V4L/DVB (6486): m52790: add new Mitsubishi A/V switch i2c driver

This driver is used by the ASUS Falcon2 cx23416-based cards.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/video/m52790.c b/drivers/media/video/m52790.c
new file mode 100644
index 0000000..51ecbfb
--- /dev/null
+++ b/drivers/media/video/m52790.c
@@ -0,0 +1,172 @@
+/*
+ * m52790 i2c ivtv driver.
+ * Copyright (C) 2007  Hans Verkuil
+ *
+ * A/V source switching Mitsubishi M52790SP/FP
+ *
+ * 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
+ * (at your option) 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/ioctl.h>
+#include <asm/uaccess.h>
+#include <linux/i2c.h>
+#include <linux/i2c-id.h>
+#include <linux/videodev.h>
+#include <media/m52790.h>
+#include <media/v4l2-common.h>
+#include <media/v4l2-chip-ident.h>
+#include <media/v4l2-i2c-drv-legacy.h>
+
+MODULE_DESCRIPTION("i2c device driver for m52790 A/V switch");
+MODULE_AUTHOR("Hans Verkuil");
+MODULE_LICENSE("GPL");
+
+static unsigned short normal_i2c[] = { 0x90 >> 1, I2C_CLIENT_END };
+
+
+I2C_CLIENT_INSMOD;
+
+struct m52790_state {
+	u16 input;
+	u16 output;
+};
+
+/* ----------------------------------------------------------------------- */
+
+static int m52790_write(struct i2c_client *client)
+{
+	struct m52790_state *state = i2c_get_clientdata(client);
+	u8 sw1 = (state->input | state->output) & 0xff;
+	u8 sw2 = (state->input | state->output) >> 8;
+
+	return i2c_smbus_write_byte_data(client, sw1, sw2);
+}
+
+static int m52790_command(struct i2c_client *client, unsigned int cmd,
+			    void *arg)
+{
+	struct m52790_state *state = i2c_get_clientdata(client);
+	struct v4l2_routing *route = arg;
+
+	/* Note: audio and video are linked and cannot be switched separately.
+	   So audio and video routing commands are identical for this chip.
+	   In theory the video amplifier and audio modes could be handled
+	   separately for the output, but that seems to be overkill right now.
+	   The same holds for implementing an audio mute control, this is now
+	   part of the audio output routing. The normal case is that another
+	   chip takes care of the actual muting so making it part of the
+	   output routing seems to be the right thing to do for now. */
+	switch (cmd) {
+	case VIDIOC_INT_G_AUDIO_ROUTING:
+	case VIDIOC_INT_G_VIDEO_ROUTING:
+		route->input = state->input;
+		route->output = state->output;
+		break;
+
+	case VIDIOC_INT_S_AUDIO_ROUTING:
+	case VIDIOC_INT_S_VIDEO_ROUTING:
+		state->input = route->input;
+		state->output = route->output;
+		m52790_write(client);
+		break;
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	case VIDIOC_DBG_G_REGISTER:
+	case VIDIOC_DBG_S_REGISTER:
+	{
+		struct v4l2_register *reg = arg;
+
+		if (!v4l2_chip_match_i2c_client(client,
+					reg->match_type, reg->match_chip))
+			return -EINVAL;
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		if (reg->reg != 0)
+			return -EINVAL;
+		if (cmd == VIDIOC_DBG_G_REGISTER)
+			reg->val = state->input | state->output;
+		else {
+			state->input = reg->val & 0x0303;
+			state->output = reg->val & ~0x0303;
+			m52790_write(client);
+		}
+		break;
+	}
+#endif
+
+	case VIDIOC_G_CHIP_IDENT:
+		return v4l2_chip_ident_i2c_client(client, arg,
+				V4L2_IDENT_M52790, 0);
+
+	case VIDIOC_LOG_STATUS:
+		v4l_info(client, "Switch 1: %02x\n",
+				(state->input | state->output) & 0xff);
+		v4l_info(client, "Switch 2: %02x\n",
+				(state->input | state->output) >> 8);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+
+/* i2c implementation */
+
+static int m52790_probe(struct i2c_client *client)
+{
+	struct m52790_state *state;
+
+	/* Check if the adapter supports the needed features */
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -EIO;
+
+	snprintf(client->name, sizeof(client->name) - 1, "m52790");
+
+	v4l_info(client, "chip found @ 0x%x (%s)\n",
+			client->addr << 1, client->adapter->name);
+
+	state = kmalloc(sizeof(struct m52790_state), GFP_KERNEL);
+	if (state == NULL)
+		return -ENOMEM;
+
+	state->input = M52790_IN_TUNER;
+	state->output = M52790_OUT_STEREO;
+	i2c_set_clientdata(client, state);
+	m52790_write(client);
+	return 0;
+}
+
+static int m52790_remove(struct i2c_client *client)
+{
+	kfree(i2c_get_clientdata(client));
+	return 0;
+}
+
+/* ----------------------------------------------------------------------- */
+
+static struct v4l2_i2c_driver_data v4l2_i2c_data = {
+	.name = "m52790",
+	.driverid = I2C_DRIVERID_M52790,
+	.command = m52790_command,
+	.probe = m52790_probe,
+	.remove = m52790_remove,
+};
+