From: Claudiu Beznea claudiu.beznea@microchip.com
[ Upstream commit facb87ad75603813bc3b1314f5a87377f020fcb8 ]
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... Acked-by: Nicolas Ferre nicolas.ferre@microchip.com Signed-off-by: Stephen Boyd sboyd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/clk/at91/sama7g5.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/clk/at91/sama7g5.c b/drivers/clk/at91/sama7g5.c index 9e1ec48c44747..9c05ecb760b79 100644 --- a/drivers/clk/at91/sama7g5.c +++ b/drivers/clk/at91/sama7g5.c @@ -982,16 +982,7 @@ 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, 0); if (IS_ERR(hw))