| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 060/163] pinctrl: single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs | Date | Mon, 2 May 2016 17:11:28 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Keerthy <j-keerthy@ti.com>
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 <j-keerthy@ti.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/pinctrl/pinctrl-single.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1273,9 +1273,9 @@ static int pcs_parse_bits_in_pinctrl_ent /* 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; @@ -1847,7 +1847,7 @@ static int pcs_probe(struct platform_dev 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. */
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