qpnp-power-on: Print system timestamp on Power key event

Print system timestamp on Power key press and release events.
This would make debugging easy

Ported from: https://gerrit.mot.com/#/c/1320467/

Change-Id: I2c810e4b59c2d3bd8a705d407a339d9efe6fad3d
Reviewed-on: https://gerrit.mot.com/1320467
SLTApproved: Slta Waiver
SME-Granted: SME Approvals Granted
Tested-by: Jira Key
Reviewed-by: Ryan Lattrel <ryanl@motorola.com>
Reviewed-by: Ling Jin <lingjin@motorola.com>
Submit-Approved: Jira Key
Reviewed-on: https://gerrit.mot.com/1456668
Reviewed-on: https://gerrit.mot.com/1509721
Reviewed-by: Wang Wang <wangwang1@lenovo.com>

drivers/input/misc/qpnp-power-on.c

@@ -25,6 +25,7 @@
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/of_regulator.h>
+#include <linux/time.h>
 
 #define PMIC_VER_8941				0x01
 #define PMIC_VERSION_REG			0x0105
@@ -963,6 +964,9 @@ static int qpnp_pon_input_dispatch(struct qpnp_pon *pon, u32 pon_type)
 	uint pon_rt_sts;
 	u64 elapsed_us;
 	int rc;
+	struct timeval timestamp;
+	struct tm tm;
+	char buff[255];
 
 	cfg = qpnp_get_cfg(pon, pon_type);
 	if (!cfg)
@@ -989,6 +993,17 @@ static int qpnp_pon_input_dispatch(struct qpnp_pon *pon, u32 pon_type)
 	switch (cfg->pon_type) {
 	case PON_KPDPWR:
 		pon_rt_bit = QPNP_PON_KPDPWR_N_SET;
+
+		/* get the time stamp in readable format to print*/
+		do_gettimeofday(&timestamp);
+		time_to_tm((time_t)(timestamp.tv_sec), 0, &tm);
+		snprintf(buff, sizeof(buff),
+			"%u-%02d-%02d %02d:%02d:%02d UTC",
+			(int) tm.tm_year + 1900, tm.tm_mon + 1,
+			tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
+
+		pr_info("Report pwrkey %s event at: %s\n", pon_rt_bit &
+			pon_rt_sts ? "press" : "release", buff);
 		break;
 	case PON_RESIN:
 		pon_rt_bit = QPNP_PON_RESIN_N_SET;