releases/4.4.13/clk-bcm2835-divider-value-has-to-be-1-or-more.patch

   1 From 997f16bd5d2e9b3456027f96fcadfe1e2bf12f4e Mon Sep 17 00:00:00 2001
   2 From: Martin Sperl <kernel@martin.sperl.org>
   3 Date: Mon, 29 Feb 2016 11:39:20 +0000
   4 Subject: clk: bcm2835: divider value has to be 1 or more
   5
   6 From: Martin Sperl <kernel@martin.sperl.org>
   7
   8 commit 997f16bd5d2e9b3456027f96fcadfe1e2bf12f4e upstream.
   9
  10 Current clamping of a normal divider allows a value < 1 to be valid.
  11
  12 A divider of < 1 would actually only be possible if we had a PLL...
  13
  14 So this patch clamps the divider to 1.
  15
  16 Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the
  17 audio domain clocks")
  18
  19 Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
  20 Signed-off-by: Eric Anholt <eric@anholt.net>
  21 Reviewed-by: Eric Anholt <eric@anholt.net>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23
  24 ---
  25  drivers/clk/bcm/clk-bcm2835.c |    5 +++--
  26  1 file changed, 3 insertions(+), 2 deletions(-)
  27
  28 --- a/drivers/clk/bcm/clk-bcm2835.c
  29 +++ b/drivers/clk/bcm/clk-bcm2835.c
  30 @@ -1181,8 +1181,9 @@ static u32 bcm2835_clock_choose_div(stru
  31                 div &= ~unused_frac_mask;
  32         }
  33
  34 -       /* Clamp to the limits. */
  35 -       div = max(div, unused_frac_mask + 1);
  36 +       /* clamp to min divider of 1 */
  37 +       div = max_t(u32, div, 1 << CM_DIV_FRAC_BITS);
  38 +       /* clamp to the highest possible fractional divider */
  39         div = min_t(u32, div, GENMASK(data->int_bits + CM_DIV_FRAC_BITS - 1,
  40                                       CM_DIV_FRAC_BITS - data->frac_bits));
  41