[media] introduce gspca-stk1135: Syntek STK1135 driver

Hello,
this is a new gspca driver for Syntek STK1135 webcams. The code is completely
new, but register values are based on Syntekdriver (stk11xx) by Nicolas VIVIEN
(http://syntekdriver.sourceforge.net).
Only one webcam type is supported now - vendor 0x174f, device 0x6a31.
It's Asus F5RL laptop flippable webcam with MT9M112.
The camera works better than in Windows - initializes much faster and
provides more resolutions (the sensor can do almost any resolution - just
add it to the stk1135_modes[] - could this feature be somehow used by
applications to avoid SW scaling?).
Autoflip works too - when the camera is flipped around, the image is flipped
automatically.

Signed-off-by: Ondrej Zary <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/usb/gspca/Kconfig

···
 	  To compile this driver as a module, choose M here: the
 	  module will be called gspca_stk014.
 
+config USB_GSPCA_STK1135
+	tristate "Syntek STK1135 USB Camera Driver"
+	depends on VIDEO_V4L2 && USB_GSPCA
+	help
+	  Say Y here if you want support for cameras based on the STK1135 chip.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gspca_stk1135.
+
 config USB_GSPCA_STV0680
 	tristate "STV0680 USB Camera Driver"
 	depends on VIDEO_V4L2 && USB_GSPCA

drivers/media/usb/gspca/Makefile

···
 obj-$(CONFIG_USB_GSPCA_SQ930X)   += gspca_sq930x.o
 obj-$(CONFIG_USB_GSPCA_SUNPLUS)  += gspca_sunplus.o
 obj-$(CONFIG_USB_GSPCA_STK014)   += gspca_stk014.o
+obj-$(CONFIG_USB_GSPCA_STK1135)  += gspca_stk1135.o
 obj-$(CONFIG_USB_GSPCA_STV0680)  += gspca_stv0680.o
 obj-$(CONFIG_USB_GSPCA_T613)     += gspca_t613.o
 obj-$(CONFIG_USB_GSPCA_TOPRO)    += gspca_topro.o
···
 gspca_sq905c-objs   := sq905c.o
 gspca_sq930x-objs   := sq930x.o
 gspca_stk014-objs   := stk014.o
+gspca_stk1135-objs  := stk1135.o
 gspca_stv0680-objs  := stv0680.o
 gspca_sunplus-objs  := sunplus.o
 gspca_t613-objs     := t613.o

drivers/media/usb/gspca/stk1135.c

···
+/*
+ * Syntek STK1135 subdriver
+ *
+ * Copyright (c) 2013 Ondrej Zary
+ *
+ * Based on Syntekdriver (stk11xx) by Nicolas VIVIEN:
+ *   http://syntekdriver.sourceforge.net
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define MODULE_NAME "stk1135"
+
+#include "gspca.h"
+#include "stk1135.h"
+
+MODULE_AUTHOR("Ondrej Zary");
+MODULE_DESCRIPTION("Syntek STK1135 USB Camera Driver");
+MODULE_LICENSE("GPL");
+
+
+/* specific webcam descriptor */
+struct sd {
+	struct gspca_dev gspca_dev;	/* !! must be the first item */
+
+	u8 pkt_seq;
+	u8 sensor_page;
+
+	bool flip_status;
+	u8 flip_debounce;
+
+	struct v4l2_ctrl *hflip;
+	struct v4l2_ctrl *vflip;
+};
+
+static const struct v4l2_pix_format stk1135_modes[] = {
+	{160, 120, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 160,
+		.sizeimage = 160 * 120,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{176, 144, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 176,
+		.sizeimage = 176 * 144,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{320, 240, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 320,
+		.sizeimage = 320 * 240,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{352, 288, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 352,
+		.sizeimage = 352 * 288,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{640, 480, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 640,
+		.sizeimage = 640 * 480,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{720, 576, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 720,
+		.sizeimage = 720 * 576,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{800, 600, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 800,
+		.sizeimage = 800 * 600,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{1024, 768, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 1024,
+		.sizeimage = 1024 * 768,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+	{1280, 1024, V4L2_PIX_FMT_SBGGR8, V4L2_FIELD_NONE,
+		.bytesperline = 1280,
+		.sizeimage = 1280 * 1024,
+		.colorspace = V4L2_COLORSPACE_SRGB},
+};
+
+/* -- read a register -- */
+static u8 reg_r(struct gspca_dev *gspca_dev, u16 index)
+{
+	struct usb_device *dev = gspca_dev->dev;
+	int ret;
+
+	if (gspca_dev->usb_err < 0)
+		return 0;
+	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+			0x00,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			0x00,
+			index,
+			gspca_dev->usb_buf, 1,
+			500);
+
+	PDEBUG(D_USBI, "reg_r 0x%x=0x%02x", index, gspca_dev->usb_buf[0]);
+	if (ret < 0) {
+		pr_err("reg_r 0x%x err %d\n", index, ret);
+		gspca_dev->usb_err = ret;
+		return 0;
+	}
+
+	return gspca_dev->usb_buf[0];
+}
+
+/* -- write a register -- */
+static void reg_w(struct gspca_dev *gspca_dev, u16 index, u8 val)
+{
+	int ret;
+	struct usb_device *dev = gspca_dev->dev;
+
+	if (gspca_dev->usb_err < 0)
+		return;
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+			0x01,
+			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			val,
+			index,
+			NULL,
+			0,
+			500);
+	PDEBUG(D_USBO, "reg_w 0x%x:=0x%02x", index, val);
+	if (ret < 0) {
+		pr_err("reg_w 0x%x err %d\n", index, ret);
+		gspca_dev->usb_err = ret;
+	}
+}
+
+static void reg_w_mask(struct gspca_dev *gspca_dev, u16 index, u8 val, u8 mask)
+{
+	val = (reg_r(gspca_dev, index) & ~mask) | (val & mask);
+	reg_w(gspca_dev, index, val);
+}
+
+/* this function is called at probe time */
+static int sd_config(struct gspca_dev *gspca_dev,
+			const struct usb_device_id *id)
+{
+	gspca_dev->cam.cam_mode = stk1135_modes;
+	gspca_dev->cam.nmodes = ARRAY_SIZE(stk1135_modes);
+	return 0;
+}
+
+static int stk1135_serial_wait_ready(struct gspca_dev *gspca_dev)
+{
+	int i = 0;
+	u8 val;
+
+	do {
+		val = reg_r(gspca_dev, STK1135_REG_SICTL + 1);
+		if (i++ > 500) { /* maximum retry count */
+			pr_err("serial bus timeout: status=0x%02x\n", val);
+			return -1;
+		}
+	/* repeat if BUSY or WRITE/READ not finished */
+	} while ((val & 0x10) || !(val & 0x05));
+
+	return 0;
+}
+
+static u8 sensor_read_8(struct gspca_dev *gspca_dev, u8 addr)
+{
+	reg_w(gspca_dev, STK1135_REG_SBUSR, addr);
+	/* begin read */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x20);
+	/* wait until finished */
+	if (stk1135_serial_wait_ready(gspca_dev)) {
+		pr_err("Sensor read failed\n");
+		return 0;
+	}
+
+	return reg_r(gspca_dev, STK1135_REG_SBUSR + 1);
+}
+
+static u16 sensor_read_16(struct gspca_dev *gspca_dev, u8 addr)
+{
+	return (sensor_read_8(gspca_dev, addr) << 8) |
+		sensor_read_8(gspca_dev, 0xf1);
+}
+
+static void sensor_write_8(struct gspca_dev *gspca_dev, u8 addr, u8 data)
+{
+	/* load address and data registers */
+	reg_w(gspca_dev, STK1135_REG_SBUSW, addr);
+	reg_w(gspca_dev, STK1135_REG_SBUSW + 1, data);
+	/* begin write */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x01);
+	/* wait until finished */
+	if (stk1135_serial_wait_ready(gspca_dev)) {
+		pr_err("Sensor write failed\n");
+		return;
+	}
+}
+
+static void sensor_write_16(struct gspca_dev *gspca_dev, u8 addr, u16 data)
+{
+	sensor_write_8(gspca_dev, addr, data >> 8);
+	sensor_write_8(gspca_dev, 0xf1, data & 0xff);
+}
+
+static void sensor_set_page(struct gspca_dev *gspca_dev, u8 page)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (page != sd->sensor_page) {
+		sensor_write_16(gspca_dev, 0xf0, page);
+		sd->sensor_page = page;
+	}
+}
+
+static u16 sensor_read(struct gspca_dev *gspca_dev, u16 reg)
+{
+	sensor_set_page(gspca_dev, reg >> 8);
+	return sensor_read_16(gspca_dev, reg & 0xff);
+}
+
+static void sensor_write(struct gspca_dev *gspca_dev, u16 reg, u16 val)
+{
+	sensor_set_page(gspca_dev, reg >> 8);
+	sensor_write_16(gspca_dev, reg & 0xff, val);
+}
+
+static void sensor_write_mask(struct gspca_dev *gspca_dev,
+			u16 reg, u16 val, u16 mask)
+{
+	val = (sensor_read(gspca_dev, reg) & ~mask) | (val & mask);
+	sensor_write(gspca_dev, reg, val);
+}
+
+struct sensor_val {
+	u16 reg;
+	u16 val;
+};
+
+/* configure MT9M112 sensor */
+static void stk1135_configure_mt9m112(struct gspca_dev *gspca_dev)
+{
+	static const struct sensor_val cfg[] = {
+		/* restart&reset, chip enable, reserved */
+		{ 0x00d, 0x000b }, { 0x00d, 0x0008 }, { 0x035, 0x0022 },
+		/* mode ctl: AWB on, AE both, clip aper corr, defect corr, AE */
+		{ 0x106, 0x700e },
+
+		{ 0x2dd, 0x18e0 }, /* B-R thresholds, */
+
+		/* AWB */
+		{ 0x21f, 0x0180 }, /* Cb and Cr limits */
+		{ 0x220, 0xc814 }, { 0x221, 0x8080 }, /* lum limits, RGB gain */
+		{ 0x222, 0xa078 }, { 0x223, 0xa078 }, /* R, B limit */
+		{ 0x224, 0x5f20 }, { 0x228, 0xea02 }, /* mtx adj lim, adv ctl */
+		{ 0x229, 0x867a }, /* wide gates */
+
+		/* Color correction */
+		/* imager gains base, delta, delta signs */
+		{ 0x25e, 0x594c }, { 0x25f, 0x4d51 }, { 0x260, 0x0002 },
+		/* AWB adv ctl 2, gain offs */
+		{ 0x2ef, 0x0008 }, { 0x2f2, 0x0000 },
+		/* base matrix signs, scale K1-5, K6-9 */
+		{ 0x202, 0x00ee }, { 0x203, 0x3923 }, { 0x204, 0x0724 },
+		/* base matrix coef */
+		{ 0x209, 0x00cd }, { 0x20a, 0x0093 }, { 0x20b, 0x0004 },/*K1-3*/
+		{ 0x20c, 0x005c }, { 0x20d, 0x00d9 }, { 0x20e, 0x0053 },/*K4-6*/
+		{ 0x20f, 0x0008 }, { 0x210, 0x0091 }, { 0x211, 0x00cf },/*K7-9*/
+		{ 0x215, 0x0000 }, /* delta mtx signs */
+		/* delta matrix coef */
+		{ 0x216, 0x0000 }, { 0x217, 0x0000 }, { 0x218, 0x0000 },/*D1-3*/
+		{ 0x219, 0x0000 }, { 0x21a, 0x0000 }, { 0x21b, 0x0000 },/*D4-6*/
+		{ 0x21c, 0x0000 }, { 0x21d, 0x0000 }, { 0x21e, 0x0000 },/*D7-9*/
+		/* enable & disable manual WB to apply color corr. settings */
+		{ 0x106, 0xf00e }, { 0x106, 0x700e },
+
+		/* Lens shading correction */
+		{ 0x180, 0x0007 }, /* control */
+		/* vertical knee 0, 2+1, 4+3 */
+		{ 0x181, 0xde13 }, { 0x182, 0xebe2 }, { 0x183, 0x00f6 }, /* R */
+		{ 0x184, 0xe114 }, { 0x185, 0xeadd }, { 0x186, 0xfdf6 }, /* G */
+		{ 0x187, 0xe511 }, { 0x188, 0xede6 }, { 0x189, 0xfbf7 }, /* B */
+		/* horizontal knee 0, 2+1, 4+3, 5 */
+		{ 0x18a, 0xd613 }, { 0x18b, 0xedec }, /* R .. */
+		{ 0x18c, 0xf9f2 }, { 0x18d, 0x0000 }, /* .. R */
+		{ 0x18e, 0xd815 }, { 0x18f, 0xe9ea }, /* G .. */
+		{ 0x190, 0xf9f1 }, { 0x191, 0x0002 }, /* .. G */
+		{ 0x192, 0xde10 }, { 0x193, 0xefef }, /* B .. */
+		{ 0x194, 0xfbf4 }, { 0x195, 0x0002 }, /* .. B */
+		/* vertical knee 6+5, 8+7 */
+		{ 0x1b6, 0x0e06 }, { 0x1b7, 0x2713 }, /* R */
+		{ 0x1b8, 0x1106 }, { 0x1b9, 0x2713 }, /* G */
+		{ 0x1ba, 0x0c03 }, { 0x1bb, 0x2a0f }, /* B */
+		/* horizontal knee 7+6, 9+8, 10 */
+		{ 0x1bc, 0x1208 }, { 0x1bd, 0x1a16 }, { 0x1be, 0x0022 }, /* R */
+		{ 0x1bf, 0x150a }, { 0x1c0, 0x1c1a }, { 0x1c1, 0x002d }, /* G */
+		{ 0x1c2, 0x1109 }, { 0x1c3, 0x1414 }, { 0x1c4, 0x002a }, /* B */
+		{ 0x106, 0x740e }, /* enable lens shading correction */
+
+		/* Gamma correction - context A */
+		{ 0x153, 0x0b03 }, { 0x154, 0x4722 }, { 0x155, 0xac82 },
+		{ 0x156, 0xdac7 }, { 0x157, 0xf5e9 }, { 0x158, 0xff00 },
+		/* Gamma correction - context B */
+		{ 0x1dc, 0x0b03 }, { 0x1dd, 0x4722 }, { 0x1de, 0xac82 },
+		{ 0x1df, 0xdac7 }, { 0x1e0, 0xf5e9 }, { 0x1e1, 0xff00 },
+
+		/* output format: RGB, invert output pixclock, output bayer */
+		{ 0x13a, 0x4300 }, { 0x19b, 0x4300 }, /* for context A, B */
+		{ 0x108, 0x0180 }, /* format control - enable bayer row flip */
+
+		{ 0x22f, 0xd100 }, { 0x29c, 0xd100 }, /* AE A, B */
+
+		/* default prg conf, prg ctl - by 0x2d2, prg advance - PA1 */
+		{ 0x2d2, 0x0000 }, { 0x2cc, 0x0004 }, { 0x2cb, 0x0001 },
+
+		{ 0x22e, 0x0c3c }, { 0x267, 0x1010 }, /* AE tgt ctl, gain lim */
+
+		/* PLL */
+		{ 0x065, 0xa000 }, /* clk ctl - enable PLL (clear bit 14) */
+		{ 0x066, 0x2003 }, { 0x067, 0x0501 }, /* PLL M=128, N=3, P=1 */
+		{ 0x065, 0x2000 }, /* disable PLL bypass (clear bit 15) */
+
+		{ 0x005, 0x01b8 }, { 0x007, 0x00d8 }, /* horiz blanking B, A */
+
+		/* AE line size, shutter delay limit */
+		{ 0x239, 0x06c0 }, { 0x23b, 0x040e }, /* for context A */
+		{ 0x23a, 0x06c0 }, { 0x23c, 0x0564 }, /* for context B */
+		/* shutter width basis 60Hz, 50Hz */
+		{ 0x257, 0x0208 }, { 0x258, 0x0271 }, /* for context A */
+		{ 0x259, 0x0209 }, { 0x25a, 0x0271 }, /* for context B */
+
+		{ 0x25c, 0x120d }, { 0x25d, 0x1712 }, /* flicker 60Hz, 50Hz */
+		{ 0x264, 0x5e1c }, /* reserved */
+		/* flicker, AE gain limits, gain zone limits */
+		{ 0x25b, 0x0003 }, { 0x236, 0x7810 }, { 0x237, 0x8304 },
+
+		{ 0x008, 0x0021 }, /* vert blanking A */
+	};
+	int i;
+	u16 width, height;
+
+	for (i = 0; i < ARRAY_SIZE(cfg); i++)
+		sensor_write(gspca_dev, cfg[i].reg, cfg[i].val);
+
+	/* set output size */
+	width = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].width;
+	height = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].height;
+	if (width <= 640) { /* use context A (half readout speed by default) */
+		sensor_write(gspca_dev, 0x1a7, width);
+		sensor_write(gspca_dev, 0x1aa, height);
+		/* set read mode context A */
+		sensor_write(gspca_dev, 0x0c8, 0x0000);
+		/* set resize, read mode, vblank, hblank context A */
+		sensor_write(gspca_dev, 0x2c8, 0x0000);
+	} else { /* use context B (full readout speed by default) */
+		sensor_write(gspca_dev, 0x1a1, width);
+		sensor_write(gspca_dev, 0x1a4, height);
+		/* set read mode context B */
+		sensor_write(gspca_dev, 0x0c8, 0x0008);
+		/* set resize, read mode, vblank, hblank context B */
+		sensor_write(gspca_dev, 0x2c8, 0x040b);
+	}
+}
+
+static void stk1135_configure_clock(struct gspca_dev *gspca_dev)
+{
+	/* configure SCLKOUT */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x12);
+	/* set 1 clock per pixel */
+	/* and positive edge clocked pulse high when pixel counter = 0 */
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 0, 0x41);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_TCP1 + 3, 0x00);
+
+	/* enable CLKOUT for sensor */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 0, 0x10);
+	/* disable STOP clock */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 1, 0x00);
+	/* set lower 8 bits of PLL feedback divider */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 3, 0x07);
+	/* set other PLL parameters */
+	reg_w(gspca_dev, STK1135_REG_PLLFD, 0x06);
+	/* enable timing generator */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x80);
+	/* enable PLL */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 2, 0x04);
+
+	/* set serial interface clock divider (30MHz/0x1f*16+2) = 60240 kHz) */
+	reg_w(gspca_dev, STK1135_REG_SICTL + 2, 0x1f);
+}
+
+static void stk1135_camera_disable(struct gspca_dev *gspca_dev)
+{
+	/* set capture end Y position to 0 */
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 3, 0x00);
+	/* disable capture */
+	reg_w_mask(gspca_dev, STK1135_REG_SCTRL, 0x00, 0x80);
+
+	/* enable sensor standby and diasble chip enable */
+	sensor_write_mask(gspca_dev, 0x00d, 0x0004, 0x000c);
+
+	/* disable PLL */
+	reg_w_mask(gspca_dev, STK1135_REG_SENSO + 2, 0x00, 0x01);
+	/* disable timing generator */
+	reg_w(gspca_dev, STK1135_REG_TMGEN, 0x00);
+	/* enable STOP clock */
+	reg_w(gspca_dev, STK1135_REG_SENSO + 1, 0x20);
+	/* disable CLKOUT for sensor */
+	reg_w(gspca_dev, STK1135_REG_SENSO, 0x00);
+
+	/* disable sensor (GPIO5) and enable GPIO0,3,6 (?) - sensor standby? */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, 0x49);
+}
+
+/* this function is called at probe and resume time */
+static int sd_init(struct gspca_dev *gspca_dev)
+{
+	u16 sensor_id;
+	char *sensor_name;
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	/* set GPIO3,4,5,6 direction to output */
+	reg_w(gspca_dev, STK1135_REG_GCTRL + 2, 0x78);
+	/* enable sensor (GPIO5) */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, (1 << 5));
+	/* disable ROM interface */
+	reg_w(gspca_dev, STK1135_REG_GCTRL + 3, 0x80);
+	/* enable interrupts from GPIO8 (flip sensor) and GPIO9 (???) */
+	reg_w(gspca_dev, STK1135_REG_ICTRL + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_ICTRL + 3, 0x03);
+	/* enable remote wakeup from GPIO9 (???) */
+	reg_w(gspca_dev, STK1135_REG_RMCTL + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_RMCTL + 3, 0x02);
+
+	/* reset serial interface */
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x80);
+	reg_w(gspca_dev, STK1135_REG_SICTL, 0x00);
+	/* set sensor address */
+	reg_w(gspca_dev, STK1135_REG_SICTL + 3, 0xba);
+	/* disable alt 2-wire serial interface */
+	reg_w(gspca_dev, STK1135_REG_ASIC + 3, 0x00);
+
+	stk1135_configure_clock(gspca_dev);
+
+	/* read sensor ID */
+	sd->sensor_page = 0xff;
+	sensor_id = sensor_read(gspca_dev, 0x000);
+
+	switch (sensor_id) {
+	case 0x148c:
+		sensor_name = "MT9M112";
+		break;
+	default:
+		sensor_name = "unknown";
+	}
+	pr_info("Detected sensor type %s (0x%x)\n", sensor_name, sensor_id);
+
+	stk1135_camera_disable(gspca_dev);
+
+	return gspca_dev->usb_err;
+}
+
+/* -- start the camera -- */
+static int sd_start(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	u16 width, height;
+
+	/* enable sensor (GPIO5) */
+	reg_w(gspca_dev, STK1135_REG_GCTRL, (1 << 5));
+
+	stk1135_configure_clock(gspca_dev);
+
+	/* set capture start position X = 0, Y = 0 */
+	reg_w(gspca_dev, STK1135_REG_CISPO + 0, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 1, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 2, 0x00);
+	reg_w(gspca_dev, STK1135_REG_CISPO + 3, 0x00);
+
+	/* set capture end position */
+	width = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].width;
+	height = gspca_dev->cam.cam_mode[gspca_dev->curr_mode].height;
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 0, width & 0xff);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 1, width >> 8);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 2, height & 0xff);
+	reg_w(gspca_dev, STK1135_REG_CIEPO + 3, height >> 8);
+
+	/* set 8-bit mode */
+	reg_w(gspca_dev, STK1135_REG_SCTRL, 0x20);
+
+	stk1135_configure_mt9m112(gspca_dev);
+
+	/* enable capture */
+	reg_w_mask(gspca_dev, STK1135_REG_SCTRL, 0x80, 0x80);
+
+	if (gspca_dev->usb_err >= 0)
+		PDEBUG(D_STREAM, "camera started alt: 0x%02x",
+				gspca_dev->alt);
+
+	sd->pkt_seq = 0;
+
+	return gspca_dev->usb_err;
+}
+
+static void sd_stopN(struct gspca_dev *gspca_dev)
+{
+	struct usb_device *dev = gspca_dev->dev;
+
+	usb_set_interface(dev, gspca_dev->iface, 0);
+
+	stk1135_camera_disable(gspca_dev);
+
+	PDEBUG(D_STREAM, "camera stopped");
+}
+
+static void sd_pkt_scan(struct gspca_dev *gspca_dev,
+			u8 *data,			/* isoc packet */
+			int len)			/* iso packet length */
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	int skip = sizeof(struct stk1135_pkt_header);
+	bool flip;
+	enum gspca_packet_type pkt_type = INTER_PACKET;
+	struct stk1135_pkt_header *hdr = (void *)data;
+	u8 seq;
+
+	if (len < 4) {
+		PDEBUG(D_PACK, "received short packet (less than 4 bytes)");
+		return;
+	}
+
+	/* GPIO 8 is flip sensor (1 = normal position, 0 = flipped to back) */
+	flip = !(le16_to_cpu(hdr->gpio) & (1 << 8));
+	/* it's a switch, needs software debounce */
+	if (sd->flip_status != flip)
+		sd->flip_debounce++;
+	else
+		sd->flip_debounce = 0;
+
+	/* check sequence number (not present in new frame packets) */
+	if (!(hdr->flags & STK1135_HDR_FRAME_START)) {
+		seq = hdr->seq & STK1135_HDR_SEQ_MASK;
+		if (seq != sd->pkt_seq) {
+			PDEBUG(D_PACK, "received out-of-sequence packet");
+			/* resync sequence and discard packet */
+			sd->pkt_seq = seq;
+			gspca_dev->last_packet_type = DISCARD_PACKET;
+			return;
+		}
+	}
+	sd->pkt_seq++;
+	if (sd->pkt_seq > STK1135_HDR_SEQ_MASK)
+		sd->pkt_seq = 0;
+
+	if (len == sizeof(struct stk1135_pkt_header))
+		return;
+
+	if (hdr->flags & STK1135_HDR_FRAME_START) { /* new frame */
+		skip = 8;	/* the header is longer */
+		gspca_frame_add(gspca_dev, LAST_PACKET, data, 0);
+		pkt_type = FIRST_PACKET;
+	}
+	gspca_frame_add(gspca_dev, pkt_type, data + skip, len - skip);
+}
+
+static void sethflip(struct gspca_dev *gspca_dev, s32 val)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (sd->flip_status)
+		val = !val;
+	sensor_write_mask(gspca_dev, 0x020, val ? 0x0002 : 0x0000 , 0x0002);
+}
+
+static void setvflip(struct gspca_dev *gspca_dev, s32 val)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (sd->flip_status)
+		val = !val;
+	sensor_write_mask(gspca_dev, 0x020, val ? 0x0001 : 0x0000 , 0x0001);
+}
+
+static void stk1135_dq_callback(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (sd->flip_debounce > 100) {
+		sd->flip_status = !sd->flip_status;
+		sethflip(gspca_dev, v4l2_ctrl_g_ctrl(sd->hflip));
+		setvflip(gspca_dev, v4l2_ctrl_g_ctrl(sd->vflip));
+	}
+}
+
+static int sd_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct gspca_dev *gspca_dev =
+		container_of(ctrl->handler, struct gspca_dev, ctrl_handler);
+
+	gspca_dev->usb_err = 0;
+
+	if (!gspca_dev->streaming)
+		return 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_HFLIP:
+		sethflip(gspca_dev, ctrl->val);
+		break;
+	case V4L2_CID_VFLIP:
+		setvflip(gspca_dev, ctrl->val);
+		break;
+	}
+
+	return gspca_dev->usb_err;
+}
+
+static const struct v4l2_ctrl_ops sd_ctrl_ops = {
+	.s_ctrl = sd_s_ctrl,
+};
+
+static int sd_init_controls(struct gspca_dev *gspca_dev)
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+	struct v4l2_ctrl_handler *hdl = &gspca_dev->ctrl_handler;
+
+	gspca_dev->vdev.ctrl_handler = hdl;
+	v4l2_ctrl_handler_init(hdl, 2);
+	sd->hflip = v4l2_ctrl_new_std(hdl, &sd_ctrl_ops,
+			V4L2_CID_HFLIP, 0, 1, 1, 0);
+	sd->vflip = v4l2_ctrl_new_std(hdl, &sd_ctrl_ops,
+			V4L2_CID_VFLIP, 0, 1, 1, 0);
+
+	if (hdl->error) {
+		pr_err("Could not initialize controls\n");
+		return hdl->error;
+	}
+	return 0;
+}
+
+/* sub-driver description */
+static const struct sd_desc sd_desc = {
+	.name = MODULE_NAME,
+	.config = sd_config,
+	.init = sd_init,
+	.init_controls = sd_init_controls,
+	.start = sd_start,
+	.stopN = sd_stopN,
+	.pkt_scan = sd_pkt_scan,
+	.dq_callback = stk1135_dq_callback,
+};
+
+/* -- module initialisation -- */
+static const struct usb_device_id device_table[] = {
+	{USB_DEVICE(0x174f, 0x6a31)},	/* ASUS laptop, MT9M112 sensor */
+	{}
+};
+MODULE_DEVICE_TABLE(usb, device_table);
+
+/* -- device connect -- */
+static int sd_probe(struct usb_interface *intf,
+			const struct usb_device_id *id)
+{
+	return gspca_dev_probe(intf, id, &sd_desc, sizeof(struct sd),
+				THIS_MODULE);
+}
+
+static struct usb_driver sd_driver = {
+	.name = MODULE_NAME,
+	.id_table = device_table,
+	.probe = sd_probe,
+	.disconnect = gspca_disconnect,
+#ifdef CONFIG_PM
+	.suspend = gspca_suspend,
+	.resume = gspca_resume,
+	.reset_resume = gspca_resume,
+#endif
+};
+
+module_usb_driver(sd_driver);

drivers/media/usb/gspca/stk1135.h

···
+/*
+ * STK1135 registers
+ *
+ * Copyright (c) 2013 Ondrej Zary
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#define STK1135_REG_GCTRL	0x000	/* GPIO control */
+#define STK1135_REG_ICTRL	0x004	/* Interrupt control */
+#define STK1135_REG_IDATA	0x008	/* Interrupt data */
+#define STK1135_REG_RMCTL	0x00c	/* Remote wakeup control */
+#define STK1135_REG_POSVA	0x010	/* Power-on strapping data */
+
+#define STK1135_REG_SENSO	0x018	/* Sensor select options */
+#define STK1135_REG_PLLFD	0x01c	/* PLL frequency divider */
+
+#define STK1135_REG_SCTRL	0x100	/* Sensor control register */
+#define STK1135_REG_DCTRL	0x104	/* Decimation control register */
+#define STK1135_REG_CISPO	0x110	/* Capture image starting position */
+#define STK1135_REG_CIEPO	0x114	/* Capture image ending position */
+#define STK1135_REG_TCTRL	0x120	/* Test data control */
+
+#define STK1135_REG_SICTL	0x200	/* Serial interface control register */
+#define STK1135_REG_SBUSW	0x204	/* Serial bus write */
+#define STK1135_REG_SBUSR	0x208	/* Serial bus read */
+#define STK1135_REG_SCSI	0x20c	/* Software control serial interface */
+#define STK1135_REG_GSBWP	0x210	/* General serial bus write port */
+#define STK1135_REG_GSBRP	0x214	/* General serial bus read port */
+#define STK1135_REG_ASIC	0x2fc	/* Alternate serial interface control */
+
+#define STK1135_REG_TMGEN	0x300	/* Timing generator */
+#define STK1135_REG_TCP1	0x350	/* Timing control parameter 1 */
+
+struct stk1135_pkt_header {
+	u8 flags;
+	u8 seq;
+	__le16 gpio;
+} __packed;
+
+#define STK1135_HDR_FRAME_START	(1 << 7)
+#define STK1135_HDR_ODD		(1 << 6)
+#define STK1135_HDR_I2C_VBLANK	(1 << 5)
+
+#define STK1135_HDR_SEQ_MASK	0x3f