[RFC 7/21] DRM: Add VIA DRM driver

[James Simmons]

commit a1296bc36bbc68963ef0294e94bef69ddb998c9a
Author: James Simmons <jsimmons at infradead.org>
Date:   Sat Jun 8 08:53:44 2013 -0400

    via: i2c handling
    
    In order to support EDID retrieval and the via camera on the XO data
    much be collected over the i2c buses. We use the i2c layer developed
    by the viafb project.
    
    Signed-Off-by: James Simmons <jsimmons at infradead.org>

diff --git a/drivers/gpu/drm/via/via_i2c.c b/drivers/gpu/drm/via/via_i2c.c
new file mode 100644
index 0000000..f4fcdea
--- /dev/null
+++ b/drivers/gpu/drm/via/via_i2c.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright 2012 James Simmons <jsimmons at infradead.org> All Rights Reserved.
+ *
+ * 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.
+ *
+ * This part was influenced by the via i2c code written for the viafb
+ * driver by VIA Technologies and S3 Graphics
+ */
+#include "via_drv.h"
+
+enum viafb_i2c_adap;
+
+#include <linux/via_i2c.h>
+
+#define SERIAL	0
+#define	GPIO	1
+
+static struct via_i2c_stuff via_i2c_par[5];
+
+static void via_i2c_setscl(void *data, int state)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct drm_via_private *dev_priv = dev->dev_private;
+	u8 value, mask;
+
+	if (i2c->is_active == GPIO) {
+		mask = state ? BIT(7) : BIT(7) | BIT(5);
+		value = state ? 0x00 : BIT(7);
+	} else {
+		value = state ? BIT(5) : 0x00;
+		mask = BIT(5);
+	}
+	svga_wseq_mask(VGABASE, i2c->i2c_port, value, mask);
+}
+
+static int via_i2c_getscl(void *data)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct drm_via_private *dev_priv = dev->dev_private;
+
+	return (vga_rseq(VGABASE, i2c->i2c_port) & BIT(3));
+}
+
+static int via_i2c_getsda(void *data)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct drm_via_private *dev_priv = dev->dev_private;
+
+	return (vga_rseq(VGABASE, i2c->i2c_port) & BIT(2));
+}
+
+static void via_i2c_setsda(void *data, int state)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct drm_via_private *dev_priv = dev->dev_private;
+	u8 value, mask;
+
+	if (i2c->is_active == GPIO) {
+		mask = state ? BIT(6) : BIT(6) | BIT(4);
+		value = state ? 0x00 : BIT(6);
+	} else {
+		value = state ? BIT(4) : 0x00;
+		mask = BIT(4);
+	}
+	svga_wseq_mask(VGABASE, i2c->i2c_port, value, mask);
+}
+
+struct i2c_adapter *via_find_ddc_bus(int port)
+{
+	struct i2c_adapter *adapter = NULL;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(via_i2c_par); i++) {
+		struct via_i2c_stuff *i2c = &via_i2c_par[i];
+
+		if (i2c->i2c_port == port) {
+			adapter = &i2c->adapter;
+			break;
+		}
+	}
+	return adapter;
+}
+
+static int
+create_i2c_bus(struct drm_device *dev, struct via_i2c_stuff *i2c_par)
+{
+	struct i2c_adapter *adapter = &i2c_par->adapter;
+	struct i2c_algo_bit_data *algo = &i2c_par->algo;
+
+	algo->setsda = via_i2c_setsda;
+	algo->setscl = via_i2c_setscl;
+	algo->getsda = via_i2c_getsda;
+	algo->getscl = via_i2c_getscl;
+	algo->udelay = 15;
+	algo->timeout = usecs_to_jiffies(2200); /* from VESA */
+	algo->data = i2c_par;
+
+	sprintf(adapter->name, "via i2c bit bus 0x%02x", i2c_par->i2c_port);
+	adapter->owner = THIS_MODULE;
+	adapter->class = I2C_CLASS_DDC;
+	adapter->algo_data = algo;
+	i2c_set_adapdata(adapter, dev);
+
+	/* Raise SCL and SDA */
+	via_i2c_setsda(i2c_par, 1);
+	via_i2c_setscl(i2c_par, 1);
+	udelay(20);
+
+	return i2c_bit_add_bus(adapter);
+}
+
+void
+via_i2c_readbytes(struct i2c_adapter *adapter,
+			u8 slave_addr, char offset,
+			u8 *buffer, unsigned int size)
+{
+	u8 out_buf[2];
+	u8 in_buf[2];
+	struct i2c_msg msgs[] = {
+		{
+			.addr = slave_addr,
+			.flags = 0,
+			.len = 1,
+			.buf = out_buf,
+		},
+		{
+			.addr = slave_addr,
+			.flags = I2C_M_RD,
+			.len = size,
+			.buf = in_buf,
+		}
+	};
+
+	out_buf[0] = offset;
+	out_buf[1] = 0;
+
+	if (i2c_transfer(adapter, msgs, 2) != 2)
+		printk(KERN_WARNING "%s failed\n", __func__);
+	else
+		*buffer = in_buf[0];
+}
+
+void
+via_i2c_writebytes(struct i2c_adapter *adapter,
+			u8 slave_addr, char offset,
+			u8 *data, unsigned int size)
+{
+	struct i2c_msg msg = { 0 };
+	u8 *out_buf;
+
+	out_buf = kzalloc(size + 1, GFP_KERNEL);
+	out_buf[0] = offset;
+	memcpy(&out_buf[1], data, size);
+	msg.addr = slave_addr;
+	msg.flags = 0;
+	msg.len = size + 1;
+	msg.buf = out_buf;
+
+	if (i2c_transfer(adapter, &msg, 1) != 1)
+		printk(KERN_WARNING "%s failed\n", __func__);
+
+	kfree(out_buf);
+}
+
+int via_i2c_init(struct drm_device *dev)
+{
+	int types[] = { SERIAL, SERIAL, GPIO, GPIO, GPIO };
+	int ports[] = { 0x26, 0x31, 0x25, 0x2C, 0x3D };
+	int count = ARRAY_SIZE(via_i2c_par), ret, i;
+	struct via_i2c_stuff *i2c = via_i2c_par;
+
+	for (i = 0; i < count; i++) {
+		i2c->is_active = types[i];
+		i2c->i2c_port = ports[i];
+
+		ret = create_i2c_bus(dev, i2c);
+		if (ret < 0)
+			DRM_ERROR("cannot create i2c bus %x:%d\n",
+					ports[i], ret);
+		i2c++;
+	}
+	return 0;
+}
+
+void via_i2c_exit(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(via_i2c_par); i++)
+		i2c_del_adapter(&via_i2c_par->adapter);
+}