From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751352AbcDNE77 (ORCPT ); Thu, 14 Apr 2016 00:59:59 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:51953 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751023AbcDNE75 (ORCPT ); Thu, 14 Apr 2016 00:59:57 -0400 From: Keerthy To: CC: , , , , , , , Subject: [PATCH v2] pinctrl: pinctrl-single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs Date: Thu, 14 Apr 2016 10:29:16 +0530 Message-ID: <1460609956-26539-1-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 --- Changes in v2: * Changed pcs->fshift to use __ffs instead of ffs to be consistent. Boot tesed on da850-evm and checked the pinctrl sysfs nodes. 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 fb126d5..cf9bafa 100644 --- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1280,9 +1280,9 @@ 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; @@ -1852,7 +1852,7 @@ 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. */ -- 1.9.1