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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Keerthy <j-keerthy@ti.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>
Subject: [PATCH 4.7 28/69] rtc: ds1307: Fix relying on reset value for weekday
Date: Wed, 28 Sep 2016 11:05:10 +0200	[thread overview]
Message-ID: <20160928090446.275301075@linuxfoundation.org> (raw)
In-Reply-To: <20160928090445.054716307@linuxfoundation.org>

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Keerthy <j-keerthy@ti.com>

commit e29385fab0bf94017fac130ee32f5bb2daf74417 upstream.

The reset value of weekday is 0x1. This is wrong since
the reset values of the day/month/year make up to Jan 1 2001.
When computed weekday comes out to be Monday. On a scale
of 1-7(Sunday - Saturday) it should be 0x2. So we should not
be relying on the reset value.

Hence compute the wday using the current date/month/year values.
Check if reset wday is any different from the computed wday,
If different then set the wday which we computed using
date/month/year values.

Document Referred:
http://ww1.microchip.com/downloads/en/DeviceDoc/20002266F.pdf

Fixes: 1d1945d261a2af "drivers/rtc/rtc-ds1307.c: add alarm support for mcp7941x chips"
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/rtc/rtc-ds1307.c |   28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -602,6 +602,8 @@ static const struct rtc_class_ops ds13xx
  * Alarm support for mcp794xx devices.
  */
 
+#define MCP794XX_REG_WEEKDAY		0x3
+#define MCP794XX_REG_WEEKDAY_WDAY_MASK	0x7
 #define MCP794XX_REG_CONTROL		0x07
 #	define MCP794XX_BIT_ALM0_EN	0x10
 #	define MCP794XX_BIT_ALM1_EN	0x20
@@ -1231,13 +1233,16 @@ static int ds1307_probe(struct i2c_clien
 {
 	struct ds1307		*ds1307;
 	int			err = -ENODEV;
-	int			tmp;
+	int			tmp, wday;
 	struct chip_desc	*chip = &chips[id->driver_data];
 	struct i2c_adapter	*adapter = to_i2c_adapter(client->dev.parent);
 	bool			want_irq = false;
 	bool			ds1307_can_wakeup_device = false;
 	unsigned char		*buf;
 	struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct rtc_time		tm;
+	unsigned long		timestamp;
+
 	irq_handler_t	irq_handler = ds1307_irq;
 
 	static const int	bbsqi_bitpos[] = {
@@ -1526,6 +1531,27 @@ read_rtc:
 				bin2bcd(tmp));
 	}
 
+	/*
+	 * Some IPs have weekday reset value = 0x1 which might not correct
+	 * hence compute the wday using the current date/month/year values
+	 */
+	ds1307_get_time(&client->dev, &tm);
+	wday = tm.tm_wday;
+	timestamp = rtc_tm_to_time64(&tm);
+	rtc_time64_to_tm(timestamp, &tm);
+
+	/*
+	 * Check if reset wday is different from the computed wday
+	 * If different then set the wday which we computed using
+	 * timestamp
+	 */
+	if (wday != tm.tm_wday) {
+		wday = i2c_smbus_read_byte_data(client, MCP794XX_REG_WEEKDAY);
+		wday = wday & ~MCP794XX_REG_WEEKDAY_WDAY_MASK;
+		wday = wday | (tm.tm_wday + 1);
+		i2c_smbus_write_byte_data(client, MCP794XX_REG_WEEKDAY, wday);
+	}
+
 	if (want_irq) {
 		device_set_wakeup_capable(&client->dev, true);
 		set_bit(HAS_ALARM, &ds1307->flags);



  parent reply	other threads:[~2016-09-28  9:10 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20160928090645uscas1p25d8333ed85efe1cdd54dcaecedfc3b84@uscas1p2.samsung.com>
2016-09-28  9:04 ` [PATCH 4.7 00/69] 4.7.6-stable review Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 01/69] reiserfs: fix "new_insert_key may be used uninitialized ..." Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 02/69] crypto: arm64/aes-ctr - fix NULL dereference in tail processing Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 03/69] crypto: arm/aes-ctr " Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 04/69] crypto: skcipher - Fix blkcipher walk OOM crash Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 05/69] crypto: echainiv - Replace chaining with multiplication Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 06/69] ocfs2/dlm: fix race between convert and migration Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 07/69] ocfs2: fix start offset to ocfs2_zero_range_for_truncate() Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 08/69] Revert "ocfs2: bump up o2cb network protocol version" Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 09/69] autofs: use dentry flags to block walks during expire Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 10/69] Disable "maybe-uninitialized" warning globally Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 12/69] Makefile: Mute warning for __builtin_return_address(>0) for tracing only Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 13/69] xfs: prevent dropping ioend completions during buftarg wait Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 14/69] mm: fix the page_swap_info() BUG_ON check Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 15/69] fsnotify: add a way to stop queueing events on group shutdown Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 16/69] fanotify: fix list corruption in fanotify_get_response() Greg Kroah-Hartman
2016-09-28  9:04   ` [PATCH 4.7 17/69] mm: memcontrol: make per-cpu charge cache IRQ-safe for socket accounting Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 18/69] cgroup: duplicate cgroup reference when cloning sockets Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 19/69] fix fault_in_multipages_...() on architectures with no-op access_ok() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 20/69] KEYS: Fix skcipher IV clobbering Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 21/69] arm64: Call numa_store_cpu_info() earlier Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 22/69] configfs: Return -EFBIG from configfs_write_bin_file Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 24/69] mtd: maps: sa1100-flash: potential NULL dereference Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 25/69] mtd: pmcmsp-flash: Allocating too much in init_msp_flash() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 26/69] mtd: spi-nor: fix wrong "fully unlocked" test Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 27/69] reset: Return -ENOTSUPP when not configured Greg Kroah-Hartman
2016-09-28  9:05   ` Greg Kroah-Hartman [this message]
2016-09-28  9:05   ` [PATCH 4.7 29/69] power: reset: hisi-reboot: Unmap region obtained by of_iomap Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 30/69] mac80211: reject TSPEC TIDs (TSIDs) for aggregation Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 31/69] fix memory leaks in tracing_buffers_splice_read() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 32/69] tracing: Move mutex to protect against resetting of seq data Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 33/69] mm: delete unnecessary and unsafe init_tlb_ubc() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 34/69] can: flexcan: fix resume function Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 35/69] net: can: ifi: Configure transmitter delay Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 36/69] iwlwifi: mvm: update TX queue before making a copy of the skb Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 37/69] nl80211: validate number of probe response CSA counters Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 38/69] btrfs: ensure that file descriptor used with subvol ioctls is a dir Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 39/69] x86/efi: Only map RAM into EFI page tables if in mixed-mode Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 40/69] irqchip/mips-gic: Fix local interrupts Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 41/69] i2c-eg20t: fix race between i2c init and interrupt enable Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 42/69] i2c: mux: pca954x: retry updating the mux selection on failure Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 43/69] i2c: qup: skip qup_i2c_suspend if the device is already runtime suspended Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 44/69] MIPS: Fix pre-r6 emulation FPU initialisation Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 45/69] MIPS: SMP: Fix possibility of deadlock when bringing CPUs online Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 46/69] MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 47/69] MIPS: Remove compact branch policy Kconfig entries Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 48/69] MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...) Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 49/69] MIPS: Add a missing ".set pop" in an early commit Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 50/69] MIPS: paravirt: Fix undefined reference to smp_bootstrap Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 51/69] x86/mm/pat: Prevent hang during boot when mapping pages Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 52/69] libceph: add an ONSTACK initializer for oids Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 53/69] ceph: fix symbol versioning for ceph_monc_do_statfs Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 54/69] ceph: Correctly return NXIO errors from ceph_llseek Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 55/69] libceph: fix return value check in alloc_msg_with_page_vector() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 56/69] PM / hibernate: Restore processor state before using per-CPU variables Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 57/69] PM / hibernate: Fix rtree_next_node() to avoid walking off list ends Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 58/69] power_supply: tps65217-charger: fix missing platform_set_drvdata() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 59/69] power: supply: max17042_battery: fix model download bug Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 60/69] ixgbe: Force VLNCTRL.VFE to be set in all VMDq paths Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 61/69] ixgbe: Re-enable ability to toggle VLAN filtering Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 62/69] igb: fix adjusting PTP timestamps for Tx/Rx latency Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 63/69] soc/tegra: pmc: Dont probe PMC if early initialisation fails Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 64/69] qxl: check for kmap failures Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 65/69] hostfs: Freeing an ERR_PTR in hostfs_fill_sb_common() Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 66/69] kasan: avoid overflowing quarantine size on low memory systems Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 67/69] mm/kasan: dont reduce quarantine in atomic contexts Greg Kroah-Hartman
2016-09-28  9:05   ` [PATCH 4.7 68/69] iw_cxgb4: stop MPA_REPLY timer when disconnecting Greg Kroah-Hartman
2016-09-28 16:46   ` [PATCH 4.7 00/69] 4.7.6-stable review Shuah Khan
2016-09-29  9:00     ` Greg Kroah-Hartman
2016-09-28 22:44   ` Guenter Roeck
2016-09-29  9:00     ` Greg Kroah-Hartman
     [not found]   ` <57ec0654.4756c20a.c7ddf.48d1@mx.google.com>
     [not found]     ` <7ha8erru8h.fsf@baylibre.com>
2016-09-29  8:33       ` Greg Kroah-Hartman
2016-09-29 14:46         ` Kevin Hilman
2016-09-29 15:26           ` Greg Kroah-Hartman

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