config DRM_PANEL_SAMSUNG_S6E8AA0
 	tristate "Samsung S6E8AA0 DSI video mode panel"
 	depends on OF
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 9f6610d08b00..42d2e295a95b 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_DRM_PANEL_LG_LG4573) += panel-lg-lg4573.o
 obj-$(CONFIG_DRM_PANEL_PANASONIC_VVX10F034N00) += panel-panasonic-vvx10f034n00.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_LD9040) += panel-samsung-ld9040.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E3HA2) += panel-samsung-s6e3ha2.o
+obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E63J0X03) += panel-samsung-s6e63j0x03.o
 obj-$(CONFIG_DRM_PANEL_SAMSUNG_S6E8AA0) += panel-samsung-s6e8aa0.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LQ101R1SX01) += panel-sharp-lq101r1sx01.o
 obj-$(CONFIG_DRM_PANEL_SHARP_LS043T1LE01) += panel-sharp-ls043t1le01.o
diff --git a/drivers/gpu/drm/panel/panel-samsung-s6e63j0x03.c b/drivers/gpu/drm/panel/panel-samsung-s6e63j0x03.c
new file mode 100644
index 000000000000..aeb32aa58899
--- /dev/null
+++ b/drivers/gpu/drm/panel/panel-samsung-s6e63j0x03.c
@@ -0,0 +1,532 @@
+/*
+ * MIPI-DSI based S6E63J0X03 AMOLED lcd 1.63 inch panel driver.
+ *
+ * Copyright (c) 2014-2017 Samsung Electronics Co., Ltd
+ *
+ * Inki Dae <inki.dae@samsung.com>
+ * Hoegeun Kwon <hoegeun.kwon@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
+#include <linux/backlight.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <video/mipi_display.h>
+
+#define MCS_LEVEL2_KEY		0xf0
+#define MCS_MTP_KEY		0xf1
+#define MCS_MTP_SET3		0xd4
+
+#define MAX_BRIGHTNESS		100
+#define DEFAULT_BRIGHTNESS	80
+
+#define NUM_GAMMA_STEPS		9
+#define GAMMA_CMD_CNT		28
+
+#define FIRST_COLUMN 20
+
+struct s6e63j0x03 {
+	struct device *dev;
+	struct drm_panel panel;
+	struct backlight_device *bl_dev;
+
+	struct regulator_bulk_data supplies[2];
+	struct gpio_desc *reset_gpio;
+};
+
+static const struct drm_display_mode default_mode = {
+	.clock = 4649,
+	.hdisplay = 320,
+	.hsync_start = 320 + 1,
+	.hsync_end = 320 + 1 + 1,
+	.htotal = 320 + 1 + 1 + 1,
+	.vdisplay = 320,
+	.vsync_start = 320 + 150,
+	.vsync_end = 320 + 150 + 1,
+	.vtotal = 320 + 150 + 1 + 2,
+	.vrefresh = 30,
+	.flags = 0,
+};
+
+static const unsigned char gamma_tbl[NUM_GAMMA_STEPS][GAMMA_CMD_CNT] = {
+	{	/* Gamma 10 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x7f, 0x7f, 0x7f, 0x52, 0x6b, 0x6f, 0x26,
+		0x28, 0x2d, 0x28, 0x26, 0x27, 0x33, 0x34, 0x32, 0x36, 0x36,
+		0x35, 0x00, 0xab, 0x00, 0xae, 0x00, 0xbf
+	},
+	{	/* gamma 30 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x70, 0x7f, 0x7f, 0x4e, 0x64, 0x69, 0x26,
+		0x27, 0x2a, 0x28, 0x29, 0x27, 0x31, 0x32, 0x31, 0x35, 0x34,
+		0x35, 0x00, 0xc4, 0x00, 0xca, 0x00, 0xdc
+	},
+	{	/* gamma 60 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x65, 0x7b, 0x7d, 0x5f, 0x67, 0x68, 0x2a,
+		0x28, 0x29, 0x28, 0x2a, 0x27, 0x31, 0x2f, 0x30, 0x34, 0x33,
+		0x34, 0x00, 0xd9, 0x00, 0xe4, 0x00, 0xf5
+	},
+	{	/* gamma 90 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x4d, 0x6f, 0x71, 0x67, 0x6a, 0x6c, 0x29,
+		0x28, 0x28, 0x28, 0x29, 0x27, 0x30, 0x2e, 0x30, 0x32, 0x31,
+		0x31, 0x00, 0xea, 0x00, 0xf6, 0x01, 0x09
+	},
+	{	/* gamma 120 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x3d, 0x66, 0x68, 0x69, 0x69, 0x69, 0x28,
+		0x28, 0x27, 0x28, 0x28, 0x27, 0x30, 0x2e, 0x2f, 0x31, 0x31,
+		0x30, 0x00, 0xf9, 0x01, 0x05, 0x01, 0x1b
+	},
+	{	/* gamma 150 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x31, 0x51, 0x53, 0x66, 0x66, 0x67, 0x28,
+		0x29, 0x27, 0x28, 0x27, 0x27, 0x2e, 0x2d, 0x2e, 0x31, 0x31,
+		0x30, 0x01, 0x04, 0x01, 0x11, 0x01, 0x29
+	},
+	{	/* gamma 200 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x2f, 0x4f, 0x51, 0x67, 0x65, 0x65, 0x29,
+		0x2a, 0x28, 0x27, 0x25, 0x26, 0x2d, 0x2c, 0x2c, 0x30, 0x30,
+		0x30, 0x01, 0x14, 0x01, 0x23, 0x01, 0x3b
+	},
+	{	/* gamma 240 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x2c, 0x4d, 0x50, 0x65, 0x63, 0x64, 0x2a,
+		0x2c, 0x29, 0x26, 0x24, 0x25, 0x2c, 0x2b, 0x2b, 0x30, 0x30,
+		0x30, 0x01, 0x1e, 0x01, 0x2f, 0x01, 0x47
+	},
+	{	/* gamma 300 */
+		MCS_MTP_SET3,
+		0x00, 0x00, 0x00, 0x38, 0x61, 0x64, 0x65, 0x63, 0x64, 0x28,
+		0x2a, 0x27, 0x26, 0x23, 0x25, 0x2b, 0x2b, 0x2a, 0x30, 0x2f,
+		0x30, 0x01, 0x2d, 0x01, 0x3f, 0x01, 0x57
+	}
+};
+
+static inline struct s6e63j0x03 *panel_to_s6e63j0x03(struct drm_panel *panel)
+{
+	return container_of(panel, struct s6e63j0x03, panel);
+}
+
+static inline ssize_t s6e63j0x03_dcs_write_seq(struct s6e63j0x03 *ctx,
+					const void *seq, size_t len)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
+
+	return mipi_dsi_dcs_write_buffer(dsi, seq, len);
+}
+
+#define s6e63j0x03_dcs_write_seq_static(ctx, seq...)			\
+	({								\
+		static const u8 d[] = { seq };				\
+		s6e63j0x03_dcs_write_seq(ctx, d, ARRAY_SIZE(d));	\
+	})
+
+static inline int s6e63j0x03_enable_lv2_command(struct s6e63j0x03 *ctx)
+{
+	return s6e63j0x03_dcs_write_seq_static(ctx, MCS_LEVEL2_KEY, 0x5a, 0x5a);
+}
+
+static inline int s6e63j0x03_apply_mtp_key(struct s6e63j0x03 *ctx, bool on)
+{
+	if (on)
+		return s6e63j0x03_dcs_write_seq_static(ctx,
+				MCS_MTP_KEY, 0x5a, 0x5a);
+
+	return s6e63j0x03_dcs_write_seq_static(ctx, MCS_MTP_KEY, 0xa5, 0xa5);
+}
+
+static int s6e63j0x03_power_on(struct s6e63j0x03 *ctx)
+{
+	int ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+	if (ret < 0)
+		return ret;
+
+	msleep(30);
+
+	gpiod_set_value(ctx->reset_gpio, 1);
+	usleep_range(1000, 2000);
+	gpiod_set_value(ctx->reset_gpio, 0);
+	usleep_range(5000, 6000);
+
+	return 0;
+}
+
+static int s6e63j0x03_power_off(struct s6e63j0x03 *ctx)
+{
+	return regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
+}
+
+static unsigned int s6e63j0x03_get_brightness_index(unsigned int brightness)
+{
+	unsigned int index;
+
+	index = brightness / (MAX_BRIGHTNESS / NUM_GAMMA_STEPS);
+
+	if (index >= NUM_GAMMA_STEPS)
+		index = NUM_GAMMA_STEPS - 1;
+
+	return index;
+}
+
+static int s6e63j0x03_update_gamma(struct s6e63j0x03 *ctx,
+					unsigned int brightness)
+{
+	struct backlight_device *bl_dev = ctx->bl_dev;
+	unsigned int index = s6e63j0x03_get_brightness_index(brightness);
+	int ret;
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, true);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_dcs_write_seq(ctx, gamma_tbl[index], GAMMA_CMD_CNT);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, false);
+	if (ret < 0)
+		return ret;
+
+	bl_dev->props.brightness = brightness;
+
+	return 0;
+}
+
+static int s6e63j0x03_set_brightness(struct backlight_device *bl_dev)
+{
+	struct s6e63j0x03 *ctx = bl_get_data(bl_dev);
+	unsigned int brightness = bl_dev->props.brightness;
+
+	return s6e63j0x03_update_gamma(ctx, brightness);
+}
+
+static const struct backlight_ops s6e63j0x03_bl_ops = {
+	.update_status = s6e63j0x03_set_brightness,
+};
+
+static int s6e63j0x03_disable(struct drm_panel *panel)
+{
+	struct s6e63j0x03 *ctx = panel_to_s6e63j0x03(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
+	int ret;
+
+	ret = mipi_dsi_dcs_set_display_off(dsi);
+	if (ret < 0)
+		return ret;
+
+	ctx->bl_dev->props.power = FB_BLANK_NORMAL;
+
+	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
+	if (ret < 0)
+		return ret;
+
+	msleep(120);
+
+	return 0;
+}
+
+static int s6e63j0x03_unprepare(struct drm_panel *panel)
+{
+	struct s6e63j0x03 *ctx = panel_to_s6e63j0x03(panel);
+	int ret;
+
+	ret = s6e63j0x03_power_off(ctx);
+	if (ret < 0)
+		return ret;
+
+	ctx->bl_dev->props.power = FB_BLANK_POWERDOWN;
+
+	return 0;
+}
+
+static int s6e63j0x03_panel_init(struct s6e63j0x03 *ctx)
+{
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
+	int ret;
+
+	ret = s6e63j0x03_enable_lv2_command(ctx);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, true);
+	if (ret < 0)
+		return ret;
+
+	/* set porch adjustment */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xf2, 0x1c, 0x28);
+	if (ret < 0)
+		return ret;
+
+	/* set frame freq */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xb5, 0x00, 0x02, 0x00);
+	if (ret < 0)
+		return ret;
+
+	/* set caset, paset */
+	ret = mipi_dsi_dcs_set_column_address(dsi, FIRST_COLUMN,
+		default_mode.hdisplay - 1 + FIRST_COLUMN);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_set_page_address(dsi, 0, default_mode.vdisplay - 1);
+	if (ret < 0)
+		return ret;
+
+	/* set ltps timming 0, 1 */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xf8, 0x08, 0x08, 0x08, 0x17,
+		0x00, 0x2a, 0x02, 0x26, 0x00, 0x00, 0x02, 0x00, 0x00);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xf7, 0x02);
+	if (ret < 0)
+		return ret;
+
+	/* set param pos te_edge */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xb0, 0x01);
+	if (ret < 0)
+		return ret;
+
+	/* set te rising edge */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xe2, 0x0f);
+	if (ret < 0)
+		return ret;
+
+	/* set param pos default */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xb0, 0x00);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, false);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int s6e63j0x03_prepare(struct drm_panel *panel)
+{
+	struct s6e63j0x03 *ctx = panel_to_s6e63j0x03(panel);
+	int ret;
+
+	ret = s6e63j0x03_power_on(ctx);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_panel_init(ctx);
+	if (ret < 0)
+		goto err;
+
+	ctx->bl_dev->props.power = FB_BLANK_NORMAL;
+
+	return 0;
+
+err:
+	s6e63j0x03_power_off(ctx);
+	return ret;
+}
+
+static int s6e63j0x03_enable(struct drm_panel *panel)
+{
+	struct s6e63j0x03 *ctx = panel_to_s6e63j0x03(panel);
+	struct mipi_dsi_device *dsi = to_mipi_dsi_device(ctx->dev);
+	int ret;
+
+	msleep(120);
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, true);
+	if (ret < 0)
+		return ret;
+
+	/* set elvss_cond */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx, 0xb1, 0x00, 0x09);
+	if (ret < 0)
+		return ret;
+
+	/* set pos */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx,
+		MIPI_DCS_SET_ADDRESS_MODE, 0x40);
+	if (ret < 0)
+		return ret;
+
+	/* set default white brightness */
+	ret = mipi_dsi_dcs_set_display_brightness(dsi, 0x00ff);
+	if (ret < 0)
+		return ret;
+
+	/* set white ctrl */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx,
+		MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x20);
+	if (ret < 0)
+		return ret;
+
+	/* set acl off */
+	ret = s6e63j0x03_dcs_write_seq_static(ctx,
+		MIPI_DCS_WRITE_POWER_SAVE, 0x00);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_set_tear_on(dsi, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
+	if (ret < 0)
+		return ret;
+
+	ret = s6e63j0x03_apply_mtp_key(ctx, false);
+	if (ret < 0)
+		return ret;
+
+	ret = mipi_dsi_dcs_set_display_on(dsi);
+	if (ret < 0)
+		return ret;
+
+	ctx->bl_dev->props.power = FB_BLANK_UNBLANK;
+
+	return 0;
+}
+
+static int s6e63j0x03_get_modes(struct drm_panel *panel)
+{
+	struct drm_connector *connector = panel->connector;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(panel->drm, &default_mode);
+	if (!mode) {
+		DRM_ERROR("failed to add mode %ux%ux@%u\n",
+			default_mode.hdisplay, default_mode.vdisplay,
+			default_mode.vrefresh);
+		return -ENOMEM;
+	}
+
+	drm_mode_set_name(mode);
+
+	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
+	drm_mode_probed_add(connector, mode);
+
+	connector->display_info.width_mm = 29;
+	connector->display_info.height_mm = 29;
+
+	return 1;
+}
+
+static const struct drm_panel_funcs s6e63j0x03_funcs = {
+	.disable = s6e63j0x03_disable,
+	.unprepare = s6e63j0x03_unprepare,
+	.prepare = s6e63j0x03_prepare,
+	.enable = s6e63j0x03_enable,
+	.get_modes = s6e63j0x03_get_modes,
+};
+
+static int s6e63j0x03_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct s6e63j0x03 *ctx;
+	int ret;
+
+	ctx = devm_kzalloc(dev, sizeof(struct s6e63j0x03), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	mipi_dsi_set_drvdata(dsi, ctx);
+
+	ctx->dev = dev;
+
+	dsi->lanes = 1;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_EOT_PACKET;
+
+	ctx->supplies[0].supply = "vdd3";
+	ctx->supplies[1].supply = "vci";
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->supplies),
+				      ctx->supplies);
+	if (ret < 0) {
+		dev_err(dev, "failed to get regulators: %d\n", ret);
+		return ret;
+	}
+
+	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(ctx->reset_gpio)) {
+		dev_err(dev, "cannot get reset-gpio: %ld\n",
+				PTR_ERR(ctx->reset_gpio));
+		return PTR_ERR(ctx->reset_gpio);
+	}
+
+	drm_panel_init(&ctx->panel);
+	ctx->panel.dev = dev;
+	ctx->panel.funcs = &s6e63j0x03_funcs;
+
+	ctx->bl_dev = backlight_device_register("s6e63j0x03", dev, ctx,
+						&s6e63j0x03_bl_ops, NULL);
+	if (IS_ERR(ctx->bl_dev)) {
+		dev_err(dev, "failed to register backlight device\n");
+		return PTR_ERR(ctx->bl_dev);
+	}
+
+	ctx->bl_dev->props.max_brightness = MAX_BRIGHTNESS;
+	ctx->bl_dev->props.brightness = DEFAULT_BRIGHTNESS;
+	ctx->bl_dev->props.power = FB_BLANK_POWERDOWN;
+
+	ret = drm_panel_add(&ctx->panel);
+	if (ret < 0)
+		goto unregister_backlight;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0)
+		goto remove_panel;
+
+	return ret;
+
+remove_panel:
+	drm_panel_remove(&ctx->panel);
+
+unregister_backlight:
+	backlight_device_unregister(ctx->bl_dev);
+
+	return ret;
+}
+
+static int s6e63j0x03_remove(struct mipi_dsi_device *dsi)
+{
+	struct s6e63j0x03 *ctx = mipi_dsi_get_drvdata(dsi);
+
+	mipi_dsi_detach(dsi);
+	drm_panel_remove(&ctx->panel);
+
+	backlight_device_unregister(ctx->bl_dev);
+
+	return 0;
+}
+
+static const struct of_device_id s6e63j0x03_of_match[] = {
+	{ .compatible = "samsung,s6e63j0x03" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, s6e63j0x03_of_match);
+
+static struct mipi_dsi_driver s6e63j0x03_driver = {
+	.probe = s6e63j0x03_probe,
+	.remove = s6e63j0x03_remove,
+	.driver = {
+		.name = "panel_samsung_s6e63j0x03",
+		.of_match_table = s6e63j0x03_of_match,
+	},
+};
+module_mipi_dsi_driver(s6e63j0x03_driver);
+
+MODULE_AUTHOR("Inki Dae <inki.dae@samsung.com>");
+MODULE_AUTHOR("Hoegeun Kwon <hoegeun.kwon@samsung.com>");
+MODULE_DESCRIPTION("MIPI-DSI based s6e63j0x03 AMOLED LCD Panel Driver");
+MODULE_LICENSE("GPL v2");