Commit e1e3e700 authored Jul 22, 2020 by Claudiu Beznea Committed by Stephen Boyd Jul 24, 2020

clk: at91: sckc: register slow_rc with accuracy option

Chapter 57.7.5 of SAM9X60 datasheet specifies that the maximum drift of
this oscillator is +- 3KHz. Use that value and the formula at [1]
or the calculator at [2] to compute the PPB value.

[1] https://www.everythingrf.com/rf-calculators/ppm-to-hz-calculator
[2] https://www.changpuak.ch/electronics/ppm_to_Hz_converter.php



Fixes: 04bcc427 ("clk: at91: sckc: add support for SAM9X60")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-9-git-send-email-claudiu.beznea@microchip.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>

parent 172e7dde

drivers/clk/at91/sckc.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -471,8 +471,9 @@ static void __init of_sam9x60_sckc_setup(struct device_node *np)
		if (!regbase)
		return;

		slow_rc = clk_hw_register_fixed_rate(NULL, parent_names[0], NULL, 0,
		32768);
		slow_rc = clk_hw_register_fixed_rate_with_accuracy(NULL, parent_names[0],
		NULL, 0, 32768,
		93750000);
		if (IS_ERR(slow_rc))
		return;

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