linux/drivers/mfd/wm831x-auxadc.c
Mark Brown 78bb3688ea mfd: Support multiple active WM831x AUXADC conversions
The WM831x AUXADC hardware can schedule multiple conversions at once,
allowing higher performance when more than one source is in use as we
can have the hardware start new conversions without having to wait for
a register write.

Take advantage of this in the interrupt driven case, maintaining a list of
callers that are waiting for AUXADC conversions and completing them all
simultaneously. The external interface of the AUXADC is not changed so
there will be limited use of the feature immediately.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2011-07-31 23:28:20 +02:00

300 lines
6.6 KiB
C

/*
* wm831x-auxadc.c -- AUXADC for Wolfson WM831x PMICs
*
* Copyright 2009-2011 Wolfson Microelectronics PLC.
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* 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.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/irq.h>
#include <linux/mfd/wm831x/auxadc.h>
#include <linux/mfd/wm831x/otp.h>
#include <linux/mfd/wm831x/regulator.h>
struct wm831x_auxadc_req {
struct list_head list;
enum wm831x_auxadc input;
int val;
struct completion done;
};
static int wm831x_auxadc_read_irq(struct wm831x *wm831x,
enum wm831x_auxadc input)
{
struct wm831x_auxadc_req *req;
int ret;
bool ena = false;
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
return -ENOMEM;
init_completion(&req->done);
req->input = input;
req->val = -ETIMEDOUT;
mutex_lock(&wm831x->auxadc_lock);
/* Enqueue the request */
list_add(&req->list, &wm831x->auxadc_pending);
ena = !wm831x->auxadc_active;
if (ena) {
ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
WM831X_AUX_ENA, WM831X_AUX_ENA);
if (ret != 0) {
dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n",
ret);
goto out;
}
}
/* Enable the conversion if not already running */
if (!(wm831x->auxadc_active & (1 << input))) {
ret = wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
1 << input, 1 << input);
if (ret != 0) {
dev_err(wm831x->dev,
"Failed to set AUXADC source: %d\n", ret);
goto out;
}
wm831x->auxadc_active |= 1 << input;
}
/* We convert at the fastest rate possible */
if (ena) {
ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
WM831X_AUX_CVT_ENA |
WM831X_AUX_RATE_MASK,
WM831X_AUX_CVT_ENA |
WM831X_AUX_RATE_MASK);
if (ret != 0) {
dev_err(wm831x->dev, "Failed to start AUXADC: %d\n",
ret);
goto out;
}
}
mutex_unlock(&wm831x->auxadc_lock);
/* Wait for an interrupt */
wait_for_completion_timeout(&req->done, msecs_to_jiffies(500));
mutex_lock(&wm831x->auxadc_lock);
list_del(&req->list);
ret = req->val;
out:
mutex_unlock(&wm831x->auxadc_lock);
kfree(req);
return ret;
}
static irqreturn_t wm831x_auxadc_irq(int irq, void *irq_data)
{
struct wm831x *wm831x = irq_data;
struct wm831x_auxadc_req *req;
int ret, input, val;
ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
if (ret < 0) {
dev_err(wm831x->dev,
"Failed to read AUXADC data: %d\n", ret);
return IRQ_NONE;
}
input = ((ret & WM831X_AUX_DATA_SRC_MASK)
>> WM831X_AUX_DATA_SRC_SHIFT) - 1;
if (input == 14)
input = WM831X_AUX_CAL;
val = ret & WM831X_AUX_DATA_MASK;
mutex_lock(&wm831x->auxadc_lock);
/* Disable this conversion, we're about to complete all users */
wm831x_set_bits(wm831x, WM831X_AUXADC_SOURCE,
1 << input, 0);
wm831x->auxadc_active &= ~(1 << input);
/* Turn off the entire convertor if idle */
if (!wm831x->auxadc_active)
wm831x_reg_write(wm831x, WM831X_AUXADC_CONTROL, 0);
/* Wake up any threads waiting for this request */
list_for_each_entry(req, &wm831x->auxadc_pending, list) {
if (req->input == input) {
req->val = val;
complete(&req->done);
}
}
mutex_unlock(&wm831x->auxadc_lock);
return IRQ_HANDLED;
}
static int wm831x_auxadc_read_polled(struct wm831x *wm831x,
enum wm831x_auxadc input)
{
int ret, src, timeout;
mutex_lock(&wm831x->auxadc_lock);
ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
WM831X_AUX_ENA, WM831X_AUX_ENA);
if (ret < 0) {
dev_err(wm831x->dev, "Failed to enable AUXADC: %d\n", ret);
goto out;
}
/* We force a single source at present */
src = input;
ret = wm831x_reg_write(wm831x, WM831X_AUXADC_SOURCE,
1 << src);
if (ret < 0) {
dev_err(wm831x->dev, "Failed to set AUXADC source: %d\n", ret);
goto out;
}
ret = wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL,
WM831X_AUX_CVT_ENA, WM831X_AUX_CVT_ENA);
if (ret < 0) {
dev_err(wm831x->dev, "Failed to start AUXADC: %d\n", ret);
goto disable;
}
/* If we're not using interrupts then poll the
* interrupt status register */
timeout = 5;
while (timeout) {
msleep(1);
ret = wm831x_reg_read(wm831x,
WM831X_INTERRUPT_STATUS_1);
if (ret < 0) {
dev_err(wm831x->dev,
"ISR 1 read failed: %d\n", ret);
goto disable;
}
/* Did it complete? */
if (ret & WM831X_AUXADC_DATA_EINT) {
wm831x_reg_write(wm831x,
WM831X_INTERRUPT_STATUS_1,
WM831X_AUXADC_DATA_EINT);
break;
} else {
dev_err(wm831x->dev,
"AUXADC conversion timeout\n");
ret = -EBUSY;
goto disable;
}
}
ret = wm831x_reg_read(wm831x, WM831X_AUXADC_DATA);
if (ret < 0) {
dev_err(wm831x->dev,
"Failed to read AUXADC data: %d\n", ret);
goto disable;
}
src = ((ret & WM831X_AUX_DATA_SRC_MASK)
>> WM831X_AUX_DATA_SRC_SHIFT) - 1;
if (src == 14)
src = WM831X_AUX_CAL;
if (src != input) {
dev_err(wm831x->dev, "Data from source %d not %d\n",
src, input);
ret = -EINVAL;
} else {
ret &= WM831X_AUX_DATA_MASK;
}
disable:
wm831x_set_bits(wm831x, WM831X_AUXADC_CONTROL, WM831X_AUX_ENA, 0);
out:
mutex_unlock(&wm831x->auxadc_lock);
return ret;
}
/**
* wm831x_auxadc_read: Read a value from the WM831x AUXADC
*
* @wm831x: Device to read from.
* @input: AUXADC input to read.
*/
int wm831x_auxadc_read(struct wm831x *wm831x, enum wm831x_auxadc input)
{
return wm831x->auxadc_read(wm831x, input);
}
EXPORT_SYMBOL_GPL(wm831x_auxadc_read);
/**
* wm831x_auxadc_read_uv: Read a voltage from the WM831x AUXADC
*
* @wm831x: Device to read from.
* @input: AUXADC input to read.
*/
int wm831x_auxadc_read_uv(struct wm831x *wm831x, enum wm831x_auxadc input)
{
int ret;
ret = wm831x_auxadc_read(wm831x, input);
if (ret < 0)
return ret;
ret *= 1465;
return ret;
}
EXPORT_SYMBOL_GPL(wm831x_auxadc_read_uv);
void wm831x_auxadc_init(struct wm831x *wm831x)
{
int ret;
mutex_init(&wm831x->auxadc_lock);
INIT_LIST_HEAD(&wm831x->auxadc_pending);
if (wm831x->irq && wm831x->irq_base) {
wm831x->auxadc_read = wm831x_auxadc_read_irq;
ret = request_threaded_irq(wm831x->irq_base +
WM831X_IRQ_AUXADC_DATA,
NULL, wm831x_auxadc_irq, 0,
"auxadc", wm831x);
if (ret < 0) {
dev_err(wm831x->dev, "AUXADC IRQ request failed: %d\n",
ret);
wm831x->auxadc_read = NULL;
}
}
if (!wm831x->auxadc_read)
wm831x->auxadc_read = wm831x_auxadc_read_polled;
}