I2C: TWL4030: Introduce twl4030 madc driver

Introduce twl4030 madc driver.
Signed-off-by: Mikko Ylinen <mikko.k.ylinen@nokia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

drivers/i2c/chips/twl4030-madc.c

+/*
+ * drivers/i2c/chips/twl4030-madc.c
+ *
+ * TWL4030 MADC module driver
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Mikko Ylinen <mikko.k.ylinen@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/i2c/twl4030.h>
+#include <linux/i2c/twl4030-madc.h>
+
+#include <asm/uaccess.h>
+
+#define TWL4030_MADC_PFX	"twl4030-madc: "
+
+static struct twl4030_madc_data {
+	struct mutex		lock;
+	struct work_struct	ws;
+	struct twl4030_madc_request	requests[TWL4030_MADC_NUM_METHODS];
+} twl4030_madc;
+
+static const char irq_pin = 1; /* XXX Read from platfrom data */
+
+static
+const struct twl4030_madc_conversion_method twl4030_conversion_methods[] = {
+	[TWL4030_MADC_RT] = {
+		.sel	= TWL4030_MADC_RTSELECT_LSB,
+		.avg	= TWL4030_MADC_RTAVERAGE_LSB,
+		.rbase	= TWL4030_MADC_RTCH0_LSB,
+	},
+	[TWL4030_MADC_SW1] = {
+		.sel	= TWL4030_MADC_SW1SELECT_LSB,
+		.avg	= TWL4030_MADC_SW1AVERAGE_LSB,
+		.rbase	= TWL4030_MADC_GPCH0_LSB,
+		.ctrl	= TWL4030_MADC_CTRL_SW1,
+	},
+	[TWL4030_MADC_SW2] = {
+		.sel	= TWL4030_MADC_SW2SELECT_LSB,
+		.avg	= TWL4030_MADC_SW2AVERAGE_LSB,
+		.rbase	= TWL4030_MADC_GPCH0_LSB,
+		.ctrl	= TWL4030_MADC_CTRL_SW2,
+	},
+};
+
+static void twl4030_madc_read(u8 reg, u8 *val)
+{
+	int ret = twl4030_i2c_read_u8(TWL4030_MODULE_MADC, val, reg);
+	if (ret)
+		printk(KERN_ERR TWL4030_MADC_PFX
+		       "unable to read register 0x%X\n", reg);
+}
+
+static void twl4030_madc_write(u8 reg, u8 val)
+{
+	int ret = twl4030_i2c_write_u8(TWL4030_MODULE_MADC, val, reg);
+	if (ret)
+		printk(KERN_ERR TWL4030_MADC_PFX
+		       "unable to write register 0x%X\n", reg);
+}
+
+static int twl4030_madc_channel_raw_read(u8 reg)
+{
+	u8 msb, lsb;
+
+	/* For each ADC channel, we have MSB and LSB register pair. MSB address
+	 * is always LSB address+1. reg parameter is the addr of LSB register */
+	twl4030_madc_read(reg+1, &msb);
+	twl4030_madc_read(reg, &lsb);
+
+	return (int)(((msb << 8) | lsb) >> 6);
+}
+
+static int twl4030_madc_read_channels(u8 reg_base, u16 channels, int *buf)
+{
+	int count = 0;
+	u8 reg, i;
+
+	if (unlikely(!buf))
+		return 0;
+
+	for (i = 0; i < TWL4030_MADC_MAX_CHANNELS; i++) {
+		if (channels & (1<<i)) {
+			reg = reg_base + 2*i;
+			buf[i] = twl4030_madc_channel_raw_read(reg);
+			count++;
+		}
+	}
+	return count;
+}
+
+static void twl4030_madc_enable_irq(int id)
+{
+	u8 val;
+
+	static u8 imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
+
+	twl4030_madc_read(imr, &val);
+	val &= ~(1 << id);
+	twl4030_madc_write(imr, val);
+}
+
+static void twl4030_madc_disable_irq(int id)
+{
+	u8 val;
+
+	static u8 imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
+
+	twl4030_madc_read(imr, &val);
+	val |= (1 << id);
+	twl4030_madc_write(imr, val);
+}
+
+static irqreturn_t twl4030_madc_irq_handler(int irq, void *madc_dev)
+{
+	u8 isr_val, imr_val;
+	static u8 isr, imr;
+	int i;
+
+	imr = (irq_pin == 1) ? TWL4030_MADC_IMR1 : TWL4030_MADC_IMR2;
+	isr = (irq_pin == 1) ? TWL4030_MADC_ISR1 : TWL4030_MADC_ISR2;
+
+	/* Use COR to ack interrupts since we have no shared IRQs in ISRx */
+	twl4030_madc_read(isr, &isr_val);
+	twl4030_madc_read(imr, &imr_val);
+
+	isr_val &= ~imr_val;
+
+	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
+
+		if (!(isr_val & (1<<i)))
+			continue;
+
+		twl4030_madc_disable_irq(i);
+		twl4030_madc.requests[i].result_pending = 1;
+	}
+
+	schedule_work(&twl4030_madc.ws);
+
+	return IRQ_HANDLED;
+}
+
+static void twl4030_madc_work(struct work_struct *ws)
+{
+	const struct twl4030_madc_conversion_method *method;
+	struct twl4030_madc_request *r;
+	int len, i;
+
+	mutex_lock(&twl4030_madc.lock);
+
+	for (i = 0; i < TWL4030_MADC_NUM_METHODS; i++) {
+
+		r = &twl4030_madc.requests[i];
+
+		/* No pending results for this method, move to next one */
+		if (!r->result_pending)
+			continue;
+
+		method = &twl4030_conversion_methods[r->method];
+
+		/* Read results */
+		len = twl4030_madc_read_channels(method->rbase,
+						 r->channels, r->rbuf);
+
+		/* Return results to caller */
+		if (r->func_cb != NULL) {
+			r->func_cb(len, r->channels, r->rbuf);
+			r->func_cb = NULL;
+		}
+
+		/* Free request */
+		r->result_pending = 0;
+		r->active	  = 0;
+	}
+
+	mutex_unlock(&twl4030_madc.lock);
+}
+
+static int twl4030_madc_set_irq(struct twl4030_madc_request *req)
+{
+	struct twl4030_madc_request *p;
+
+	p = &twl4030_madc.requests[req->method];
+
+	memcpy(p, req, sizeof *req);
+
+	twl4030_madc_enable_irq(req->method);
+
+	return 0;
+}
+
+static inline void twl4030_madc_start_conversion(int conv_method)
+{
+	const struct twl4030_madc_conversion_method *method;
+
+	method = &twl4030_conversion_methods[conv_method];
+
+	switch (conv_method) {
+	case TWL4030_MADC_SW1:
+	case TWL4030_MADC_SW2:
+		twl4030_madc_write(method->ctrl, TWL4030_MADC_SW_START);
+		break;
+	case TWL4030_MADC_RT:
+	default:
+		break;
+	}
+}
+
+static void twl4030_madc_wait_conversion_ready_ms(u8 *time, u8 status_reg)
+{
+	u8 reg = 0;
+
+	do {
+		msleep(1);
+		(*time)--;
+		twl4030_madc_read(status_reg, &reg);
+	} while (((reg & TWL4030_MADC_BUSY) && !(reg & TWL4030_MADC_EOC_SW)) &&
+		  (*time != 0));
+}
+
+int twl4030_madc_conversion(struct twl4030_madc_request *req)
+{
+	const struct twl4030_madc_conversion_method *method;
+	u8 wait_time, ch_msb, ch_lsb;
+	int ret;
+
+	if (unlikely(!req))
+		return -EINVAL;
+
+	/* Do we have a conversion request ongoing */
+	if (twl4030_madc.requests[req->method].active)
+		return -EBUSY;
+
+	ch_msb = (req->channels >> 8) & 0xff;
+	ch_lsb = req->channels & 0xff;
+
+	method = &twl4030_conversion_methods[req->method];
+
+	mutex_lock(&twl4030_madc.lock);
+
+	/* Select channels to be converted */
+	twl4030_madc_write(method->sel + 1, ch_msb);
+	twl4030_madc_write(method->sel, ch_lsb);
+
+	/* Select averaging for all channels if do_avg is set */
+	if (req->do_avg) {
+		twl4030_madc_write(method->avg + 1, ch_msb);
+		twl4030_madc_write(method->avg, ch_lsb);
+	}
+
+	if ((req->type == TWL4030_MADC_IRQ_ONESHOT) && (req->func_cb != NULL)) {
+		twl4030_madc_set_irq(req);
+		twl4030_madc_start_conversion(req->method);
+		twl4030_madc.requests[req->method].active = 1;
+		ret = 0;
+		goto out;
+	}
+
+	/* With RT method we should not be here anymore */
+	if (req->method == TWL4030_MADC_RT) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	twl4030_madc_start_conversion(req->method);
+	twl4030_madc.requests[req->method].active = 1;
+
+	/* Wait until conversion is ready (ctrl register returns EOC) */
+	wait_time = 50;
+	twl4030_madc_wait_conversion_ready_ms(&wait_time, method->ctrl);
+	if (wait_time == 0) {
+		printk(KERN_ERR TWL4030_MADC_PFX "conversion timeout!\n");
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	ret = twl4030_madc_read_channels(method->rbase, req->channels,
+					 req->rbuf);
+
+	twl4030_madc.requests[req->method].active = 0;
+
+out:
+	mutex_unlock(&twl4030_madc.lock);
+
+	return ret;
+}
+
+EXPORT_SYMBOL(twl4030_madc_conversion);
+
+static int twl4030_madc_set_current_generator(int chan, int on)
+{
+	int ret;
+	u8 regval;
+
+	/* Current generator is only available for ADCIN0 and ADCIN1. NB:
+	 * ADCIN1 current generator only works when AC or VBUS is present */
+	if (chan > 1)
+		return EINVAL;
+
+	ret = twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
+				  &regval, TWL4030_BCI_BCICTL1);
+	if (on)
+		regval |= (chan) ? TWL4030_BCI_ITHEN : TWL4030_BCI_TYPEN;
+	else
+		regval &= (chan) ? ~TWL4030_BCI_ITHEN : ~TWL4030_BCI_TYPEN;
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
+				   regval, TWL4030_BCI_BCICTL1);
+
+	return ret;
+}
+
+static int twl4030_madc_set_power(int on)
+{
+	u8 regval;
+
+	twl4030_madc_read(TWL4030_MADC_CTRL1, &regval);
+	if (on)
+		regval |= TWL4030_MADC_MADCON;
+	else
+		regval &= ~TWL4030_MADC_MADCON;
+	twl4030_madc_write(TWL4030_MADC_CTRL1, regval);
+
+	return 0;
+}
+
+static int twl4030_madc_ioctl(struct inode *inode, struct file *filp,
+			      unsigned int cmd, unsigned long arg)
+{
+	struct twl4030_madc_user_parms par;
+	int val, ret;
+
+	ret = copy_from_user(&par, (void __user *) arg, sizeof(par));
+	if (ret) {
+		printk(KERN_ERR TWL4030_MADC_PFX "copy_from_user: %d\n", ret);
+		return -EACCES;
+	}
+
+	switch (cmd) {
+	case TWL4030_MADC_IOCX_ADC_RAW_READ: {
+		struct twl4030_madc_request req;
+		if (par.channel >= TWL4030_MADC_MAX_CHANNELS)
+			return -EINVAL;
+
+		req.channels = (1<<par.channel);
+		req.do_avg	= par.average;
+		req.method	= TWL4030_MADC_SW1;
+
+		val = twl4030_madc_conversion(&req);
+		if (val <= 0) {
+			par.status = -1;
+		} else {
+			par.status = 0;
+			par.result = (u16)req.rbuf[par.channel];
+		}
+		break;
+					     }
+	default:
+		return -EINVAL;
+	}
+
+	ret = copy_to_user((void __user *) arg, &par, sizeof(par));
+	if (ret) {
+		printk(KERN_ERR TWL4030_MADC_PFX "copy_to_user: %d\n", ret);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static struct file_operations twl4030_madc_fileops = {
+	.owner = THIS_MODULE,
+	.ioctl = twl4030_madc_ioctl
+};
+
+static struct miscdevice twl4030_madc_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "twl4030-adc",
+	.fops = &twl4030_madc_fileops
+};
+
+static int __init twl4030_madc_init(void)
+{
+	int ret;
+	u8 regval;
+
+	ret = misc_register(&twl4030_madc_device);
+	if (ret == -1) {
+		printk(KERN_ERR TWL4030_MADC_PFX "misc_register() failed!\n");
+		return ret;
+	}
+	twl4030_madc_set_power(1);
+	twl4030_madc_set_current_generator(0, 1);
+
+	ret = twl4030_i2c_read_u8(TWL4030_MODULE_MAIN_CHARGE,
+				  &regval, TWL4030_BCI_BCICTL1);
+
+	regval |= TWL4030_BCI_MESBAT;
+
+	ret = twl4030_i2c_write_u8(TWL4030_MODULE_MAIN_CHARGE,
+				   regval, TWL4030_BCI_BCICTL1);
+
+	ret = request_irq(TWL4030_MODIRQ_MADC, twl4030_madc_irq_handler,
+			  IRQF_DISABLED, "twl4030_madc", &twl4030_madc);
+	if (ret)
+		printk(KERN_ERR TWL4030_MADC_PFX "request_irq: %d\n", ret);
+
+	mutex_init(&twl4030_madc.lock);
+
+	INIT_WORK(&twl4030_madc.ws, twl4030_madc_work);
+
+	printk(KERN_INFO TWL4030_MADC_PFX "initialised\n");
+
+	return ret;
+}
+
+static void __exit twl4030_madc_exit(void)
+{
+	twl4030_madc_set_power(0);
+	twl4030_madc_set_current_generator(0, 0);
+	free_irq(TWL4030_MODIRQ_MADC, &twl4030_madc);
+	cancel_work_sync(&twl4030_madc.ws);
+	misc_deregister(&twl4030_madc_device);
+}
+
+module_init(twl4030_madc_init);
+module_exit(twl4030_madc_exit);
+
+MODULE_AUTHOR("Nokia Corporation");
+MODULE_DESCRIPTION("twl4030 ADC driver");
+MODULE_LICENSE("GPL");

include/linux/i2c/twl4030-madc.h

+/*
+ * include/linux/i2c/twl4030-madc.h
+ *
+ * TWL4030 MADC module driver header
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Mikko Ylinen <mikko.k.ylinen@nokia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#ifndef _TWL4030_MADC_H
+#define _TWL4030_MADC_H
+
+struct twl4030_madc_conversion_method {
+	u8 sel;
+	u8 avg;
+	u8 rbase;
+	u8 ctrl;
+};
+
+#define TWL4030_MADC_MAX_CHANNELS 16
+
+struct twl4030_madc_request {
+	u16 channels;
+	u16 do_avg;
+	u16 method;
+	u16 type;
+	int active;
+	int result_pending;
+	int rbuf[TWL4030_MADC_MAX_CHANNELS];
+	void (*func_cb)(int len, int channels, int *buf);
+};
+
+enum conversion_methods {
+	TWL4030_MADC_RT,
+	TWL4030_MADC_SW1,
+	TWL4030_MADC_SW2,
+	TWL4030_MADC_NUM_METHODS
+};
+
+enum sample_type {
+	TWL4030_MADC_WAIT,
+	TWL4030_MADC_IRQ_ONESHOT,
+	TWL4030_MADC_IRQ_REARM
+};
+
+#define TWL4030_MADC_CTRL1		0x00
+#define TWL4030_MADC_CTRL2		0x01
+
+#define TWL4030_MADC_RTSELECT_LSB	0x02
+#define TWL4030_MADC_SW1SELECT_LSB	0x06
+#define TWL4030_MADC_SW2SELECT_LSB	0x0A
+
+#define TWL4030_MADC_RTAVERAGE_LSB	0x04
+#define TWL4030_MADC_SW1AVERAGE_LSB	0x08
+#define TWL4030_MADC_SW2AVERAGE_LSB	0x0C
+
+#define TWL4030_MADC_CTRL_SW1		0x12
+#define TWL4030_MADC_CTRL_SW2		0x13
+
+#define TWL4030_MADC_RTCH0_LSB		0x17
+#define TWL4030_MADC_GPCH0_LSB		0x37
+
+#define TWL4030_MADC_ISR1		0x61
+#define TWL4030_MADC_IMR1		0x62
+#define TWL4030_MADC_ISR2		0x63
+#define TWL4030_MADC_IMR2		0x64
+#define TWL4030_MADC_SIR		0x65
+#define TWL4030_MADC_EDR		0x66
+#define TWL4030_MADC_SIH_CTRL		0x67
+
+#define TWL4030_MADC_MADCON		(1<<0)	/* MADC power on */
+#define TWL4030_MADC_BUSY		(1<<0)	/* MADC busy */
+#define TWL4030_MADC_EOC_SW		(1<<1)	/* MADC conversion completion */
+#define TWL4030_MADC_SW_START		(1<<5)  /* MADC SWx start conversion */
+
+#define	TWL4030_MADC_ADCIN0		(1<<0)
+#define	TWL4030_MADC_ADCIN1		(1<<1)
+#define	TWL4030_MADC_ADCIN2		(1<<2)
+#define	TWL4030_MADC_ADCIN3		(1<<3)
+#define	TWL4030_MADC_ADCIN4		(1<<4)
+#define	TWL4030_MADC_ADCIN5		(1<<5)
+#define	TWL4030_MADC_ADCIN6		(1<<6)
+#define	TWL4030_MADC_ADCIN7		(1<<7)
+#define	TWL4030_MADC_ADCIN8		(1<<8)
+#define	TWL4030_MADC_ADCIN9		(1<<9)
+#define	TWL4030_MADC_ADCIN10		(1<<10)
+#define	TWL4030_MADC_ADCIN11		(1<<11)
+#define	TWL4030_MADC_ADCIN12		(1<<12)
+#define	TWL4030_MADC_ADCIN13		(1<<13)
+#define	TWL4030_MADC_ADCIN14		(1<<14)
+#define	TWL4030_MADC_ADCIN15		(1<<15)
+
+/* Fixed channels */
+#define TWL4030_MADC_BTEMP		TWL4030_MADC_ADCIN1
+#define TWL4030_MADC_VBUS		TWL4030_MADC_ADCIN8
+#define TWL4030_MADC_VBKB		TWL4030_MADC_ADCIN9
+#define	TWL4030_MADC_ICHG		TWL4030_MADC_ADCIN10
+#define TWL4030_MADC_VCHG		TWL4030_MADC_ADCIN11
+#define	TWL4030_MADC_VBAT		TWL4030_MADC_ADCIN12
+
+/* BCI related - XXX To be moved elsewhere */
+#define TWL4030_BCI_BCICTL1		0x23
+#define	TWL4030_BCI_MESBAT		(1<<1)
+#define	TWL4030_BCI_TYPEN		(1<<4)
+#define	TWL4030_BCI_ITHEN		(1<<3)
+
+#define TWL4030_MADC_IOC_MAGIC '`'
+#define TWL4030_MADC_IOCX_ADC_RAW_READ		_IO(TWL4030_MADC_IOC_MAGIC, 0)
+
+struct twl4030_madc_user_parms {
+	int channel;
+	int average;
+	int status;
+	u16 result;
+};
+
+int twl4030_madc_conversion(struct twl4030_madc_request *conv);
+
+#endif