diff options
Diffstat (limited to 'drivers/clk')
| -rw-r--r-- | drivers/clk/aspeed/clk_ast2500.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/clk/aspeed/clk_ast2500.c b/drivers/clk/aspeed/clk_ast2500.c index 2182320f607..dbee13a1829 100644 --- a/drivers/clk/aspeed/clk_ast2500.c +++ b/drivers/clk/aspeed/clk_ast2500.c @@ -165,6 +165,35 @@ static ulong ast2500_clk_get_rate(struct clk *clk) return rate; } +struct ast2500_clock_config { + ulong input_rate; + ulong rate; + struct ast2500_div_config cfg; +}; + +static const struct ast2500_clock_config ast2500_clock_config_defaults[] = { + { 24000000, 250000000, { .num = 124, .denum = 1, .post_div = 5 } }, +}; + +static bool ast2500_get_clock_config_default(ulong input_rate, + ulong requested_rate, + struct ast2500_div_config *cfg) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(ast2500_clock_config_defaults); i++) { + const struct ast2500_clock_config *default_cfg = + &ast2500_clock_config_defaults[i]; + if (default_cfg->input_rate == input_rate && + default_cfg->rate == requested_rate) { + *cfg = default_cfg->cfg; + return true; + } + } + + return false; +} + /* * @input_rate - the rate of input clock in Hz * @requested_rate - desired output rate in Hz @@ -189,6 +218,12 @@ static ulong ast2500_calc_clock_config(ulong input_rate, ulong requested_rate, ulong delta = rate_khz; ulong new_rate_khz = 0; + /* + * Look for a well known frequency first. + */ + if (ast2500_get_clock_config_default(input_rate, requested_rate, cfg)) + return requested_rate; + for (; it.denum <= max_vals.denum; ++it.denum) { for (it.post_div = 0; it.post_div <= max_vals.post_div; ++it.post_div) { @@ -318,6 +353,9 @@ static ulong ast2500_configure_d2pll(struct ast2500_scu *scu, ulong rate) /* * The values and the meaning of the next three * parameters are undocumented. Taken from Aspeed SDK. + * + * TODO(clg@kaod.org): the SIP and SIC values depend on the + * Numerator value */ const u32 d2_pll_ext_param = 0x2c; const u32 d2_pll_sip = 0x11; |