[PATCH 1/4] lib: utils/i2c: Add generic I2C configuration library

[Nikita Shubin]

From: Nikita Shubin <n.shubin at yadro.com>

Helper library to keep track of registered I2C adapters,
identified by dts offset, basic send/read functions and
adapter configuration (enable, set dividers, etc...).

Signed-off-by: Nikita Shubin <n.shubin at yadro.com>
---
 include/sbi_utils/i2c/i2c.h |  65 +++++++++++++++++++++++
 lib/utils/i2c/i2c.c         | 102 ++++++++++++++++++++++++++++++++++++
 lib/utils/i2c/objects.mk    |  10 ++++
 3 files changed, 177 insertions(+)
 create mode 100644 include/sbi_utils/i2c/i2c.h
 create mode 100644 lib/utils/i2c/i2c.c
 create mode 100644 lib/utils/i2c/objects.mk

diff --git a/include/sbi_utils/i2c/i2c.h b/include/sbi_utils/i2c/i2c.h
new file mode 100644
index 0000000..86dd582
--- /dev/null
+++ b/include/sbi_utils/i2c/i2c.h
@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 YADRO
+ *
+ * Authors:
+ *   Nikita Shubin <nshubin at yadro.com>
+ */
+
+#ifndef __I2C_H__
+#define __I2C_H__
+
+#include <sbi/sbi_types.h>
+
+/** Representation of a I2C adapter */
+struct i2c_adapter {
+	/** Pointer to I2C driver owning this I2C adapter */
+	void *driver;
+
+	/** Uniquie ID of the I2C adapter assigned by the driver */
+	int id;
+
+	/**
+	 * Configure I2C adapter
+	 *
+	 * Enable, set dividers, etc...
+	 *
+	 * @return 0 on success and negative error code on failure
+	 */
+	int (*configure)(struct i2c_adapter *ia);
+
+	/**
+	 * Send byte to given address, register
+	 *
+	 * @return 0 on success and negative error code on failure
+	 */
+	int (*send)(struct i2c_adapter *ia, uint8_t addr, uint8_t reg, uint8_t value);
+
+	/**
+	 * Read byte from given address, register
+	 *
+	 * @return 0 on success and negative error code on failure
+	 */
+	int (*read)(struct i2c_adapter *ia, uint8_t addr, uint8_t reg, uint8_t *value);
+};
+
+/** Find a registered I2C adapter */
+struct i2c_adapter *i2c_adapter_find(int id);
+
+/** Register I2C adapter */
+int i2c_adapter_add(struct i2c_adapter *ia);
+
+/** Un-register I2C adapter */
+void i2c_adapter_remove(struct i2c_adapter *ia);
+
+/** Configure I2C adapter prior to send/read */
+int i2c_adapter_configure(struct i2c_adapter *ia);
+
+/** Send to device on I2C adapter bus */
+int i2c_adapter_send(struct i2c_adapter *ia, uint8_t addr, uint8_t reg, uint8_t value);
+
+/** Read from device on I2C adapter bus */
+int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr, uint8_t reg, uint8_t *value);
+
+#endif
diff --git a/lib/utils/i2c/i2c.c b/lib/utils/i2c/i2c.c
new file mode 100644
index 0000000..9bcb129
--- /dev/null
+++ b/lib/utils/i2c/i2c.c
@@ -0,0 +1,102 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 YADRO
+ *
+ * Authors:
+ *   Nikita Shubin <nshubin at yadro.com>
+ *
+ * derivate: lib/utils/gpio/gpio.c
+ * Authors:
+ *   Anup Patel <anup.patel at wdc.com>
+ */
+
+#include <sbi/sbi_error.h>
+#include <sbi_utils/i2c/i2c.h>
+
+#define I2C_ADAPTER_MAX		16
+
+static struct i2c_adapter *i2c_array[I2C_ADAPTER_MAX];
+
+struct i2c_adapter *i2c_adapter_find(int id)
+{
+	unsigned int i;
+	struct i2c_adapter *ret = NULL;
+
+	for (i = 0; i < I2C_ADAPTER_MAX; i++) {
+		if (i2c_array[i] && i2c_array[i]->id == id) {
+			ret = i2c_array[i];
+			break;
+		}
+	}
+
+	return ret;
+}
+
+int i2c_adapter_add(struct i2c_adapter *ia)
+{
+	int i, ret = SBI_ENOSPC;
+
+	if (!ia)
+		return SBI_EINVAL;
+	if (i2c_adapter_find(ia->id))
+		return SBI_EALREADY;
+
+	for (i = 0; i < I2C_ADAPTER_MAX; i++) {
+		if (!i2c_array[i]) {
+			i2c_array[i] = ia;
+			ret = 0;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+void i2c_adapter_remove(struct i2c_adapter *ia)
+{
+	int i;
+
+	if (!ia)
+		return;
+
+	for (i = 0; i < I2C_ADAPTER_MAX; i++) {
+		if (i2c_array[i] == ia) {
+			i2c_array[i] = NULL;
+			break;
+		}
+	}
+}
+
+int i2c_adapter_configure(struct i2c_adapter *ia)
+{
+	if (!ia)
+		return SBI_EINVAL;
+	if (!ia->configure)
+		return 0;
+
+	return ia->configure(ia);
+}
+
+int i2c_adapter_send(struct i2c_adapter *ia, uint8_t addr,
+		     uint8_t reg, uint8_t value)
+{
+	if (!ia)
+		return SBI_EINVAL;
+	if (!ia->send)
+		return SBI_ENOSYS;
+
+	return ia->send(ia, addr, reg, value);
+}
+
+
+int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr,
+		     uint8_t reg, uint8_t *value)
+{
+	if (!ia)
+		return SBI_EINVAL;
+	if (!ia->read)
+		return SBI_ENOSYS;
+
+	return ia->read(ia, addr, reg, value);
+}
diff --git a/lib/utils/i2c/objects.mk b/lib/utils/i2c/objects.mk
new file mode 100644
index 0000000..16a70da
--- /dev/null
+++ b/lib/utils/i2c/objects.mk
@@ -0,0 +1,10 @@
+#
+# SPDX-License-Identifier: BSD-2-Clause
+#
+# Copyright (c) 2021 YADRO
+#
+# Authors:
+#   Nikita Shubin <nshubin at yadro.com>
+#
+
+libsbiutils-objs-y += i2c/i2c.o
-- 
2.31.1