1 files changed, 99 insertions, 0 deletions
diff --git a/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_i2c.c b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_i2c.c
new file mode 100644
index 000000000..410bd019b
--- /dev/null
+++ b/drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_i2c.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Hisilicon Hibmc SoC drm driver
+ *
+ * Based on the bochs drm driver.
+ *
+ * Copyright (c) 2016 Huawei Limited.
+ *
+ * Author:
+ *      Tian Tao <tiantao6@hisilicon.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/pci.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_probe_helper.h>
+
+#include "hibmc_drm_drv.h"
+
+#define GPIO_DATA		0x0802A0
+#define GPIO_DATA_DIRECTION	0x0802A4
+
+#define I2C_SCL_MASK		BIT(0)
+#define I2C_SDA_MASK		BIT(1)
+
+static void hibmc_set_i2c_signal(void *data, u32 mask, int value)
+{
+	struct hibmc_connector *hibmc_connector = data;
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev);
+	u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION);
+
+	if (value) {
+		tmp_dir &= ~mask;
+		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
+	} else {
+		u32 tmp_data = readl(priv->mmio + GPIO_DATA);
+
+		tmp_data &= ~mask;
+		writel(tmp_data, priv->mmio + GPIO_DATA);
+
+		tmp_dir |= mask;
+		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
+	}
+}
+
+static int hibmc_get_i2c_signal(void *data, u32 mask)
+{
+	struct hibmc_connector *hibmc_connector = data;
+	struct hibmc_drm_private *priv = to_hibmc_drm_private(hibmc_connector->base.dev);
+	u32 tmp_dir = readl(priv->mmio + GPIO_DATA_DIRECTION);
+
+	if ((tmp_dir & mask) != mask) {
+		tmp_dir &= ~mask;
+		writel(tmp_dir, priv->mmio + GPIO_DATA_DIRECTION);
+	}
+
+	return (readl(priv->mmio + GPIO_DATA) & mask) ? 1 : 0;
+}
+
+static void hibmc_ddc_setsda(void *data, int state)
+{
+	hibmc_set_i2c_signal(data, I2C_SDA_MASK, state);
+}
+
+static void hibmc_ddc_setscl(void *data, int state)
+{
+	hibmc_set_i2c_signal(data, I2C_SCL_MASK, state);
+}
+
+static int hibmc_ddc_getsda(void *data)
+{
+	return hibmc_get_i2c_signal(data, I2C_SDA_MASK);
+}
+
+static int hibmc_ddc_getscl(void *data)
+{
+	return hibmc_get_i2c_signal(data, I2C_SCL_MASK);
+}
+
+int hibmc_ddc_create(struct drm_device *drm_dev,
+		     struct hibmc_connector *connector)
+{
+	connector->adapter.owner = THIS_MODULE;
+	connector->adapter.class = I2C_CLASS_DDC;
+	snprintf(connector->adapter.name, I2C_NAME_SIZE, "HIS i2c bit bus");
+	connector->adapter.dev.parent = drm_dev->dev;
+	i2c_set_adapdata(&connector->adapter, connector);
+	connector->adapter.algo_data = &connector->bit_data;
+
+	connector->bit_data.udelay = 20;
+	connector->bit_data.timeout = usecs_to_jiffies(2000);
+	connector->bit_data.data = connector;
+	connector->bit_data.setsda = hibmc_ddc_setsda;
+	connector->bit_data.setscl = hibmc_ddc_setscl;
+	connector->bit_data.getsda = hibmc_ddc_getsda;
+	connector->bit_data.getscl = hibmc_ddc_getscl;
+
+	return i2c_bit_add_bus(&connector->adapter);
+}