lib: utils/i2c: Add generic I2C configuration library

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

Tested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Tested-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>

diff --git a/include/sbi_utils/i2c/i2c.h b/include/sbi_utils/i2c/i2c.h
new file mode 100644 (file)
index 0000000..5a70364
--- /dev/null
+++ b/include/sbi_utils/i2c/i2c.h
@@ -0,0 +1,85 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 YADRO
+ *
+ * Authors:
+ *   Nikita Shubin <n.shubin@yadro.com>
+ */
+
+#ifndef __I2C_H__
+#define __I2C_H__
+
+#include <sbi/sbi_types.h>
+#include <sbi/sbi_list.h>
+
+/** Representation of a I2C adapter */
+struct i2c_adapter {
+       /** Pointer to I2C driver owning this I2C adapter */
+       void *driver;
+
+       /** Unique ID of the I2C adapter assigned by the driver */
+       int id;
+
+       /**
+        * Send buffer to given address, register
+        *
+        * @return 0 on success and negative error code on failure
+        */
+       int (*write)(struct i2c_adapter *ia, uint8_t addr, uint8_t reg,
+                   uint8_t *buffer, int len);
+
+       /**
+        * Read buffer 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 *buffer, int len);
+
+       /** List */
+       struct sbi_dlist node;
+};
+
+static inline struct i2c_adapter *to_i2c_adapter(struct sbi_dlist *node)
+{
+       return container_of(node, struct i2c_adapter, node);
+}
+
+/** 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);
+
+/** Send to device on I2C adapter bus */
+int i2c_adapter_write(struct i2c_adapter *ia, uint8_t addr, uint8_t reg,
+                     uint8_t *buffer, int len);
+
+/** Read from device on I2C adapter bus */
+int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr, uint8_t reg,
+                    uint8_t *buffer, int len);
+
+static inline int i2c_adapter_reg_write(struct i2c_adapter *ia, uint8_t addr,
+                                uint8_t reg, uint8_t val)
+{
+       return i2c_adapter_write(ia, addr, reg, &val, 1);
+}
+
+static inline int i2c_adapter_reg_read(struct i2c_adapter *ia, uint8_t addr,
+                                      uint8_t reg, uint8_t *val)
+{
+       uint8_t buf;
+       int ret = i2c_adapter_read(ia, addr, reg, &buf, 1);
+
+       if (ret)
+               return ret;
+
+       *val = buf;
+       return 0;
+}
+
+#endif

diff --git a/lib/utils/i2c/i2c.c b/lib/utils/i2c/i2c.c
new file mode 100644 (file)
index 0000000..6be4e24
--- /dev/null
+++ b/lib/utils/i2c/i2c.c
@@ -0,0 +1,75 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2021 YADRO
+ *
+ * Authors:
+ *   Nikita Shubin <n.shubin@yadro.com>
+ *
+ * derivate: lib/utils/gpio/gpio.c
+ * Authors:
+ *   Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <sbi/sbi_error.h>
+#include <sbi_utils/i2c/i2c.h>
+
+static SBI_LIST_HEAD(i2c_adapters_list);
+
+struct i2c_adapter *i2c_adapter_find(int id)
+{
+       struct sbi_dlist *pos;
+
+       sbi_list_for_each(pos, &(i2c_adapters_list)) {
+               struct i2c_adapter *adap = to_i2c_adapter(pos);
+
+               if (adap->id == id)
+                       return adap;
+       }
+
+       return NULL;
+}
+
+int i2c_adapter_add(struct i2c_adapter *ia)
+{
+       if (!ia)
+               return SBI_EINVAL;
+
+       if (i2c_adapter_find(ia->id))
+               return SBI_EALREADY;
+
+       sbi_list_add(&(ia->node), &(i2c_adapters_list));
+
+       return 0;
+}
+
+void i2c_adapter_remove(struct i2c_adapter *ia)
+{
+       if (!ia)
+               return;
+
+       sbi_list_del(&(ia->node));
+}
+
+int i2c_adapter_write(struct i2c_adapter *ia, uint8_t addr, uint8_t reg,
+                    uint8_t *buffer, int len)
+{
+       if (!ia)
+               return SBI_EINVAL;
+       if (!ia->write)
+               return SBI_ENOSYS;
+
+       return ia->write(ia, addr, reg, buffer, len);
+}
+
+
+int i2c_adapter_read(struct i2c_adapter *ia, uint8_t addr, uint8_t reg,
+                    uint8_t *buffer, int len)
+{
+       if (!ia)
+               return SBI_EINVAL;
+       if (!ia->read)
+               return SBI_ENOSYS;
+
+       return ia->read(ia, addr, reg, buffer, len);
+}

diff --git a/lib/utils/i2c/objects.mk b/lib/utils/i2c/objects.mk
new file mode 100644 (file)
index 0000000..894f618
--- /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 <n.shubin@yadro.com>
+#
+
+libsbiutils-objs-y += i2c/i2c.o