diff options
Diffstat (limited to 'drivers/clk/bcm')
| -rw-r--r-- | drivers/clk/bcm/clk-bcm2835.c | 67 |
1 files changed, 63 insertions, 4 deletions
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 2acaa77ad482..df96fe6dadab 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -436,6 +436,9 @@ struct bcm2835_clock_data { const char *const *parents; int num_mux_parents; + /* Bitmap encoding which parents accept rate change propagation. */ + unsigned int set_rate_parent; + u32 ctl_reg; u32 div_reg; @@ -1017,10 +1020,60 @@ bcm2835_clk_is_pllc(struct clk_hw *hw) return strncmp(clk_hw_get_name(hw), "pllc", 4) == 0; } +static unsigned long bcm2835_clock_choose_div_and_prate(struct clk_hw *hw, + int parent_idx, + unsigned long rate, + u32 *div, + unsigned long *prate) +{ + struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw); + struct bcm2835_cprman *cprman = clock->cprman; + const struct bcm2835_clock_data *data = clock->data; + unsigned long best_rate; + u32 curdiv, mindiv, maxdiv; + struct clk_hw *parent; + + parent = clk_hw_get_parent_by_index(hw, parent_idx); + + if (!(BIT(parent_idx) & data->set_rate_parent)) { + *prate = clk_hw_get_rate(parent); + *div = bcm2835_clock_choose_div(hw, rate, *prate, true); + + return bcm2835_clock_rate_from_divisor(clock, *prate, + *div); + } + + if (data->frac_bits) + dev_warn(cprman->dev, + "frac bits are not used when propagating rate change"); + + /* clamp to min divider of 2 if we're dealing with a mash clock */ + mindiv = data->is_mash_clock ? 2 : 1; + maxdiv = BIT(data->int_bits) - 1; + + /* TODO: Be smart, and only test a subset of the available divisors. */ + for (curdiv = mindiv; curdiv <= maxdiv; curdiv++) { + unsigned long tmp_rate; + + tmp_rate = clk_hw_round_rate(parent, rate * curdiv); + tmp_rate /= curdiv; + if (curdiv == mindiv || + (tmp_rate > best_rate && tmp_rate <= rate)) + best_rate = tmp_rate; + + if (best_rate == rate) + break; + } + + *div = curdiv << CM_DIV_FRAC_BITS; + *prate = curdiv * best_rate; + + return best_rate; +} + static int bcm2835_clock_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) { - struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw); struct clk_hw *parent, *best_parent = NULL; bool current_parent_is_pllc; unsigned long rate, best_rate = 0; @@ -1048,9 +1101,8 @@ static int bcm2835_clock_determine_rate(struct clk_hw *hw, if (bcm2835_clk_is_pllc(parent) && !current_parent_is_pllc) continue; - prate = clk_hw_get_rate(parent); - div = bcm2835_clock_choose_div(hw, req->rate, prate, true); - rate = bcm2835_clock_rate_from_divisor(clock, prate, div); + rate = bcm2835_clock_choose_div_and_prate(hw, i, req->rate, + &div, &prate); if (rate > best_rate && rate <= req->rate) { best_parent = parent; best_prate = prate; @@ -1262,6 +1314,13 @@ static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman, init.name = data->name; init.flags = data->flags | CLK_IGNORE_UNUSED; + /* + * Pass the CLK_SET_RATE_PARENT flag if we are allowed to propagate + * rate changes on at least of the parents. + */ + if (data->set_rate_parent) + init.flags |= CLK_SET_RATE_PARENT; + if (data->is_vpu_clock) { init.ops = &bcm2835_vpu_clock_clk_ops; } else { |