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/*
* Real Time Clock driver for Wolfson Microelectronics WM831x
*
* Copyright (C) 2009 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/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/bcd.h>
#include <linux/interrupt.h>
#include <linux/ioctl.h>
#include <linux/completion.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/random.h>
/*
* R16416 (0x4020) - RTC Write Counter
*/
#define WM831X_RTC_WR_CNT_MASK 0xFFFF /* RTC_WR_CNT - [15:0] */
#define WM831X_RTC_WR_CNT_SHIFT 0 /* RTC_WR_CNT - [15:0] */
#define WM831X_RTC_WR_CNT_WIDTH 16 /* RTC_WR_CNT - [15:0] */
/*
* R16417 (0x4021) - RTC Time 1
*/
#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
/*
* R16418 (0x4022) - RTC Time 2
*/
#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */
#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */
/*
* R16419 (0x4023) - RTC Alarm 1
*/
#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
/*
* R16420 (0x4024) - RTC Alarm 2
*/
#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */
#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */
/*
* R16421 (0x4025) - RTC Control
*/
#define WM831X_RTC_VALID 0x8000 /* RTC_VALID */
#define WM831X_RTC_VALID_MASK 0x8000 /* RTC_VALID */
#define WM831X_RTC_VALID_SHIFT 15 /* RTC_VALID */
#define WM831X_RTC_VALID_WIDTH 1 /* RTC_VALID */
#define WM831X_RTC_SYNC_BUSY 0x4000 /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_MASK 0x4000 /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_SHIFT 14 /* RTC_SYNC_BUSY */
#define WM831X_RTC_SYNC_BUSY_WIDTH 1 /* RTC_SYNC_BUSY */
#define WM831X_RTC_ALM_ENA 0x0400 /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_MASK 0x0400 /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_SHIFT 10 /* RTC_ALM_ENA */
#define WM831X_RTC_ALM_ENA_WIDTH 1 /* RTC_ALM_ENA */
#define WM831X_RTC_PINT_FREQ_MASK 0x0070 /* RTC_PINT_FREQ - [6:4] */
#define WM831X_RTC_PINT_FREQ_SHIFT 4 /* RTC_PINT_FREQ - [6:4] */
#define WM831X_RTC_PINT_FREQ_WIDTH 3 /* RTC_PINT_FREQ - [6:4] */
/*
* R16422 (0x4026) - RTC Trim
*/
#define WM831X_RTC_TRIM_MASK 0x03FF /* RTC_TRIM - [9:0] */
#define WM831X_RTC_TRIM_SHIFT 0 /* RTC_TRIM - [9:0] */
#define WM831X_RTC_TRIM_WIDTH 10 /* RTC_TRIM - [9:0] */
#define WM831X_SET_TIME_RETRIES 5
#define WM831X_GET_TIME_RETRIES 5
struct wm831x_rtc {
struct wm831x *wm831x;
struct rtc_device *rtc;
unsigned int alarm_enabled:1;
};
static void wm831x_rtc_add_randomness(struct wm831x *wm831x)
{
int ret;
u16 reg;
/*
* The write counter contains a pseudo-random number which is
* regenerated every time we set the RTC so it should be a
* useful per-system source of entropy.
*/
ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER);
if (ret >= 0) {
reg = ret;
add_device_randomness(®, sizeof(reg));
} else {
dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n",
ret);
}
}
/*
* Read current time and date in RTC
*/
static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm)
{
struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
struct wm831x *wm831x = wm831x_rtc->wm831x;
u16 time1[2], time2[2];
int ret;
int count = 0;
/* Has the RTC been programmed? */
ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
if (ret < 0) {
dev_err(dev, "Failed to read RTC control: %d\n", ret);
return ret;
}
if (!(ret & WM831X_RTC_VALID)) {
dev_dbg(dev, "RTC not yet configured\n");
return -EINVAL;
}
/* Read twice to make sure we don't read a corrupt, partially
* incremented, value.
*/
do {
ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
2, time1);
if (ret != 0)
continue;
ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1,
2, time2);
if (ret != 0)
continue;
if (memcmp(time1, time2, sizeof(time1)) == 0) {
u32 time = (time1[0] << 16) | time1[1];
rtc_time_to_tm(time, tm);
return rtc_valid_tm(tm);
}
} while (++count < WM831X_GET_TIME_RETRIES);
dev_err(dev, "Timed out reading current time\n");
return -EIO;
}
/*
* Set current time and date in RTC
*/
static int wm831x_rtc_set_mmss(struct device *dev, unsigned long time)
{
struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
struct wm831x *wm831x = wm831x_rtc->wm831x;
struct rtc_time new_tm;
unsigned long new_time;
int ret;
int count = 0;
ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1,
(time >> 16) & 0xffff);
if (ret < 0) {
dev_err(dev, "Failed to write TIME_1: %d\n", ret);
return ret;
}
ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff);
if (ret < 0) {
dev_err(dev, "Failed to write TIME_2: %d\n", ret);
return ret;
}
/* Wait for the update to complete - should happen first time
* round but be conservative.
*/
do {
msleep(1);
ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL);
if (ret < 0)
ret = WM831X_RTC_SYNC_BUSY;
} while (!(ret & WM831X_RTC_SYNC_BUSY) &&
++count < WM831X_SET_TIME_RETRIES);
if (ret & WM831X_RTC_SYNC_BUSY) {
dev_err(dev, "Timed out writing RTC update\n");
return -EIO;
}
/* Check that the update was accepted; security features may
* have caused the update to be ignored.
*/
ret = wm831x_rtc_readtime(dev, &new_tm);
if (ret < 0)
return ret;
ret = rtc_tm_to_time(&new_tm, &new_time);
if (ret < 0) {
dev_err(dev, "Failed to convert time: %d\n", ret);
return ret;
}
/* Allow a second of change in case of tick */
if (new_time - time > 1) {
dev_err(dev, "RTC update not permitted by hardware\n");
return -EPERM;
}
return 0;
}
/*
* Read alarm time and date in RTC
*/
static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
int ret;
u16 data[2];
u32 time;
ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1,
2, data);
if (ret != 0) {
dev_err(dev, "Failed to read alarm time: %d\n", ret);
return ret;
}
time = (data[0] << 16) | data[1];
rtc_time_to_tm(time, &alrm->time);
ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL);
if (ret < 0) {
dev_err(dev, "Failed to read RTC control: %d\n", ret);
return ret;
}
if (ret & WM831X_RTC_ALM_ENA)
alrm->enabled = 1;
else
alrm->enabled = 0;
return 0;
}
static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc)
{
wm831x_rtc->alarm_enabled = 0;
return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
WM831X_RTC_ALM_ENA, 0);
}
static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc)
{
wm831x_rtc->alarm_enabled = 1;
return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL,
WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA);
}
static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev);
struct wm831x *wm831x = wm831x_rtc->wm831x;
int ret;
unsigned long time;
ret = rtc_tm_to_time(&alrm->time, &time);
if (ret < <
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