W1-EEPROM: Add an W1-EEPROM uclass for 1 wire EEPROMs

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@bootlin.com>
[eugen.hristev@microchip.com: reworked patch]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>

drivers/Kconfig

@@ -108,6 +108,8 @@ source "drivers/video/Kconfig"
 
 source "drivers/w1/Kconfig"
 
+source "drivers/w1-eeprom/Kconfig"
+
 source "drivers/watchdog/Kconfig"
 
 config PHYS_TO_BUS

drivers/Makefile

@@ -106,6 +106,7 @@ obj-y += soc/
 obj-y += thermal/
 obj-y += axi/
 obj-$(CONFIG_W1) += w1/
+obj-$(CONFIG_W1_EEPROM) += w1-eeprom/
 
 obj-$(CONFIG_MACH_PIC32) += ddr/microchip/
 endif

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

drivers/w1-eeprom/Makefile

@@ -0,0 +1,2 @@
+obj-$(CONFIG_W1_EEPROM) += w1-eeprom-uclass.o
+

drivers/w1-eeprom/w1-eeprom-uclass.c

@@ -0,0 +1,116 @@
+// SPDX-License-Identifier:	GPL-2.0+
+/*
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co.
+ * Copyright (c) 2018 Microchip Technology, Inc.
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ * Eugen Hristev <eugen.hristev@microchip.com>
+ *
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <w1.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);
+	u64 id = 0;
+	int ret;
+
+	if (!ops->read_buf)
+		return -ENOSYS;
+
+	ret = w1_eeprom_get_id(dev, &id);
+	if (ret)
+		return ret;
+	if (!id)
+		return -ENODEV;
+
+	return ops->read_buf(dev, offset, buf, count);
+}
+
+int w1_eeprom_register_new_device(u64 id)
+{
+	u8 family = id & 0xff;
+	int ret;
+	struct udevice *dev;
+
+	for (ret = uclass_first_device(UCLASS_W1_EEPROM, &dev);
+	     !ret && dev;
+	     uclass_next_device(&dev)) {
+		if (ret || !dev) {
+			debug("cannot find w1 eeprom dev\n");
+			return ret;
+		}
+		if (dev_get_driver_data(dev) == family) {
+			struct w1_device *w1;
+
+			w1 = dev_get_parent_platdata(dev);
+			if (w1->id) /* device already in use */
+				continue;
+			w1->id = id;
+			debug("%s: Match found: %s:%s %llx\n", __func__,
+			      dev->name, dev->driver->name, id);
+			return 0;
+		}
+	}
+
+	debug("%s: No matches found: error %d\n", __func__, ret);
+
+	return ret;
+}
+
+int w1_eeprom_get_id(struct udevice *dev, u64 *id)
+{
+	struct w1_device *w1 = dev_get_parent_platdata(dev);
+
+	if (!w1)
+		return -ENODEV;
+	*id = w1->id;
+
+	return 0;
+}
+
+UCLASS_DRIVER(w1_eeprom) = {
+	.name		= "w1_eeprom",
+	.id		= UCLASS_W1_EEPROM,
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+	.post_bind	= dm_scan_fdt_dev,
+#endif
+};
+
+int w1_eeprom_dm_init(void)
+{
+	struct udevice *dev;
+	struct uclass *uc;
+	int ret;
+
+	ret = uclass_get(UCLASS_W1_EEPROM, &uc);
+	if (ret) {
+		debug("W1_EEPROM uclass not available\n");
+		return ret;
+	}
+
+	uclass_foreach_dev(dev, uc) {
+		ret = device_probe(dev);
+		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;
+}

include/dm/uclass-id.h

@@ -94,6 +94,7 @@ 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,

include/w1-eeprom.h

@@ -0,0 +1,33 @@
+/* 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);
+
+int w1_eeprom_dm_init(void);
+
+int w1_eeprom_register_new_device(u64 id);
+
+int w1_eeprom_get_id(struct udevice *dev, u64 *id);
+#endif