[PATCH 14/28] drm/via: Add via_i2c.c

From: Kevin Brace <kevinbrace@gmx.com>
To: dri-devel@lists.freedesktop.org
Cc: Kevin Brace <kevinbrace@bracecomputerlab.com>
Subject: [PATCH 14/28] drm/via: Add via_i2c.c
Date: Fri, 24 Jun 2022 15:26:19 -0500	[thread overview]
Message-ID: <20220624202633.3978-15-kevinbrace@gmx.com> (raw)
In-Reply-To: <20220624202633.3978-1-kevinbrace@gmx.com>

From: Kevin Brace <kevinbrace@bracecomputerlab.com>

Note that the code here is GPL based.

Signed-off-by: Kevin Brace <kevinbrace@bracecomputerlab.com>
---
 drivers/gpu/drm/via/via_i2c.c | 209 ++++++++++++++++++++++++++++++++++
 1 file changed, 209 insertions(+)
 create mode 100644 drivers/gpu/drm/via/via_i2c.c

diff --git a/drivers/gpu/drm/via/via_i2c.c b/drivers/gpu/drm/via/via_i2c.c
new file mode 100644
index 000000000000..f2e8b118754e
--- /dev/null
+++ b/drivers/gpu/drm/via/via_i2c.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2012 James Simmons. All Rights Reserved.
+ * Copyright 1998-2009 VIA Technologies, Inc. All Rights Reserved.
+ * Copyright 2001-2008 S3 Graphics, Inc. All Rights Reserved.
+ *
+ * Author(s):
+ * James Simmons <jsimmons@infradead.org>
+ */
+
+#include <linux/delay.h>
+
+#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_setsda(void *data, int state)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct via_drm_priv *dev_priv = to_via_drm_priv(dev);
+	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) | BIT(0) : BIT(0);
+		mask = BIT(4) | BIT(0);
+	}
+
+	svga_wseq_mask(VGABASE, i2c->i2c_port, value, mask);
+}
+
+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 via_drm_priv *dev_priv = to_via_drm_priv(dev);
+	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) | BIT(0) : BIT(0);
+		mask = BIT(5) | BIT(0);
+	}
+
+	svga_wseq_mask(VGABASE, i2c->i2c_port, value, mask);
+}
+
+static int via_i2c_getsda(void *data)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct via_drm_priv *dev_priv = to_via_drm_priv(dev);
+
+	return vga_rseq(VGABASE, i2c->i2c_port) & BIT(2);
+}
+
+static int via_i2c_getscl(void *data)
+{
+	struct via_i2c_stuff *i2c = data;
+	struct drm_device *dev = i2c_get_adapdata(&i2c->adapter);
+	struct via_drm_priv *dev_priv = to_via_drm_priv(dev);
+
+	return vga_rseq(VGABASE, i2c->i2c_port) & BIT(3);
+}
+
+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);
+}
+
+void via_i2c_reg_init(struct via_drm_priv *dev_priv)
+{
+	svga_wseq_mask(VGABASE, 0x31, 0x30, 0x30);
+	svga_wseq_mask(VGABASE, 0x26, 0x30, 0x30);
+	vga_wseq(VGABASE, 0x2C, 0xc2);
+	vga_wseq(VGABASE, 0x3D, 0xc0);
+	svga_wseq_mask(VGABASE, 0x2C, 0x30, 0x30);
+	svga_wseq_mask(VGABASE, 0x3D, 0x30, 0x30);
+}
+
+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);
+}
--
2.35.1

