[PATCH 2/2] at24: add I2C eeprom for 24cl02

[Marc Reilly]

This series adds a driver for at24 eeproms. Much of the guts of the code
is taken from the at24 driver in the linux kernel.
The files are located under a new misc directory, as per the kernel also.

Signed-off-by: Marc Reilly <marc at cpdesign.com.au>
---
 drivers/Kconfig       |    1 +
 drivers/Makefile      |    1 +
 drivers/misc/Kconfig  |   10 ++++
 drivers/misc/Makefile |    1 +
 drivers/misc/at24.c   |  130 +++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 143 insertions(+), 0 deletions(-)
 create mode 100644 drivers/misc/Kconfig
 create mode 100644 drivers/misc/Makefile
 create mode 100644 drivers/misc/at24.c

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 86d8fb5..c54e225 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -13,5 +13,6 @@ source "drivers/mci/Kconfig"
 source "drivers/clk/Kconfig"
 source "drivers/mfd/Kconfig"
 source "drivers/led/Kconfig"
+source "drivers/misc/Kconfig"
 
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index b1b402f..2127857 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_VIDEO) += video/
 obj-y	+= clk/
 obj-y	+= mfd/
 obj-$(CONFIG_LED) += led/
+obj-$(CONFIG_MISC) += misc/
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
new file mode 100644
index 0000000..7da647f
--- /dev/null
+++ b/drivers/misc/Kconfig
@@ -0,0 +1,10 @@
+menuconfig MISC
+	bool "Misc devices support"
+
+if MISC
+
+config AT24
+	bool "at24 based eeprom"
+	depends on I2C
+
+endif
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
new file mode 100644
index 0000000..45d6553
--- /dev/null
+++ b/drivers/misc/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_AT24) += at24.o
diff --git a/drivers/misc/at24.c b/drivers/misc/at24.c
new file mode 100644
index 0000000..7bb085a
--- /dev/null
+++ b/drivers/misc/at24.c
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2007 Sascha Hauer, Pengutronix
+ *               2009 Marc Kleine-Budde <mkl at pengutronix.de>
+ *               2010 Marc Reilly, Creative Product Design
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <xfuncs.h>
+#include <errno.h>
+
+#include <i2c/i2c.h>
+#include <misc/at24.h>
+
+#define DRIVERNAME		"at24"
+
+#define to_at24(a)		container_of(a, struct at24, cdev)
+
+static ssize_t at24_read(struct cdev *cdev, void *_buf, size_t count,
+		ulong offset, ulong flags)
+{
+	struct at24 *priv = to_at24(cdev);
+	u8 *buf = _buf;
+	size_t i = count;
+	ssize_t numwritten = 0;
+	int retries = 5;
+	int ret;
+
+	while (i && retries) {
+		ret = i2c_read_reg(priv->client, offset, buf, i);
+		if (ret < 0)
+			return (ssize_t)ret;
+		else if (ret == 0)
+			--retries;
+
+		numwritten += ret;
+		i -= ret;
+		offset += ret;
+		buf += ret;
+	}
+
+	return numwritten;
+}
+
+static ssize_t at24_write(struct cdev *cdev, const void *_buf, size_t count,
+		ulong offset, ulong flags)
+{
+	struct at24 *priv = to_at24(cdev);
+	const u8 *buf = _buf;
+	const int maxwrite = 8;
+	int numtowrite;
+	ssize_t numwritten = 0;
+
+	while (count) {
+		int ret;
+
+		numtowrite = count;
+		if (numtowrite > maxwrite)
+			numtowrite = maxwrite;
+
+		ret = i2c_write_reg(priv->client, offset, buf, numtowrite);
+		if (ret < 0)
+			return (ssize_t)ret;
+
+		mdelay(10);
+
+		numwritten += ret;
+		buf += ret;
+		count -= ret;
+		offset += ret;
+	}
+
+	return numwritten;
+}
+
+static struct file_operations at24_fops = {
+	.lseek	= dev_lseek_default,
+	.read	= at24_read,
+	.write	= at24_write,
+};
+
+static int at24_probe(struct device_d *dev)
+{
+	struct at24 *at24;
+	struct at24_platform_data *pdata;
+	at24 = xzalloc(sizeof(*at24));
+
+	dev->priv = at24;
+	pdata = dev->platform_data;
+
+	at24->cdev.name = DRIVERNAME;
+	at24->client = to_i2c_client(dev);
+	at24->cdev.size = pdata->size;
+	at24->cdev.dev = dev;
+	at24->cdev.ops = &at24_fops;
+
+	devfs_create(&at24->cdev);
+
+	return 0;
+}
+
+static struct driver_d at24_driver = {
+	.name  = DRIVERNAME,
+	.probe = at24_probe,
+};
+
+static int at24_init(void)
+{
+	register_driver(&at24_driver);
+	return 0;
+}
+
+device_initcall(at24_init);
-- 
1.7.1