n810: Add basic battery management driver

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@22760 3c298f89-4303-0410-b956-a3cf2f4a3e73

2 files changed, 490 insertions, 0 deletions

diff --git a/target/linux/omap24xx/config-2.6.35 b/target/linux/omap24xx/config-2.6.35
index b5ac7a5ad2..0294b4b72b 100644
--- a/target/linux/omap24xx/config-2.6.35
+++ b/target/linux/omap24xx/config-2.6.35
@@ -351,6 +351,7 @@ CONFIG_MTD_ONENAND_OTP=y
 # CONFIG_MTD_ONENAND_VERIFY_WRITE is not set
 # CONFIG_MTD_ROOTFS_ROOT_DEV is not set
 # CONFIG_MTD_ROOTFS_SPLIT is not set
+CONFIG_N810BM=y
 CONFIG_NAMESPACES=y
 CONFIG_NEED_DMA_MAP_STATE=y
 CONFIG_NETDEV_10000=y
diff --git a/target/linux/omap24xx/patches-2.6.35/900-n810-battery-management.patch b/target/linux/omap24xx/patches-2.6.35/900-n810-battery-management.patch
new file mode 100644
index 0000000000..fcb46c0e3b
--- /dev/null
+++ b/target/linux/omap24xx/patches-2.6.35/900-n810-battery-management.patch
@@ -0,0 +1,489 @@
+---
+ arch/arm/mach-omap2/board-n8x0.c |   13 +
+ drivers/cbus/Kconfig             |   12 +
+ drivers/cbus/Makefile            |    1 
+ drivers/cbus/n810bm.c            |  396 +++++++++++++++++++++++++++++++++++++++
+ drivers/cbus/retu.c              |    4 
+ drivers/cbus/retu.h              |    2 
+ 6 files changed, 425 insertions(+), 3 deletions(-)
+
+--- linux-2.6.35.3.orig/drivers/cbus/Kconfig
++++ linux-2.6.35.3/drivers/cbus/Kconfig
+@@ -94,4 +94,16 @@ config CBUS_RETU_HEADSET
+ 	  to Retu/Vilma. Detection state and events are exposed through
+ 	  sysfs.
+ 
++config N810BM
++	depends on CBUS_RETU && CBUS_TAHVO
++	tristate "Nokia n810 battery management"
++	---help---
++	  Nokia n810 device battery management.
++
++	  WARNING: This driver is based on reverse engineered information.
++	  It is possibly dangerous to use this software.
++	  Use this software at your own risk!
++
++	  If unsure, say N.
++
+ endmenu
+--- linux-2.6.35.3.orig/drivers/cbus/Makefile
++++ linux-2.6.35.3/drivers/cbus/Makefile
+@@ -12,3 +12,4 @@ obj-$(CONFIG_CBUS_RETU_WDT)	+= retu-wdt.
+ obj-$(CONFIG_CBUS_TAHVO_USER)	+= tahvo-user.o
+ obj-$(CONFIG_CBUS_RETU_USER)	+= retu-user.o
+ obj-$(CONFIG_CBUS_RETU_HEADSET)	+= retu-headset.o
++obj-$(CONFIG_N810BM)		+= n810bm.o
+--- /dev/null
++++ linux-2.6.35.3/drivers/cbus/n810bm.c
+@@ -0,0 +1,396 @@
++/*
++ *   Nokia n810 battery management
++ *
++ *   WARNING: This driver is based on reverse engineered information.
++ *            It is possibly dangerous to use this software.
++ *            Use this software at your own risk!
++ *
++ *   Copyright (c) 2010 Michael Buesch <mb@bu3sch.de>
++ *
++ *   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.
++ */
++
++#include <linux/module.h>
++#include <linux/device.h>
++#include <linux/platform_device.h>
++#include <linux/slab.h>
++#include <linux/spinlock.h>
++#include <linux/timer.h>
++#include <linux/reboot.h>
++
++#include "retu.h"
++#include "tahvo.h"
++
++
++#define N810BM_CHECK_INTERVAL		(HZ * 5)
++#define N810BM_MIN_VOLTAGE_THRES	3400 /* Absolute minimum voltage threshold */
++/* FIXME: Not sure about the actual value of the low threshold, yet.
++ * We must give userspace a chance to detect undervoltage and perform
++ * a clean shutdown, before we flip the big switch. */
++
++
++/* Battery related retu ADC channels */
++#define RETU_ADC_BSI		0x01 /* Battery Size Indicator */
++#define RETU_ADC_BATTVOLT	0x08 /* Battery voltage measurement */
++
++/* RETU_ADC_BSI
++ * The battery size indicator ADC measures the resistance between
++ * the battery BSI pin and ground. This is used to detect the battery
++ * capacity, as the BSI resistor is related to capacity.
++ *
++ * Manually measured lookup table.
++ * Hard to measure, thus not very accurate.
++ *
++ * Resistance  |  ADC value
++ * ========================
++ * 120k        |  0x3AC
++ * 110k        |  0x37C
++ * 100k        |  0x351
++ *  90k        |  0x329
++ */
++
++/* RETU_ADC_BATTVOLT
++ * Manually measured lookup table.
++ * Hard to measure, thus not very accurate.
++ *
++ * Voltage  |  ADC value
++ * =====================
++ * 2.80V    |  0x037
++ * 2.90V    |  0x05E
++ * 3.00V    |  0x090
++ * 3.10V    |  0x0A4
++ * 3.20V    |  0x0CC
++ * 3.30V    |  0x0EF
++ * 3.40V    |  0x115
++ * 3.50V    |  0x136
++ * 3.60V    |  0x15C
++ * 3.70V    |  0x187
++ * 3.80V    |  0x1A5
++ * 3.90V    |  0x1C9
++ * 4.00V    |  0x1ED
++ * 4.10V    |  0x212
++ * 4.20V    |  0x236
++ */
++
++
++enum n810bm_capacity {
++	N810BM_CAP_UNKNOWN	= 0,
++	N810BM_CAP_1500MAH	= 1500,	/* 1500 mAh battery */
++};
++
++struct n810bm {
++	struct platform_device *pdev;
++	enum n810bm_capacity capacity;
++	struct timer_list check_timer;
++	spinlock_t lock;
++};
++
++
++static NORET_TYPE void n810bm_emergency(struct n810bm *bm, const char *message) ATTRIB_NORET;
++static void n810bm_emergency(struct n810bm *bm, const char *message)
++{
++	printk(KERN_EMERG "Nokia n810 battery management fatal fault: %s\n", message);
++	/* Force a hard shutdown. */
++	machine_power_off();
++	panic("n810bm: Failed to halt machine in emergency state\n");
++}
++
++#if 0
++static u16 retu_read(struct n810bm *bm, unsigned int reg)
++{
++	int ret;
++	unsigned long flags;
++
++	spin_lock_irqsave(&retu_lock, flags);
++	ret = retu_read_reg(reg);
++	spin_unlock_irqrestore(&retu_lock, flags);
++	if (ret < 0 || ret > 0xFFFF)
++		n810bm_emergency(bm, "retu_read");
++
++	return ret;
++}
++#endif
++
++static void retu_maskset(struct n810bm *bm, unsigned int reg, u16 mask, u16 set)
++{
++	int ret;
++	unsigned long flags;
++	u16 value;
++
++	spin_lock_irqsave(&retu_lock, flags);
++	if (~mask) {
++		ret = retu_read_reg(reg);
++		if (ret < 0 || ret > 0xFFFF)
++			goto fatal_unlock;
++		value = ret;
++	} else
++		value = 0;
++	value &= ~mask;
++	value |= set;
++	ret = retu_write_reg(reg, value);
++	if (ret)
++		goto fatal_unlock;
++	spin_unlock_irqrestore(&retu_lock, flags);
++
++	return;
++
++fatal_unlock:
++	spin_unlock_irqrestore(&retu_lock, flags);
++	n810bm_emergency(bm, "retu_maskset");
++}
++
++static inline void retu_write(struct n810bm *bm, unsigned int reg, u16 value)
++{
++	return retu_maskset(bm, reg, 0xFFFF, value);
++}
++
++static int retu_adc_average(struct n810bm *bm, unsigned int chan,
++			    unsigned int nr_passes)
++{
++	unsigned int i, value = 0;
++	int ret;
++
++	if (WARN_ON(!nr_passes))
++		return 0;
++	for (i = 0; i < nr_passes; i++) {
++		ret = retu_read_adc(chan);
++		if (ret < 0)
++			return ret;
++		value += ret;
++	}
++	value /= nr_passes;
++
++	return value;
++}
++
++/* Measure the battery voltage. Returns the value in mV (or negative value on error). */
++static int n810bm_measure_batt_voltage(struct n810bm *bm)
++{
++	int adc;
++	unsigned int mv;
++	const unsigned int scale = 1000;
++
++	adc = retu_adc_average(bm, RETU_ADC_BATTVOLT, 5);
++	if (adc < 0)
++		return adc;
++	if (adc <= 0x37)
++		return 2800;
++	mv = 2800 + ((adc - 0x37) * (((4200 - 2800) * scale) / (0x236 - 0x37))) / scale;
++
++	return mv;
++}
++
++/* Read the battery capacity via BSI pin. */
++static enum n810bm_capacity n810bm_read_batt_capacity(struct n810bm *bm)
++{
++	int adc;
++	const unsigned int hyst = 16;
++
++	adc = retu_adc_average(bm, RETU_ADC_BSI, 5);
++	if (adc < 0)
++		return N810BM_CAP_UNKNOWN;
++
++	if (adc >= 0x3AC - hyst && adc <= 0x3AC + hyst)
++		return N810BM_CAP_1500MAH;
++
++	return N810BM_CAP_UNKNOWN;
++}
++
++struct mv2p {
++	unsigned int mv;
++	unsigned int p;
++};
++
++/* Convert a battery voltage (in mV) to percentage. */
++static unsigned int n810bm_mvolt2percent(unsigned int mv)
++{
++	/* FIXME: Create a correct table. */
++	static const struct mv2p table[] = {
++		{ .mv = 4200, .p = 100, },
++		{ .mv = 4150, .p = 90, },
++		{ .mv = 4100, .p = 80, },
++		{ .mv = 4050, .p = 70, },
++		{ .mv = 4000, .p = 60, },
++		{ .mv = 3950, .p = 50, },
++		{ .mv = 3900, .p = 40, },
++		{ .mv = 3850, .p = 30, },
++		{ .mv = 3800, .p = 20, },
++		{ .mv = 3750, .p = 10, },
++		{ .mv = 3700, .p = 0, },
++	};
++	const struct mv2p *e;
++	unsigned int i;
++
++	for (i = 0; i < ARRAY_SIZE(table); i++) {
++		e = &table[i];
++		if (mv >= e->mv)
++			return e->p;
++	}
++
++	return 0;
++}
++
++static void n810bm_check_timer(unsigned long data)
++{
++	struct n810bm *bm = (struct n810bm *)data;
++	unsigned long flags;
++	int mv;
++
++	spin_lock_irqsave(&bm->lock, flags);
++
++	mv = n810bm_measure_batt_voltage(bm);
++	if (mv < 0)
++		n810bm_emergency(bm, "check timer: Failed to measure");
++	if (mv < N810BM_MIN_VOLTAGE_THRES)
++		n810bm_emergency(bm, "check timer: Minimum voltage threshold reached");
++
++	mod_timer(&bm->check_timer, round_jiffies(jiffies + N810BM_CHECK_INTERVAL));
++	spin_unlock_irqrestore(&bm->lock, flags);
++
++	return;
++}
++
++static ssize_t n810bm_attr_charge_show(struct device *dev,
++				       struct device_attribute *attr,
++				       char *buf)
++{
++	struct platform_device *pdev = to_platform_device(dev);
++	struct n810bm *bm = platform_get_drvdata(pdev);
++	int err = -ENODEV;
++	ssize_t count = 0;
++	int millivolt;
++
++	spin_lock_irq(&bm->lock);
++	millivolt = n810bm_measure_batt_voltage(bm);
++	if (millivolt >= 0) {
++		count = snprintf(buf, PAGE_SIZE, "%u\n",
++				 n810bm_mvolt2percent(millivolt));
++		err = 0;
++	}
++	spin_unlock_irq(&bm->lock);
++
++	return err ? err : count;
++}
++static DEVICE_ATTR(batt_charge, 0444, n810bm_attr_charge_show, NULL);
++
++static ssize_t n810bm_attr_capacity_show(struct device *dev,
++					 struct device_attribute *attr,
++					 char *buf)
++{
++	struct platform_device *pdev = to_platform_device(dev);
++	struct n810bm *bm = platform_get_drvdata(pdev);
++	ssize_t count;
++
++	spin_lock_irq(&bm->lock);
++	count = snprintf(buf, PAGE_SIZE, "%u\n",
++			 (unsigned int)bm->capacity);
++	spin_unlock_irq(&bm->lock);
++
++	return count;
++}
++static DEVICE_ATTR(batt_capacity, 0444, n810bm_attr_capacity_show, NULL);
++
++static void n810bm_hw_exit(struct n810bm *bm)
++{
++	retu_write(bm, RETU_REG_ADCSCR, 0);
++}
++
++static int n810bm_hw_init(struct n810bm *bm)
++{
++	retu_write(bm, RETU_REG_ADCSCR, 0);
++
++	bm->capacity = n810bm_read_batt_capacity(bm);
++	if (bm->capacity == N810BM_CAP_UNKNOWN) {
++		dev_err(&bm->pdev->dev, "Unknown battery detected");
++		return -ENODEV;
++	}
++	dev_info(&bm->pdev->dev, "Detected %u mAh battery\n",
++		 (unsigned int)bm->capacity);
++
++	return 0;
++}
++
++static int __devinit n810bm_probe(struct platform_device *pdev)
++{
++	struct n810bm *bm;
++	int err;
++
++	bm = kzalloc(sizeof(*bm), GFP_KERNEL);
++	if (!bm)
++		return -ENOMEM;
++	bm->pdev = pdev;
++	platform_set_drvdata(pdev, bm);
++	spin_lock_init(&bm->lock);
++	setup_timer(&bm->check_timer, n810bm_check_timer, (unsigned long)bm);
++
++	err = n810bm_hw_init(bm);
++	if (err)
++		goto err_free;
++	err = device_create_file(&pdev->dev, &dev_attr_batt_charge);
++	if (err)
++		goto err_exit;
++	err = device_create_file(&pdev->dev, &dev_attr_batt_capacity);
++	if (err)
++		goto err_rem_charge;
++
++	mod_timer(&bm->check_timer, round_jiffies(jiffies + N810BM_CHECK_INTERVAL));
++
++	dev_info(&pdev->dev, "Battery management initialized");
++
++	return 0;
++
++err_rem_charge:
++	device_remove_file(&pdev->dev, &dev_attr_batt_charge);
++err_exit:
++	n810bm_hw_exit(bm);
++err_free:
++	kfree(bm);
++	platform_set_drvdata(pdev, NULL);
++	return err;
++}
++
++static int __devexit n810bm_remove(struct platform_device *pdev)
++{
++	struct n810bm *bm = platform_get_drvdata(pdev);
++
++	del_timer_sync(&bm->check_timer);
++	device_remove_file(&pdev->dev, &dev_attr_batt_capacity);
++	device_remove_file(&pdev->dev, &dev_attr_batt_charge);
++	n810bm_hw_exit(bm);
++
++	kfree(bm);
++	platform_set_drvdata(pdev, NULL);
++
++	return 0;
++}
++
++static struct platform_driver n810bm_driver = {
++	.remove		= __devexit_p(n810bm_remove),
++	.driver		= {
++		.name	= "n810bm",
++	}
++};
++
++static int __init n810bm_modinit(void)
++{
++	return platform_driver_probe(&n810bm_driver, n810bm_probe);
++}
++module_init(n810bm_modinit);
++
++static void __exit n810bm_modexit(void)
++{
++	platform_driver_unregister(&n810bm_driver);
++}
++module_exit(n810bm_modexit);
++
++MODULE_DESCRIPTION("Nokia n810 battery management");
++MODULE_LICENSE("GPL");
++MODULE_AUTHOR("Michael Buesch");
+--- linux-2.6.35.3.orig/drivers/cbus/retu.c
++++ linux-2.6.35.3/drivers/cbus/retu.c
+@@ -85,10 +85,10 @@ int retu_read_reg(int reg)
+  *
+  * This function writes a value to the specified register
+  */
+-void retu_write_reg(int reg, u16 val)
++int retu_write_reg(int reg, u16 val)
+ {
+ 	BUG_ON(!retu_initialized);
+-	cbus_write_reg(cbus_host, RETU_ID, reg, val);
++	return cbus_write_reg(cbus_host, RETU_ID, reg, val);
+ }
+ 
+ void retu_set_clear_reg_bits(int reg, u16 set, u16 clear)
+--- linux-2.6.35.3.orig/drivers/cbus/retu.h
++++ linux-2.6.35.3/drivers/cbus/retu.h
+@@ -58,7 +58,7 @@
+ #define	MAX_RETU_IRQ_HANDLERS	16
+ 
+ int retu_read_reg(int reg);
+-void retu_write_reg(int reg, u16 val);
++int retu_write_reg(int reg, u16 val);
+ void retu_set_clear_reg_bits(int reg, u16 set, u16 clear);
+ int retu_read_adc(int channel);
+ int retu_request_irq(int id, void *irq_handler, unsigned long arg, char *name);
+--- linux-2.6.35.3.orig/arch/arm/mach-omap2/board-n8x0.c
++++ linux-2.6.35.3/arch/arm/mach-omap2/board-n8x0.c
+@@ -875,6 +875,17 @@ extern void n8x0_blizzard_init(void);
+ #define n8x0_blizzard_init() 0
+ #endif
+ 
++static struct platform_device n810_bm_device = {
++	.name		= "n810bm",
++	.id		= -1,
++};
++
++static void __init n810_bm_init(void)
++{
++	if (platform_device_register(&n810_bm_device))
++		BUG();
++}
++
+ static void __init n8x0_init_machine(void)
+ {
+ 	platform_device_register(&n8x0_cbus_device);
+@@ -901,6 +912,8 @@ static void __init n8x0_init_machine(voi
+ 	n8x0_onenand_init();
+ 	n8x0_mmc_init();
+ 	n8x0_usb_init();
++
++	n810_bm_init();
+ }
+ 
+ MACHINE_START(NOKIA_N800, "Nokia N800")