From 0749f646c3b47b0980716776ccd19158320931a3 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@free-electrons.com>
Date: Tue, 18 Sep 2018 10:35:29 +0300
Subject: [PATCH] W1-EEPROM: add support for Maxim DS24 eeprom families

Add a driver that supports Maxim 1 wire EEPROMs families
DS24B33 and DS2431.
Can be extended for other families as well.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
[eugen.hristev@microchip.com: reworked driver]
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
---
 drivers/w1-eeprom/Kconfig   |  6 +++++
 drivers/w1-eeprom/Makefile  |  2 ++
 drivers/w1-eeprom/ds24xxx.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+)
 create mode 100644 drivers/w1-eeprom/ds24xxx.c

diff --git a/drivers/w1-eeprom/Kconfig b/drivers/w1-eeprom/Kconfig
index d5ddc80..20ec549 100644
--- a/drivers/w1-eeprom/Kconfig
+++ b/drivers/w1-eeprom/Kconfig
@@ -12,6 +12,12 @@ config W1_EEPROM
 
 if W1_EEPROM
 
+config W1_EEPROM_DS24XXX
+	bool "Enable Maxim DS24 families EEPROM support"
+	depends on W1
+	help
+	  Maxim DS24 EEPROMs 1-Wire EEPROM support
+
 endif
 
 endmenu
diff --git a/drivers/w1-eeprom/Makefile b/drivers/w1-eeprom/Makefile
index b72950e..3f4aa13 100644
--- a/drivers/w1-eeprom/Makefile
+++ b/drivers/w1-eeprom/Makefile
@@ -1,2 +1,4 @@
 obj-$(CONFIG_W1_EEPROM) += w1-eeprom-uclass.o
 
+obj-$(CONFIG_W1_EEPROM_DS24XXX) += ds24xxx.o
+
diff --git a/drivers/w1-eeprom/ds24xxx.c b/drivers/w1-eeprom/ds24xxx.c
new file mode 100644
index 0000000..56186e5
--- /dev/null
+++ b/drivers/w1-eeprom/ds24xxx.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier:	GPL-2.0+
+/*
+ *
+ * Copyright (c) 2015 Free Electrons
+ * Copyright (c) 2015 NextThing Co
+ * Copyright (c) 2018 Microchip Technology, Inc.
+ *
+ */
+
+#include <common.h>
+#include <linux/err.h>
+#include <dm.h>
+#include <w1-eeprom.h>
+#include <w1.h>
+
+#define W1_F2D_READ_EEPROM	0xf0
+
+static int ds24xxx_read_buf(struct udevice *dev, unsigned int offset,
+			    u8 *buf, unsigned int count)
+{
+	w1_reset_select(dev);
+
+	w1_write_byte(dev, W1_F2D_READ_EEPROM);
+	w1_write_byte(dev, offset & 0xff);
+	w1_write_byte(dev, offset >> 8);
+
+	return w1_read_buf(dev, buf, count);
+}
+
+static int ds24xxx_probe(struct udevice *dev)
+{
+	struct w1_device *w1;
+
+	w1 = dev_get_platdata(dev);
+	w1->id = 0;
+	return 0;
+}
+
+static const struct w1_eeprom_ops ds24xxx_ops = {
+	.read_buf	= ds24xxx_read_buf,
+};
+
+static const struct udevice_id ds24xxx_id[] = {
+	{ .compatible = "maxim,ds24b33", .data = W1_FAMILY_DS24B33 },
+	{ .compatible = "maxim,ds2431", .data = W1_FAMILY_DS2431 },
+	{ },
+};
+
+U_BOOT_DRIVER(ds24xxx) = {
+	.name		= "ds24xxx",
+	.id		= UCLASS_W1_EEPROM,
+	.of_match	= ds24xxx_id,
+	.ops		= &ds24xxx_ops,
+	.probe		= ds24xxx_probe,
+};