viafb: add auxiliary device management infrastructure

This patch adds the basic infrastructure and a few stub drivers for
devices that are connected via I2C busses. The infrastructure will
be used to replace and extend the support that is scattered
throughout viafb. The stub drivers are not very useful yet but they
show how the infrastructure works, provide information about the
chips integrated into a system and maybe gather some testers as it
would be very difficult for a single person to get a sane test
environment.
The only thing this actually does is probing the I2C busses which
will hopefully not cause any regressions.

Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

1 files changed, 87 insertions, 0 deletions

diff --git a/drivers/video/via/via_aux.h b/drivers/video/via/via_aux.h
new file mode 100644
index 000000000000..5a4867a2dcc3
--- /dev/null
+++ b/drivers/video/via/via_aux.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2011 Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
+ *
+ * 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, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTIES OR REPRESENTATIONS; 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.
+ */
+/*
+ * infrastructure for devices connected via I2C
+ */
+
+#ifndef __VIA_AUX_H__
+#define __VIA_AUX_H__
+
+
+#include <linux/list.h>
+#include <linux/i2c.h>
+
+
+struct via_aux_bus {
+	struct i2c_adapter *adap;	/* the I2C device to access the bus */
+	struct list_head drivers;	/* drivers for devices on this bus */
+};
+
+struct via_aux_drv {
+	struct list_head chain;		/* chain to support multiple drivers */
+
+	struct via_aux_bus *bus;	/* the I2C bus used */
+	u8 addr;			/* the I2C slave address */
+
+	const char *name;	/* human readable name of the driver */
+	void *data;		/* private data of this driver */
+};
+
+
+struct via_aux_bus *via_aux_probe(struct i2c_adapter *adap);
+void via_aux_free(struct via_aux_bus *bus);
+
+
+static inline bool via_aux_add(struct via_aux_drv *drv)
+{
+	struct via_aux_drv *data = kmalloc(sizeof(*data), GFP_KERNEL);
+
+	if (!data)
+		return false;
+
+	*data = *drv;
+	list_add_tail(&data->chain, &data->bus->drivers);
+	return true;
+}
+
+static inline bool via_aux_read(struct via_aux_drv *drv, u8 start, u8 *buf,
+	u8 len)
+{
+	struct i2c_msg msg[2] = {
+		{.addr = drv->addr, .flags = 0, .len = 1, .buf = &start},
+		{.addr = drv->addr, .flags = I2C_M_RD, .len = len, .buf = buf} };
+
+	return i2c_transfer(drv->bus->adap, msg, 2) == 2;
+}
+
+
+/* probe functions of existing drivers - should only be called in via_aux.c */
+void via_aux_ch7301_probe(struct via_aux_bus *bus);
+void via_aux_edid_probe(struct via_aux_bus *bus);
+void via_aux_sii164_probe(struct via_aux_bus *bus);
+void via_aux_vt1636_probe(struct via_aux_bus *bus);
+void via_aux_vt1632_probe(struct via_aux_bus *bus);
+void via_aux_vt1631_probe(struct via_aux_bus *bus);
+void via_aux_vt1625_probe(struct via_aux_bus *bus);
+void via_aux_vt1622_probe(struct via_aux_bus *bus);
+void via_aux_vt1621_probe(struct via_aux_bus *bus);
+
+
+#endif /* __VIA_AUX_H__ */