From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: [bug report] twl4030_charger: use runtime_pm to keep usb phy active while charging. Date: Tue, 11 Oct 2016 14:30:25 +0300 Message-ID: <20161011113025.GA13807@mwanda> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:17150 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752378AbcJKLap (ORCPT ); Tue, 11 Oct 2016 07:30:45 -0400 Content-Disposition: inline Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: neil@brown.name Cc: linux-pm@vger.kernel.org Hello NeilBrown, The patch e57c4a67d712: "twl4030_charger: use runtime_pm to keep usb phy active while charging." from Jul 30, 2015, leads to the following static checker warning: drivers/power/supply/twl4030_charger.c:521 twl4030_charger_enable_usb() error: 'bci->transceiver' dereferencing possible ERR_PTR() drivers/power/supply/twl4030_charger.c 468 static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable) 469 { 470 int ret; 471 472 if (bci->usb_mode == CHARGE_OFF) 473 enable = false; 474 if (enable && !IS_ERR_OR_NULL(bci->transceiver)) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ We assume that ->transceiver can be NULL. 475 476 twl4030_charger_update_current(bci); 477 478 /* Need to keep phy powered */ 479 if (!bci->usb_enabled) { 480 pm_runtime_get_sync(bci->transceiver->dev); 481 bci->usb_enabled = 1; 482 } 483 484 if (bci->usb_mode == CHARGE_AUTO) 485 /* forcing the field BCIAUTOUSB (BOOT_BCI[1]) to 1 */ 486 ret = twl4030_clear_set_boot_bci(0, TWL4030_BCIAUTOUSB); 487 488 /* forcing USBFASTMCHG(BCIMFSTS4[2]) to 1 */ 489 ret = twl4030_clear_set(TWL_MODULE_MAIN_CHARGE, 0, 490 TWL4030_USBFASTMCHG, TWL4030_BCIMFSTS4); 491 if (bci->usb_mode == CHARGE_LINEAR) { 492 twl4030_clear_set_boot_bci(TWL4030_BCIAUTOAC|TWL4030_CVENAC, 0); 493 /* Watch dog key: WOVF acknowledge */ 494 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x33, 495 TWL4030_BCIWDKEY); 496 /* 0x24 + EKEY6: off mode */ 497 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a, 498 TWL4030_BCIMDKEY); 499 /* EKEY2: Linear charge: USB path */ 500 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x26, 501 TWL4030_BCIMDKEY); 502 /* WDKEY5: stop watchdog count */ 503 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf3, 504 TWL4030_BCIWDKEY); 505 /* enable MFEN3 access */ 506 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x9c, 507 TWL4030_BCIMFKEY); 508 /* ICHGEOCEN - end-of-charge monitor (current < 80mA) 509 * (charging continues) 510 * ICHGLOWEN - current level monitor (charge continues) 511 * don't monitor over-current or heat save 512 */ 513 ret = twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0xf0, 514 TWL4030_BCIMFEN3); 515 } 516 } else { 517 ret = twl4030_clear_set_boot_bci(TWL4030_BCIAUTOUSB, 0); 518 ret |= twl_i2c_write_u8(TWL_MODULE_MAIN_CHARGE, 0x2a, 519 TWL4030_BCIMDKEY); 520 if (bci->usb_enabled) { 521 pm_runtime_mark_last_busy(bci->transceiver->dev); ^^^^^^^^^^^^^^^^^^^^^ But we dereference it here. Possibly checking ->usb_enabled prevents a crash? 522 pm_runtime_put_autosuspend(bci->transceiver->dev); 523 bci->usb_enabled = 0; 524 } 525 bci->usb_cur = 0; 526 } 527 528 return ret; 529 } regards, dan carpenter