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475 lines
12 KiB
475 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Real Time Clock driver for Wolfson Microelectronics WM831x |
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* |
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* Copyright (C) 2009 Wolfson Microelectronics PLC. |
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* |
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* Author: Mark Brown <[email protected]> |
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* |
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*/ |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/time.h> |
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#include <linux/rtc.h> |
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#include <linux/slab.h> |
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#include <linux/bcd.h> |
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#include <linux/interrupt.h> |
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#include <linux/ioctl.h> |
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#include <linux/completion.h> |
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#include <linux/mfd/wm831x/core.h> |
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#include <linux/delay.h> |
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#include <linux/platform_device.h> |
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#include <linux/random.h> |
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/* |
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* R16416 (0x4020) - RTC Write Counter |
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*/ |
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#define WM831X_RTC_WR_CNT_MASK 0xFFFF /* RTC_WR_CNT - [15:0] */ |
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#define WM831X_RTC_WR_CNT_SHIFT 0 /* RTC_WR_CNT - [15:0] */ |
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#define WM831X_RTC_WR_CNT_WIDTH 16 /* RTC_WR_CNT - [15:0] */ |
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/* |
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* R16417 (0x4021) - RTC Time 1 |
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*/ |
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#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */ |
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#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */ |
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#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */ |
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/* |
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* R16418 (0x4022) - RTC Time 2 |
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*/ |
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#define WM831X_RTC_TIME_MASK 0xFFFF /* RTC_TIME - [15:0] */ |
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#define WM831X_RTC_TIME_SHIFT 0 /* RTC_TIME - [15:0] */ |
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#define WM831X_RTC_TIME_WIDTH 16 /* RTC_TIME - [15:0] */ |
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/* |
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* R16419 (0x4023) - RTC Alarm 1 |
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*/ |
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#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */ |
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#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */ |
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#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */ |
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/* |
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* R16420 (0x4024) - RTC Alarm 2 |
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*/ |
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#define WM831X_RTC_ALM_MASK 0xFFFF /* RTC_ALM - [15:0] */ |
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#define WM831X_RTC_ALM_SHIFT 0 /* RTC_ALM - [15:0] */ |
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#define WM831X_RTC_ALM_WIDTH 16 /* RTC_ALM - [15:0] */ |
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/* |
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* R16421 (0x4025) - RTC Control |
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*/ |
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#define WM831X_RTC_VALID 0x8000 /* RTC_VALID */ |
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#define WM831X_RTC_VALID_MASK 0x8000 /* RTC_VALID */ |
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#define WM831X_RTC_VALID_SHIFT 15 /* RTC_VALID */ |
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#define WM831X_RTC_VALID_WIDTH 1 /* RTC_VALID */ |
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#define WM831X_RTC_SYNC_BUSY 0x4000 /* RTC_SYNC_BUSY */ |
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#define WM831X_RTC_SYNC_BUSY_MASK 0x4000 /* RTC_SYNC_BUSY */ |
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#define WM831X_RTC_SYNC_BUSY_SHIFT 14 /* RTC_SYNC_BUSY */ |
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#define WM831X_RTC_SYNC_BUSY_WIDTH 1 /* RTC_SYNC_BUSY */ |
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#define WM831X_RTC_ALM_ENA 0x0400 /* RTC_ALM_ENA */ |
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#define WM831X_RTC_ALM_ENA_MASK 0x0400 /* RTC_ALM_ENA */ |
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#define WM831X_RTC_ALM_ENA_SHIFT 10 /* RTC_ALM_ENA */ |
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#define WM831X_RTC_ALM_ENA_WIDTH 1 /* RTC_ALM_ENA */ |
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#define WM831X_RTC_PINT_FREQ_MASK 0x0070 /* RTC_PINT_FREQ - [6:4] */ |
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#define WM831X_RTC_PINT_FREQ_SHIFT 4 /* RTC_PINT_FREQ - [6:4] */ |
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#define WM831X_RTC_PINT_FREQ_WIDTH 3 /* RTC_PINT_FREQ - [6:4] */ |
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/* |
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* R16422 (0x4026) - RTC Trim |
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*/ |
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#define WM831X_RTC_TRIM_MASK 0x03FF /* RTC_TRIM - [9:0] */ |
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#define WM831X_RTC_TRIM_SHIFT 0 /* RTC_TRIM - [9:0] */ |
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#define WM831X_RTC_TRIM_WIDTH 10 /* RTC_TRIM - [9:0] */ |
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#define WM831X_SET_TIME_RETRIES 5 |
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#define WM831X_GET_TIME_RETRIES 5 |
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struct wm831x_rtc { |
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struct wm831x *wm831x; |
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struct rtc_device *rtc; |
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unsigned int alarm_enabled:1; |
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}; |
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static void wm831x_rtc_add_randomness(struct wm831x *wm831x) |
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{ |
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int ret; |
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u16 reg; |
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/* |
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* The write counter contains a pseudo-random number which is |
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* regenerated every time we set the RTC so it should be a |
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* useful per-system source of entropy. |
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*/ |
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ret = wm831x_reg_read(wm831x, WM831X_RTC_WRITE_COUNTER); |
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if (ret >= 0) { |
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reg = ret; |
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add_device_randomness(®, sizeof(reg)); |
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} else { |
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dev_warn(wm831x->dev, "Failed to read RTC write counter: %d\n", |
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ret); |
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} |
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} |
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/* |
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* Read current time and date in RTC |
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*/ |
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static int wm831x_rtc_readtime(struct device *dev, struct rtc_time *tm) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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struct wm831x *wm831x = wm831x_rtc->wm831x; |
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u16 time1[2], time2[2]; |
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int ret; |
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int count = 0; |
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/* Has the RTC been programmed? */ |
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ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); |
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if (ret < 0) { |
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dev_err(dev, "Failed to read RTC control: %d\n", ret); |
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return ret; |
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} |
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if (!(ret & WM831X_RTC_VALID)) { |
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dev_dbg(dev, "RTC not yet configured\n"); |
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return -EINVAL; |
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} |
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/* Read twice to make sure we don't read a corrupt, partially |
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* incremented, value. |
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*/ |
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do { |
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ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1, |
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2, time1); |
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if (ret != 0) |
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continue; |
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ret = wm831x_bulk_read(wm831x, WM831X_RTC_TIME_1, |
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2, time2); |
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if (ret != 0) |
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continue; |
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if (memcmp(time1, time2, sizeof(time1)) == 0) { |
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u32 time = (time1[0] << 16) | time1[1]; |
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rtc_time64_to_tm(time, tm); |
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return 0; |
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} |
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} while (++count < WM831X_GET_TIME_RETRIES); |
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dev_err(dev, "Timed out reading current time\n"); |
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return -EIO; |
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} |
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/* |
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* Set current time and date in RTC |
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*/ |
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static int wm831x_rtc_settime(struct device *dev, struct rtc_time *tm) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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struct wm831x *wm831x = wm831x_rtc->wm831x; |
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struct rtc_time new_tm; |
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unsigned long time, new_time; |
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int ret; |
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int count = 0; |
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time = rtc_tm_to_time64(tm); |
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ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_1, |
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(time >> 16) & 0xffff); |
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if (ret < 0) { |
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dev_err(dev, "Failed to write TIME_1: %d\n", ret); |
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return ret; |
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} |
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ret = wm831x_reg_write(wm831x, WM831X_RTC_TIME_2, time & 0xffff); |
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if (ret < 0) { |
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dev_err(dev, "Failed to write TIME_2: %d\n", ret); |
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return ret; |
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} |
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/* Wait for the update to complete - should happen first time |
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* round but be conservative. |
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*/ |
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do { |
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msleep(1); |
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ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); |
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if (ret < 0) |
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ret = WM831X_RTC_SYNC_BUSY; |
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} while (!(ret & WM831X_RTC_SYNC_BUSY) && |
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++count < WM831X_SET_TIME_RETRIES); |
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if (ret & WM831X_RTC_SYNC_BUSY) { |
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dev_err(dev, "Timed out writing RTC update\n"); |
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return -EIO; |
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} |
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/* Check that the update was accepted; security features may |
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* have caused the update to be ignored. |
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*/ |
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ret = wm831x_rtc_readtime(dev, &new_tm); |
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if (ret < 0) |
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return ret; |
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new_time = rtc_tm_to_time64(&new_tm); |
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/* Allow a second of change in case of tick */ |
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if (new_time - time > 1) { |
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dev_err(dev, "RTC update not permitted by hardware\n"); |
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return -EPERM; |
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} |
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return 0; |
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} |
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/* |
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* Read alarm time and date in RTC |
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*/ |
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static int wm831x_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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int ret; |
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u16 data[2]; |
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u32 time; |
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ret = wm831x_bulk_read(wm831x_rtc->wm831x, WM831X_RTC_ALARM_1, |
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2, data); |
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if (ret != 0) { |
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dev_err(dev, "Failed to read alarm time: %d\n", ret); |
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return ret; |
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} |
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time = (data[0] << 16) | data[1]; |
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rtc_time64_to_tm(time, &alrm->time); |
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ret = wm831x_reg_read(wm831x_rtc->wm831x, WM831X_RTC_CONTROL); |
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if (ret < 0) { |
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dev_err(dev, "Failed to read RTC control: %d\n", ret); |
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return ret; |
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} |
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if (ret & WM831X_RTC_ALM_ENA) |
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alrm->enabled = 1; |
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else |
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alrm->enabled = 0; |
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return 0; |
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} |
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static int wm831x_rtc_stop_alarm(struct wm831x_rtc *wm831x_rtc) |
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{ |
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wm831x_rtc->alarm_enabled = 0; |
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return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, |
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WM831X_RTC_ALM_ENA, 0); |
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} |
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static int wm831x_rtc_start_alarm(struct wm831x_rtc *wm831x_rtc) |
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{ |
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wm831x_rtc->alarm_enabled = 1; |
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return wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, |
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WM831X_RTC_ALM_ENA, WM831X_RTC_ALM_ENA); |
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} |
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static int wm831x_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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struct wm831x *wm831x = wm831x_rtc->wm831x; |
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int ret; |
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unsigned long time; |
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time = rtc_tm_to_time64(&alrm->time); |
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ret = wm831x_rtc_stop_alarm(wm831x_rtc); |
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if (ret < 0) { |
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dev_err(dev, "Failed to stop alarm: %d\n", ret); |
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return ret; |
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} |
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ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_1, |
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(time >> 16) & 0xffff); |
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if (ret < 0) { |
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dev_err(dev, "Failed to write ALARM_1: %d\n", ret); |
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return ret; |
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} |
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ret = wm831x_reg_write(wm831x, WM831X_RTC_ALARM_2, time & 0xffff); |
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if (ret < 0) { |
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dev_err(dev, "Failed to write ALARM_2: %d\n", ret); |
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return ret; |
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} |
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if (alrm->enabled) { |
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ret = wm831x_rtc_start_alarm(wm831x_rtc); |
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if (ret < 0) { |
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dev_err(dev, "Failed to start alarm: %d\n", ret); |
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return ret; |
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} |
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} |
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return 0; |
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} |
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static int wm831x_rtc_alarm_irq_enable(struct device *dev, |
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unsigned int enabled) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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if (enabled) |
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return wm831x_rtc_start_alarm(wm831x_rtc); |
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else |
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return wm831x_rtc_stop_alarm(wm831x_rtc); |
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} |
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static irqreturn_t wm831x_alm_irq(int irq, void *data) |
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{ |
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struct wm831x_rtc *wm831x_rtc = data; |
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rtc_update_irq(wm831x_rtc->rtc, 1, RTC_IRQF | RTC_AF); |
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return IRQ_HANDLED; |
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} |
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static const struct rtc_class_ops wm831x_rtc_ops = { |
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.read_time = wm831x_rtc_readtime, |
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.set_time = wm831x_rtc_settime, |
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.read_alarm = wm831x_rtc_readalarm, |
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.set_alarm = wm831x_rtc_setalarm, |
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.alarm_irq_enable = wm831x_rtc_alarm_irq_enable, |
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}; |
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#ifdef CONFIG_PM |
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/* Turn off the alarm if it should not be a wake source. */ |
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static int wm831x_rtc_suspend(struct device *dev) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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int ret, enable; |
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if (wm831x_rtc->alarm_enabled && device_may_wakeup(dev)) |
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enable = WM831X_RTC_ALM_ENA; |
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else |
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enable = 0; |
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ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, |
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WM831X_RTC_ALM_ENA, enable); |
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if (ret != 0) |
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dev_err(dev, "Failed to update RTC alarm: %d\n", ret); |
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return 0; |
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} |
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/* Enable the alarm if it should be enabled (in case it was disabled to |
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* prevent use as a wake source). |
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*/ |
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static int wm831x_rtc_resume(struct device *dev) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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int ret; |
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if (wm831x_rtc->alarm_enabled) { |
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ret = wm831x_rtc_start_alarm(wm831x_rtc); |
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if (ret != 0) |
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dev_err(dev, "Failed to restart RTC alarm: %d\n", ret); |
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} |
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return 0; |
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} |
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/* Unconditionally disable the alarm */ |
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static int wm831x_rtc_freeze(struct device *dev) |
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{ |
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struct wm831x_rtc *wm831x_rtc = dev_get_drvdata(dev); |
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int ret; |
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ret = wm831x_set_bits(wm831x_rtc->wm831x, WM831X_RTC_CONTROL, |
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WM831X_RTC_ALM_ENA, 0); |
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if (ret != 0) |
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dev_err(dev, "Failed to stop RTC alarm: %d\n", ret); |
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return 0; |
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} |
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#else |
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#define wm831x_rtc_suspend NULL |
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#define wm831x_rtc_resume NULL |
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#define wm831x_rtc_freeze NULL |
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#endif |
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static int wm831x_rtc_probe(struct platform_device *pdev) |
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{ |
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struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent); |
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struct wm831x_rtc *wm831x_rtc; |
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int alm_irq = wm831x_irq(wm831x, platform_get_irq_byname(pdev, "ALM")); |
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int ret = 0; |
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wm831x_rtc = devm_kzalloc(&pdev->dev, sizeof(*wm831x_rtc), GFP_KERNEL); |
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if (wm831x_rtc == NULL) |
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return -ENOMEM; |
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platform_set_drvdata(pdev, wm831x_rtc); |
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wm831x_rtc->wm831x = wm831x; |
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ret = wm831x_reg_read(wm831x, WM831X_RTC_CONTROL); |
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if (ret < 0) { |
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dev_err(&pdev->dev, "Failed to read RTC control: %d\n", ret); |
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return ret; |
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} |
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if (ret & WM831X_RTC_ALM_ENA) |
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wm831x_rtc->alarm_enabled = 1; |
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device_init_wakeup(&pdev->dev, 1); |
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wm831x_rtc->rtc = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(wm831x_rtc->rtc)) |
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return PTR_ERR(wm831x_rtc->rtc); |
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wm831x_rtc->rtc->ops = &wm831x_rtc_ops; |
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wm831x_rtc->rtc->range_max = U32_MAX; |
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ret = devm_rtc_register_device(wm831x_rtc->rtc); |
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if (ret) |
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return ret; |
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ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL, |
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wm831x_alm_irq, |
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IRQF_TRIGGER_RISING | IRQF_ONESHOT, |
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"RTC alarm", |
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wm831x_rtc); |
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if (ret != 0) { |
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dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n", |
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alm_irq, ret); |
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} |
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wm831x_rtc_add_randomness(wm831x); |
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return 0; |
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} |
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static const struct dev_pm_ops wm831x_rtc_pm_ops = { |
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.suspend = wm831x_rtc_suspend, |
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.resume = wm831x_rtc_resume, |
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.freeze = wm831x_rtc_freeze, |
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.thaw = wm831x_rtc_resume, |
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.restore = wm831x_rtc_resume, |
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.poweroff = wm831x_rtc_suspend, |
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}; |
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static struct platform_driver wm831x_rtc_driver = { |
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.probe = wm831x_rtc_probe, |
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.driver = { |
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.name = "wm831x-rtc", |
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.pm = &wm831x_rtc_pm_ops, |
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}, |
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}; |
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module_platform_driver(wm831x_rtc_driver); |
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MODULE_AUTHOR("Mark Brown <[email protected]>"); |
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MODULE_DESCRIPTION("RTC driver for the WM831x series PMICs"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:wm831x-rtc");
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