[U-Boot] [PATCH 04/20] W1-EEPROM: Add an W1-EEPROM uclass for 1 wire EEPROMs

[Eugen Hristev]

From: Maxime Ripard <maxime.ripard at free-electrons.com>

We might want to access data stored onto one wire EEPROMs.
Create a framework to provide a consistent API.

Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
[eugen.hristev at microchip.com: reworked patch]
Signed-off-by: Eugen Hristev <eugen.hristev at microchip.com>
---
 drivers/Kconfig                      |  2 ++
 drivers/Makefile                     |  1 +
 drivers/w1-eeprom/Kconfig            | 17 +++++++++++
 drivers/w1-eeprom/Makefile           |  2 ++
 drivers/w1-eeprom/w1-eeprom-uclass.c | 56 ++++++++++++++++++++++++++++++++++++
 include/dm/uclass-id.h               |  1 +
 include/w1-eeprom.h                  | 28 ++++++++++++++++++
 7 files changed, 107 insertions(+)
 create mode 040000 drivers/w1-eeprom
 create mode 100644 drivers/w1-eeprom/Kconfig
 create mode 100644 drivers/w1-eeprom/Makefile
 create mode 100644 drivers/w1-eeprom/w1-eeprom-uclass.c
 create mode 100644 include/w1-eeprom.h

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 2cae829..386af75 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -104,6 +104,8 @@ source "drivers/video/Kconfig"
 
 source "drivers/w1/Kconfig"
 
+source "drivers/w1-eeprom/Kconfig"
+
 source "drivers/watchdog/Kconfig"
 
 config PHYS_TO_BUS
diff --git a/drivers/Makefile b/drivers/Makefile
index 728380b..de67a17 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -102,6 +102,7 @@ obj-y += soc/
 obj-$(CONFIG_REMOTEPROC) += remoteproc/
 obj-y += thermal/
 obj-$(CONFIG_W1) += w1/
+obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
 
 obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
 endif
diff --git a/drivers/w1-eeprom/Kconfig b/drivers/w1-eeprom/Kconfig
new file mode 100644
index 0000000..d5ddc80
--- /dev/null
+++ b/drivers/w1-eeprom/Kconfig
@@ -0,0 +1,17 @@
+#
+# EEPROM subsystem configuration
+#
+
+menu "1-wire EEPROM support"
+
+config W1_EEPROM
+	bool "Enable support for EEPROMs on 1wire interface"
+	depends on DM
+	help
+	  Support for the EEPROMs connected on 1-wire Dallas protocol interface
+
+if W1_EEPROM
+
+endif
+
+endmenu
diff --git a/drivers/w1-eeprom/Makefile b/drivers/w1-eeprom/Makefile
new file mode 100644
index 0000000..b72950e
--- /dev/null
+++ b/drivers/w1-eeprom/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_W1_EEPROM) += w1-eeprom-uclass.o
+
diff --git a/drivers/w1-eeprom/w1-eeprom-uclass.c b/drivers/w1-eeprom/w1-eeprom-uclass.c
new file mode 100644
index 0000000..4176baf
--- /dev/null
+++ b/drivers/w1-eeprom/w1-eeprom-uclass.c
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co.
+ *
+ * Maxime Ripard <maxime.ripard at free-electrons.com>
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <w1-eeprom.h>
+
+#include <dm/device-internal.h>
+
+int w1_eeprom_read_buf(struct udevice *dev, unsigned int offset,
+		       u8 *buf, unsigned int count)
+{
+	const struct w1_eeprom_ops *ops = device_get_ops(dev);
+
+	if (!ops->read_buf)
+		return -ENOSYS;
+
+	return ops->read_buf(dev, offset, buf, count);
+}
+
+UCLASS_DRIVER(w1_eeprom) = {
+	.name		= "w1_eeprom",
+	.id		= UCLASS_W1_EEPROM,
+};
+
+int w1_eeprom_dm_init(void)
+{
+	struct udevice *bus;
+	struct uclass *uc;
+	int ret;
+
+	ret = uclass_get(UCLASS_W1_EEPROM, &uc);
+	if (ret)
+		return ret;
+
+	uclass_foreach_dev(bus, uc) {
+		ret = device_probe(bus);
+		if (ret == -ENODEV) {	/* No such device. */
+			debug("W1_EEPROM not available.\n");
+			continue;
+		}
+
+		if (ret) {		/* Other error. */
+			printf("W1_EEPROM probe failed, error %d\n", ret);
+			continue;
+		}
+	}
+
+	return 0;
+}
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 8eca9dc..06ff339 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -90,6 +90,7 @@ enum uclass_id {
 	UCLASS_VIDEO_BRIDGE,	/* Video bridge, e.g. DisplayPort to LVDS */
 	UCLASS_VIDEO_CONSOLE,	/* Text console driver for video device */
 	UCLASS_W1,		/* Dallas 1-Wire bus */
+	UCLASS_W1_EEPROM,	/* one-wire EEPROMs */
 	UCLASS_WDT,		/* Watchdot Timer driver */
 
 	UCLASS_COUNT,
diff --git a/include/w1-eeprom.h b/include/w1-eeprom.h
new file mode 100644
index 0000000..7c9dd96
--- /dev/null
+++ b/include/w1-eeprom.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier:	GPL-2.0+
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co
+ * Copyright (c) 2018 Microchip Technology, Inc.
+ *
+ */
+
+#ifndef __W1_EEPROM_H
+#define __W1_EEPROM_H
+
+struct udevice;
+
+struct w1_eeprom_ops {
+	/*
+	 * Reads a buff from the given EEPROM memory, starting at
+	 * given offset and place the results into the given buffer.
+	 * Should read given count of bytes.
+	 * Should return 0 on success, and normal error.h on error
+	 */
+	int	(*read_buf)(struct udevice *dev, unsigned int offset,
+			    u8 *buf, unsigned int count);
+};
+
+int w1_eeprom_read_buf(struct udevice *dev, unsigned int offset,
+		       u8 *buf, unsigned int count);
+
+#endif
-- 
2.7.4