From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Mon, 14 Jun 2021 23:02:45 +0100 Subject: drv:rtc:sun6i: support RTCs without external LOSCs Some newer Allwinner RTCs (for instance the one in the H616 SoC) lack a pin for an external 32768 Hz oscillator. As a consequence, this LOSC can't be selected as the RTC clock source, and we must rely on the internal RC oscillator. To allow additions of clocks to the RTC node, add a feature bit to ignore any provided clocks for now (the current code would think this is the external LOSC). Later DTs and code can then for instance add the PLL based clock input, and older kernel won't get confused. Signed-off-by: Andre Przywara Acked-by: Jernej Skrabec --- drivers/rtc/rtc-sun6i.c | 16 +++++++--- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c index 02129ea346c1..190ea007d82e 100644 --- a/drivers/rtc/rtc-sun6i.c +++ b/drivers/rtc/rtc-sun6i.c @@ -137,6 +137,7 @@ struct sun6i_rtc_clk_data { unsigned int has_out_clk : 1; unsigned int has_losc_en : 1; unsigned int has_auto_swt : 1; + unsigned int no_ext_losc : 1; }; #define RTC_LINEAR_DAY BIT(0) @@ -260,7 +261,7 @@ static void __init sun6i_rtc_clk_init(struct device_node *node, } /* Switch to the external, more precise, oscillator, if present */ - if (of_property_present(node, "clocks")) { + if (!rtc->data->no_ext_losc && of_get_property(node, "clocks", NULL)) { reg |= SUN6I_LOSC_CTRL_EXT_OSC; if (rtc->data->has_losc_en) reg |= SUN6I_LOSC_CTRL_EXT_LOSC_EN; @@ -284,14 +285,19 @@ static void __init sun6i_rtc_clk_init(struct device_node *node, } parents[0] = clk_hw_get_name(rtc->int_osc); - /* If there is no external oscillator, this will be NULL and ... */ - parents[1] = of_clk_get_parent_name(node, 0); + if (rtc->data->no_ext_losc) { + parents[1] = NULL; + init.num_parents = 1; + } else { + /* If there is no external oscillator, this will be NULL and */ + parents[1] = of_clk_get_parent_name(node, 0); + /* ... number of clock parents will be 1. */ + init.num_parents = of_clk_get_parent_count(node) + 1; + } rtc->hw.init = &init; init.parent_names = parents; - /* ... number of clock parents will be 1. */ - init.num_parents = of_clk_get_parent_count(node) + 1; of_property_read_string_index(node, "clock-output-names", 0, &init.name); -- Armbian