Date:	Thu, 27 Aug 2009 19:35:00 +0200
From:	Samuel Ortiz <sameo@...ux.intel.com>
To:	Linus Walleij <linus.walleij@...ricsson.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] MFD AB3100 OTP readout v3

Hi Linus,

On Wed, Aug 19, 2009 at 11:09:28AM +0200, Linus Walleij wrote:
> 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 <linus.walleij@...ricsson.com>
> Reviewed-by: Samuel Ortiz <sameo@...ux.intel.com>
> ---
> 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 :-)
:-) It's your code after all, and you'll be the one having to add an OTP
platform device for _all_ platforms running an AB3100 ;)
So, I applied v2 to my for-next branch, thanks.


> ---
>  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 <linux/seq_file.h>
>  #include <linux/uaccess.h>
>  #include <linux/mfd/ab3100.h>
> +#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 <linus.walleij@...ricsson.com>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/mfd/ab3100.h>
> +#include <linux/debugfs.h>
> +#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 <linus.walleij@...ricsson.com>
> + */
> +#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
> 

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