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clk: at91: sama7g5: remove prescaler part of master clock

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On SAMA7G5 the prescaler part of master clock has been implemented as a
changeable one. Everytime the prescaler is changed the PMC_SR.MCKRDY bit
must be polled. Value 1 for PMC_SR.MCKRDY means the prescaler update is
done. Driver polls for this bit until it becomes 1. On SAMA7G5 it has
been discovered that in some conditions the PMC_SR.MCKRDY is not rising
but the rate it provides it's stable. The workaround is to add a timeout
when polling for PMC_SR.MCKRDY. At the moment, for SAMA7G5, the prescaler
will be removed from Linux clock tree as all the frequencies for CPU could
be obtained from PLL and also there will be less overhead when changing
frequency via DVFS.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-14-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Claudiu Beznea 2021-10-11 14:27:17 +03:00 committed by Stephen Boyd
parent 7029db09b2
commit facb87ad75
1 changed files with 1 additions and 10 deletions
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11
drivers/clk/at91/sama7g5.c
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@ -992,16 +992,7 @@ static void __init sama7g5_pmc_setup(struct device_node *np)
}
parent_names[0] = "cpupll_divpmcck";
hw = at91_clk_register_master_pres(regmap, "cpuck", 1, parent_names,
&mck0_layout, &mck0_characteristics,
&pmc_mck0_lock,
CLK_SET_RATE_PARENT, 0);
if (IS_ERR(hw))
goto err_free;
sama7g5_pmc->chws[PMC_CPU] = hw;
hw = at91_clk_register_master_div(regmap, "mck0", "cpuck",
hw = at91_clk_register_master_div(regmap, "mck0", "cpupll_divpmcck",
&mck0_layout, &mck0_characteristics,
&pmc_mck0_lock, CLK_GET_RATE_NOCACHE, 5);
if (IS_ERR(hw))