Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754015AbcDZU1j (ORCPT ); Tue, 26 Apr 2016 16:27:39 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:58525 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752493AbcDZU0T (ORCPT ); Tue, 26 Apr 2016 16:26:19 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Keerthy , Linus Walleij , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 60/66] pinctrl: single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs Date: Tue, 26 Apr 2016 13:24:51 -0700 Message-Id: <1461702297-7792-61-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461702297-7792-1-git-send-email-kamal@canonical.com> References: <1461702297-7792-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2317 Lines: 62 3.19.8-ckt20 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Keerthy commit 56b367c0cd67d4c3006738e7dc9dda9273fd2bfe upstream. 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 Acked-by: Tony Lindgren Signed-off-by: Linus Walleij Signed-off-by: Kamal Mostafa --- drivers/pinctrl/pinctrl-single.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c index 772f7c4..64ac7b1 100644 --- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1273,9 +1273,9 @@ 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; @@ -1851,7 +1851,7 @@ static int pcs_probe(struct platform_device *pdev) ret = of_property_read_u32(np, "pinctrl-single,function-mask", &pcs->fmask); if (!ret) { - pcs->fshift = ffs(pcs->fmask) - 1; + pcs->fshift = __ffs(pcs->fmask); pcs->fmax = pcs->fmask >> pcs->fshift; } else { /* If mask property doesn't exist, function mux is invalid. */ -- 2.7.4