[PATCH 2/2] clk: mediatek: mt7629: add RTC clock selection

[Chuanhong Guo <gch981213@gmail.com>]

CLK_MODE bits 3:2 select the RTC clock source. Selector 0 uses the
40 MHz crystal divided by 1024, while selector 3 divides it by 1221
to provide approximately 32.76 kHz. The integrated Wi-Fi needs this
/1221 source.

Add the /1221 fixed-factor clock and the RTC mux so device trees can
select this source through assigned-clock-parents. Keep CLK_TOP_RTC
for the existing /1024 source.

Selector 1 is reserved. Selector 2 is documented as an approximately
25 kHz PMU bandgap clock, but its source and control are not sufficiently
described to model it here. Leave these entries unmodelled while
preserving the hardware selector values.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
---
 drivers/clk/mediatek/clk-mt7629.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/clk/mediatek/clk-mt7629.c b/drivers/clk/mediatek/clk-mt7629.c
index e154771b1b8b..6336f8c4167b 100644
--- a/drivers/clk/mediatek/clk-mt7629.c
+++ b/drivers/clk/mediatek/clk-mt7629.c
@@ -285,6 +285,10 @@ static const char * const infra_mux1_parents[] = {
 	"armpll"
 };
 
+static const char * const rtc_parents[] = {
+	"rtc", "clk_null", "clk_null", "rtc_32k"
+};
+
 static const struct mtk_gate_regs apmixed_cg_regs = {
 	.set_ofs = 0x8,
 	.clr_ofs = 0x8,
@@ -367,6 +371,7 @@ static const struct mtk_fixed_factor top_divs[] = {
 	FACTOR(CLK_TOP_ETH_500M, "eth_500m", "eth1pll", 1, 1),
 	FACTOR(CLK_TOP_TXCLK_SRC_PRE, "txclk_src_pre", "sgmiipll_d2", 1, 1),
 	FACTOR(CLK_TOP_RTC, "rtc", "clkxtal", 1, 1024),
+	FACTOR(CLK_TOP_RTC_32K, "rtc_32k", "clkxtal", 1, 1221),
 	FACTOR(CLK_TOP_PWM_QTR_26M, "pwm_qtr_26m", "clkxtal", 1, 1),
 	FACTOR(CLK_TOP_CPUM_TCK_IN, "cpum_tck_in", "cpum_tck", 1, 1),
 	FACTOR(CLK_TOP_TO_USB3_DA_TOP, "to_usb3_da_top", "clkxtal", 1, 1),
@@ -458,6 +463,8 @@ static struct mtk_composite infra_muxes[] = {
 };
 
 static struct mtk_composite top_muxes[] = {
+	/* CLK_MODE */
+	MUX(CLK_TOP_RTC_SEL, "rtc_sel", rtc_parents, 0x000, 2, 2),
 	/* CLK_CFG_0 */
 	MUX_GATE(CLK_TOP_AXI_SEL, "axi_sel", axi_parents,
 		 0x040, 0, 3, 7),

-- 
2.55.0