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Gmane
From: Linus Walleij <linus.walleij <at> stericsson.com>
Subject: [PATCH] MFD AB3100 OTP readout v3
Newsgroups: gmane.linux.kernel
Date: Wednesday 19th August 2009 09:09:28 UTC (over 7 years ago)
This adds the ability to read out OTP (One-Time Programmable)
registers in the AB3100 MFD ASIC. It's a simple sysfs file you
can cat to prompt. The OTP registers of the AB3100 are used to
store various device-unique information such as customer ID,
product flags and the 3GPP standard IMEI (International Mobile
Equipment Indentity) number.

Signed-off-by: Linus Walleij 
Reviewed-by: Samuel Ortiz 
---
ChangeLog v2->v3:
- removed OTP platform subdevice in favor of using the ab3100
  I2C device holder also for the OTP stuff
- I don't quite like this way of doing it, reasons:
  - I really liked the structure where the OTP stuff turns
    up in /sys/bus/platform/ab3100-otp instead of
    /sys/bus/i2c/devices/0-0048 (where the AB3100 core
    device lives) This is more clean for userspace I think.
    Userspace users may not be so very interested in having
    to know which I2C address the chip is currently using,
    when all it wants to do is read out some sysfs entries.
  - I really liked not having to expose the ab3100_otp
    struct outside drivers/mfd/ab3100-otp.c now it has to
    go into include/linux/mfd/ab3100.h so I can pass
    pointers around
- I recommend using v2 instead but I can live with this :-)
---
 drivers/mfd/Kconfig        |    9 ++
 drivers/mfd/Makefile       |    1 +
 drivers/mfd/ab3100-core.c  |   12 ++-
 drivers/mfd/ab3100-otp.c   |  203
++++++++++++++++++++++++++++++++++++++++++++
 drivers/mfd/ab3100-otp.h   |   21 +++++
 include/linux/mfd/ab3100.h |   36 ++++++++
 6 files changed, 280 insertions(+), 2 deletions(-)
 create mode 100644 drivers/mfd/ab3100-otp.c
 create mode 100644 drivers/mfd/ab3100-otp.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 491ac0f..fc3eab5 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -256,6 +256,15 @@ config AB3100_CORE
 	  LEDs, vibrator, system power and temperature, power management
 	  and ALSA sound.
 
+config AB3100_OTP
+	tristate "ST-Ericsson AB3100 OTP functions"
+	depends on AB3100_CORE
+	default y if AB3100_CORE
+	help
+	  Select this to enable the AB3100 Mixed Signal IC OTP (one-time
+	  programmable memory) support. This exposes a sysfs file to read
+	  out OTP values.
+
 config EZX_PCAP
 	bool "PCAP Support"
 	depends on GENERIC_HARDIRQS && SPI_MASTER
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 6f8a9a1..b61e5c9 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -44,3 +44,4 @@ obj-$(CONFIG_MFD_PCF50633)	+= pcf50633-core.o
 obj-$(CONFIG_PCF50633_ADC)	+= pcf50633-adc.o
 obj-$(CONFIG_PCF50633_GPIO)	+= pcf50633-gpio.o
 obj-$(CONFIG_AB3100_CORE)	+= ab3100-core.o
+obj-$(CONFIG_AB3100_OTP)	+= ab3100-otp.o
diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
index 098e825..31af242 100644
--- a/drivers/mfd/ab3100-core.c
+++ b/drivers/mfd/ab3100-core.c
@@ -19,6 +19,7 @@
 #include 
 #include 
 #include 
+#include "ab3100-otp.h"
 
 /* These are the only registers inside AB3100 used in this main file */
 
@@ -754,7 +755,6 @@ AB3100_DEVICE(boost, "ab3100-boost");
 AB3100_DEVICE(adc, "ab3100-adc");
 AB3100_DEVICE(fuelgauge, "ab3100-fuelgauge");
 AB3100_DEVICE(vibrator, "ab3100-vibrator");
-AB3100_DEVICE(otp, "ab3100-otp");
 AB3100_DEVICE(codec, "ab3100-codec");
 
 static struct platform_device *
@@ -771,7 +771,6 @@ ab3100_platform_devs[] = {
 	&ab3100_adc_device,
 	&ab3100_fuelgauge_device,
 	&ab3100_vibrator_device,
-	&ab3100_otp_device,
 	&ab3100_codec_device,
 };
 
@@ -917,6 +916,11 @@ static int __init ab3100_probe(struct i2c_client
*client,
 	if (err)
 		goto exit_no_irq;
 
+	/* Initialize OTP driver */
+	err = ab3100_otp_init(ab3100);
+	if (err)
+		goto exit_no_otp;
+
 	/* Set parent and a pointer back to the container in device data */
 	for (i = 0; i < ARRAY_SIZE(ab3100_platform_devs); i++) {
 		ab3100_platform_devs[i]->dev.parent =
@@ -924,6 +928,7 @@ static int __init ab3100_probe(struct i2c_client
*client,
 		platform_set_drvdata(ab3100_platform_devs[i], ab3100);
 	}
 
+
 	/* Register the platform devices */
 	platform_add_devices(ab3100_platform_devs,
 			     ARRAY_SIZE(ab3100_platform_devs));
@@ -932,6 +937,8 @@ static int __init ab3100_probe(struct i2c_client
*client,
 
 	return 0;
 
+ exit_no_otp:
+	free_irq(client->irq, ab3100);
  exit_no_irq:
  exit_no_setup:
 	i2c_unregister_device(ab3100->testreg_client);
@@ -951,6 +958,7 @@ static int __exit ab3100_remove(struct i2c_client
*client)
 		platform_device_unregister(ab3100_platform_devs[i]);
 
 	ab3100_remove_debugfs();
+	ab3100_otp_exit(ab3100);
 	i2c_unregister_device(ab3100->testreg_client);
 
 	/*
diff --git a/drivers/mfd/ab3100-otp.c b/drivers/mfd/ab3100-otp.c
new file mode 100644
index 0000000..2a59d37
--- /dev/null
+++ b/drivers/mfd/ab3100-otp.c
@@ -0,0 +1,203 @@
+/*
+ * drivers/mfd/ab3100-otp.c
+ *
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * Driver to read out OTP from the AB3100 Mixed-signal circuit
+ * Author: Linus Walleij 
+ */
+
+#include 
+#include 
+#include 
+#include "ab3100-otp.h"
+
+/* The OTP registers */
+#define AB3100_OTP0		0xb0
+#define AB3100_OTP1		0xb1
+#define AB3100_OTP2		0xb2
+#define AB3100_OTP3		0xb3
+#define AB3100_OTP4		0xb4
+#define AB3100_OTP5		0xb5
+#define AB3100_OTP6		0xb6
+#define AB3100_OTP7		0xb7
+#define AB3100_OTPP		0xbf
+
+static int __init ab3100_otp_read(struct ab3100_otp *otp)
+{
+	struct ab3100 *ab = otp->ab3100;
+	u8 otpval[8];
+	u8 otpp;
+	int err;
+
+	err = ab3100_get_register_interruptible(ab, AB3100_OTPP, &otpp);
+	if (err) {
+		dev_err(otp->dev, "unable to read OTPP register\n");
+		return err;
+	}
+
+	err = ab3100_get_register_page_interruptible(ab, AB3100_OTP0,
+						     otpval, 8);
+	if (err) {
+		dev_err(otp->dev, "unable to read OTP register page\n");
+		return err;
+	}
+
+	/* Cache OTP properties, they never change by nature */
+	otp->locked = (otpp & 0x80);
+	otp->freq = (otpp & 0x40) ? 32768 : 34100;
+	otp->paf = (otpval[1] & 0x80);
+	otp->imeich = (otpval[1] & 0x40);
+	otp->cid = ((otpval[1] << 8) | otpval[0]) & 0x3fff;
+	otp->tac = ((otpval[4] & 0x0f) << 16) | (otpval[3] << 8) | otpval[2];
+	otp->fac = ((otpval[5] & 0x0f) << 4) | (otpval[4] >> 4);
+	otp->svn = (otpval[7] << 12) | (otpval[6] << 4) | (otpval[5] >> 4);
+	return 0;
+}
+
+/*
+ * This is a simple debugfs human-readable file that dumps out
+ * the contents of the OTP.
+ */
+#ifdef CONFIG_DEBUGFS
+static int show_otp(struct seq_file *s, void *v)
+{
+	struct ab3100_otp *otp = s->private;
+	int err;
+
+	seq_printf(s, "OTP is %s\n", otp->locked ? "LOCKED" : "UNLOCKED");
+	seq_printf(s, "OTP clock switch startup is %uHz\n", otp->freq);
+	seq_printf(s, "PAF is %s\n", otp->paf ? "SET" : "NOT SET");
+	seq_printf(s, "IMEI is %s\n", otp->imeich ?
+		   "CHANGEABLE" : "NOT CHANGEABLE");
+	seq_printf(s, "CID: 0x%04x (decimal: %d)\n", otp->cid, otp->cid);
+	seq_printf(s, "IMEI: %u-%u-%u\n", otp->tac, otp->fac, otp->svn);
+	return 0;
+}
+
+static int ab3100_otp_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, ab3100_otp_show, inode->i_private);
+}
+
+static const struct file_operations ab3100_otp_operations = {
+	.open		= ab3100_otp_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init ab3100_otp_init_debugfs(struct device *dev,
+					  struct ab3100_otp *otp)
+{
+	otp->debugfs = debugfs_create_file("ab3100_otp", S_IFREG | S_IRUGO,
+					   NULL, otp,
+					   &ab3100_otp_operations);
+	if (!otp->debugfs) {
+		dev_err(dev, "AB3100 debugfs OTP file registration failed!\n");
+		return err;
+	}
+}
+
+static void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
+{
+	debugfs_remove_file(otp->debugfs);
+}
+#else
+/* Compile this out if debugfs not selected */
+static inline int __init ab3100_otp_init_debugfs(struct device *dev,
+						 struct ab3100_otp *otp)
+{
+	return 0;
+}
+
+static inline void __exit ab3100_otp_exit_debugfs(struct ab3100_otp *otp)
+{
+}
+#endif
+
+#define SHOW_AB3100_ATTR(name) \
+static ssize_t ab3100_otp_##name##_show(struct device *dev, \
+			       struct device_attribute *attr, \
+			       char *buf) \
+{\
+	struct ab3100 *ab3100 = dev_get_drvdata(dev); \
+	return sprintf(buf, "%u\n", ab3100->otp->name); \
+}
+
+SHOW_AB3100_ATTR(locked)
+SHOW_AB3100_ATTR(freq)
+SHOW_AB3100_ATTR(paf)
+SHOW_AB3100_ATTR(imeich)
+SHOW_AB3100_ATTR(cid)
+SHOW_AB3100_ATTR(fac)
+SHOW_AB3100_ATTR(tac)
+SHOW_AB3100_ATTR(svn)
+
+static struct device_attribute ab3100_otp_attrs[] = {
+	__ATTR(locked, S_IRUGO, ab3100_otp_locked_show, NULL),
+	__ATTR(freq, S_IRUGO, ab3100_otp_freq_show, NULL),
+	__ATTR(paf, S_IRUGO, ab3100_otp_paf_show, NULL),
+	__ATTR(imeich, S_IRUGO, ab3100_otp_imeich_show, NULL),
+	__ATTR(cid, S_IRUGO, ab3100_otp_cid_show, NULL),
+	__ATTR(fac, S_IRUGO, ab3100_otp_fac_show, NULL),
+	__ATTR(tac, S_IRUGO, ab3100_otp_tac_show, NULL),
+	__ATTR(svn, S_IRUGO, ab3100_otp_svn_show, NULL),
+};
+
+int __init ab3100_otp_init(struct ab3100 *ab3100)
+{
+	struct ab3100_otp *otp;
+	int err = 0;
+	int i;
+
+	otp = kzalloc(sizeof(struct ab3100_otp), GFP_KERNEL);
+	if (!otp) {
+		dev_err(ab3100->dev, "could not allocate AB3100 OTP device\n");
+		return -ENOMEM;
+	}
+	otp->dev = ab3100->dev;
+	otp->ab3100 = ab3100;
+	ab3100->otp = otp;
+
+	err = ab3100_otp_read(otp);
+	if (err)
+		return err;
+
+	dev_info(otp->dev, "AB3100 OTP readout registered\n");
+
+	/* sysfs entries */
+	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++) {
+		err = device_create_file(otp->dev,
+					 &ab3100_otp_attrs[i]);
+		if (err)
+			goto out_no_sysfs;
+	}
+
+	/* debugfs entries */
+	err = ab3100_otp_init_debugfs(otp->dev, otp);
+	if (err)
+		goto out_no_debugfs;
+
+	return 0;
+
+out_no_sysfs:
+	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
+		device_remove_file(otp->dev,
+				   &ab3100_otp_attrs[i]);
+out_no_debugfs:
+	kfree(otp);
+	return err;
+}
+
+void __exit ab3100_otp_exit(struct ab3100 *ab3100)
+{
+	struct ab3100_otp *otp = ab3100->otp;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ab3100_otp_attrs); i++)
+		device_remove_file(otp->dev,
+				   &ab3100_otp_attrs[i]);
+	ab3100_otp_exit_debugfs(otp);
+	kfree(otp);
+}
diff --git a/drivers/mfd/ab3100-otp.h b/drivers/mfd/ab3100-otp.h
new file mode 100644
index 0000000..eebdab5
--- /dev/null
+++ b/drivers/mfd/ab3100-otp.h
@@ -0,0 +1,21 @@
+/*
+ * drivers/mfd/ab3100-otp.h
+ *
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * Driver to read out OTP from the AB3100 Mixed-signal circuit
+ * Author: Linus Walleij 
+ */
+#ifdef CONFIG_AB3100_OTP
+int __init ab3100_otp_init(struct ab3100 *ab3100);
+void __exit ab3100_otp_exit(struct ab3100 *ab3100);
+#else
+static inline int __init ab3100_otp_init(struct ab3100 *ab3100)
+{
+	return 0;
+}
+
+static inline void __exit ab3100_otp_exit(struct ab3100 *ab3100)
+{
+}
+#endif
diff --git a/include/linux/mfd/ab3100.h b/include/linux/mfd/ab3100.h
index 56343b8..fbe82db 100644
--- a/include/linux/mfd/ab3100.h
+++ b/include/linux/mfd/ab3100.h
@@ -57,6 +57,40 @@
 #define AB3100_STR_VBUS					(0x80)
 
 /**
+ * struct ab3100_otp
+ * @dev containing device
+ * @ab3100 a pointer to the parent ab3100 device struct
+ * @locked whether the OTP is locked, after locking, no more bits
+ *       can be changed but before locking it is still possible
+ *       to change bits from 1->0.
+ * @freq clocking frequency for the OTP, this frequency is either
+ *       32768Hz or 1MHz/30
+ * @paf product activation flag, indicates whether this is a real
+ *       product (paf true) or a lab board etc (paf false)
+ * @imeich if this is set it is possible to override the
+ *       IMEI number found in the tac, fac and svn fields with
+ *       (secured) software
+ * @cid customer ID
+ * @tac type allocation code of the IMEI
+ * @fac final assembly code of the IMEI
+ * @svn software version number of the IMEI
+ * @debugfs a debugfs file used when dumping to file
+ */
+struct ab3100_otp {
+	struct device *dev;
+	struct ab3100 *ab3100;
+	bool locked;
+	u32 freq;
+	bool paf;
+	bool imeich;
+	u16 cid:14;
+	u32 tac:20;
+	u8 fac;
+	u32 svn:20;
+	struct dentry *debugfs;
+};
+
+/**
  * struct ab3100
  * @access_mutex: lock out concurrent accesses to the AB3100 registers
  * @dev: pointer to the containing device
@@ -68,6 +102,7 @@
  * @event_subscribers: event subscribers are listed here
  * @startup_events: a copy of the first reading of the event registers
  * @startup_events_read: whether the first events have been read
+ * @otp: pointer to the ab3100_otp substruct, if compiled in
  *
  * This struct is PRIVATE and devices using it should NOT
  * access ANY fields. It is used as a token for calling the
@@ -84,6 +119,7 @@ struct ab3100 {
 	struct blocking_notifier_head event_subscribers;
 	u32 startup_events;
 	bool startup_events_read;
+	struct ab3100_otp *otp;
 };
 
 int ab3100_set_register_interruptible(struct ab3100 *ab3100, u8 reg, u8
regval);
-- 
1.6.2.1
 
CD: 3ms