From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965777AbcDMHCZ (ORCPT ); Wed, 13 Apr 2016 03:02:25 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:57255 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933090AbcDMHCX (ORCPT ); Wed, 13 Apr 2016 03:02:23 -0400 From: Keerthy To: CC: , , , , , , , Subject: [PATCH] pinctrl: pinctrl-single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs Date: Wed, 13 Apr 2016 12:31:05 +0530 Message-ID: <1460530865-29085-1-git-send-email-j-keerthy@ti.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pcs_parse_bits_in_pinctrl_entry uses ffs which gives bit indices ranging from 1 to MAX. This leads to a corner case where we try to request the pin number = MAX and fails. bit_pos value is being calculted using ffs. pin_num_from_lsb uses bit_pos value. pins array is populated with: pin + pin_num_from_lsb. The above is 1 more than usual bit indices as bit_pos uses ffs to compute first set bit. Hence the last of the pins array is populated with the MAX value and not MAX - 1 which causes error when we call pin_request. mask_pos is rightly calculated as ((pcs->fmask) << (bit_pos - 1)) Consequently val_pos and submask are correct. Hence use __ffs which gives (ffs(x) - 1) as the first bit set. fixes: 4e7e8017a8 ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules") Signed-off-by: Keerthy --- Boot tested on da850-evm drivers/pinctrl/pinctrl-single.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c index 748c047..897b89b 100644 --- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1323,9 +1323,9 @@ static int pcs_parse_bits_in_pinctrl_entry(struct pcs_device *pcs, /* Parse pins in each row from LSB */ while (mask) { - bit_pos = ffs(mask); + bit_pos = __ffs(mask); pin_num_from_lsb = bit_pos / pcs->bits_per_pin; - mask_pos = ((pcs->fmask) << (bit_pos - 1)); + mask_pos = ((pcs->fmask) << bit_pos); val_pos = val & mask_pos; submask = mask & mask_pos; -- 1.9.1