git.openwrt.org Git - openwrt/staging/xback.git/blob

   1 From c6c55ad6f9269c703e8b7f9832640dbc0390238a Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Thu, 2 May 2019 15:24:04 -0700
   4 Subject: [PATCH] clk: bcm2835: Allow reparenting leaf clocks while
   5  they're running.
   6
   7 This falls under the same "we can reprogram glitch-free as long as we
   8 pause generation" rule as updating the div/frac fields.  This can be
   9 used for runtime reclocking of V3D to manage power leakage.
  10
  11 Signed-off-by: Eric Anholt <eric@anholt.net>
  12 ---
  13  drivers/clk/bcm/clk-bcm2835.c | 19 ++++++++++++++++---
  14  1 file changed, 16 insertions(+), 3 deletions(-)
  15
  16 --- a/drivers/clk/bcm/clk-bcm2835.c
  17 +++ b/drivers/clk/bcm/clk-bcm2835.c
  18 @@ -1104,8 +1104,10 @@ static int bcm2835_clock_on(struct clk_h
  19         return 0;
  20  }
  21
  22 -static int bcm2835_clock_set_rate(struct clk_hw *hw,
  23 -                                 unsigned long rate, unsigned long parent_rate)
  24 +static int bcm2835_clock_set_rate_and_parent(struct clk_hw *hw,
  25 +                                            unsigned long rate,
  26 +                                            unsigned long parent_rate,
  27 +                                            u8 parent)
  28  {
  29         struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
  30         struct bcm2835_cprman *cprman = clock->cprman;
  31 @@ -1127,6 +1129,11 @@ static int bcm2835_clock_set_rate(struct
  32                 bcm2835_clock_wait_busy(clock);
  33         }
  34
  35 +       if (parent != 0xff) {
  36 +               ctl &= ~(CM_SRC_MASK << CM_SRC_SHIFT);
  37 +               ctl |= parent << CM_SRC_SHIFT;
  38 +       }
  39 +
  40         ctl &= ~CM_FRAC;
  41         ctl |= (div & CM_DIV_FRAC_MASK) ? CM_FRAC : 0;
  42         cprman_write(cprman, data->ctl_reg, ctl);
  43 @@ -1138,6 +1145,12 @@ static int bcm2835_clock_set_rate(struct
  44         return 0;
  45  }
  46
  47 +static int bcm2835_clock_set_rate(struct clk_hw *hw,
  48 +                                 unsigned long rate, unsigned long parent_rate)
  49 +{
  50 +       return bcm2835_clock_set_rate_and_parent(hw, rate, parent_rate, 0xff);
  51 +}
  52 +
  53  static bool
  54  bcm2835_clk_is_pllc(struct clk_hw *hw)
  55  {
  56 @@ -1321,6 +1334,7 @@ static const struct clk_ops bcm2835_cloc
  57         .unprepare = bcm2835_clock_off,
  58         .recalc_rate = bcm2835_clock_get_rate,
  59         .set_rate = bcm2835_clock_set_rate,
  60 +       .set_rate_and_parent = bcm2835_clock_set_rate_and_parent,
  61         .determine_rate = bcm2835_clock_determine_rate,
  62         .set_parent = bcm2835_clock_set_parent,
  63         .get_parent = bcm2835_clock_get_parent,
  64 @@ -1503,7 +1517,6 @@ static struct clk_hw *bcm2835_register_c
  65                 init.ops = &bcm2835_vpu_clock_clk_ops;
  66         } else {
  67                 init.ops = &bcm2835_clock_clk_ops;
  68 -               init.flags |= CLK_SET_PARENT_GATE;
  69
  70                 /* If the clock wasn't actually enabled at boot, it's not
  71                  * critical.