clk: ralink: mtmips: add mmc related clocks for SoCs MT7620, MT7628 and MT7688

Original architecture clock code from where this driver was derived did not
include nothing related to mmc clocks. OpenWRT people started to use mtk-sd
upstream driver recently and they were forced to use a dts 'fixed-clock'
node with 48 MHz clock:
- https://github.com/openwrt/openwrt/pull/15896
The proper thing to do to avoid that is to add the mmc related clocks to the
driver to avoid a dts with fixed clocks nodes. The minimal documentation in
the mt7620 programming guide says that there is a BBP_PLL clock of 480 MHz
derived from the 40 MHz XTAL and from there a clock divider by ten produces
the desired SDHC clock of 48 MHz for the mmc. Hence add a fixed clock 'bbppll'
and factor clock 'sdhc' ten divider child to properly set the 'mmc' peripheral
clock with the desired 48 Mhz rate.

Signed-off-by: Sergio Paracuellos <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/ralink/clk-mtmips.c

···
 	{ CLK_PERIPH("10000b00.spi", "bus") },
 	{ CLK_PERIPH("10000b40.spi", "bus") },
 	{ CLK_PERIPH("10000c00.uartlite", "periph") },
+	{ CLK_PERIPH("10130000.mmc", "sdhc") },
 	{ CLK_PERIPH("10180000.wmac", "xtal") }
 };
 
···
 	{ CLK_PERIPH("10000c00.uart0", "periph") },
 	{ CLK_PERIPH("10000d00.uart1", "periph") },
 	{ CLK_PERIPH("10000e00.uart2", "periph") },
+	{ CLK_PERIPH("10130000.mmc", "sdhc") },
 	{ CLK_PERIPH("10300000.wmac", "xtal") }
 };
 
···
 	CLK_FIXED("periph", "xtal", 40000000)
 };
 
+static struct mtmips_clk_fixed mt7620_fixed_clocks[] = {
+	CLK_FIXED("bbppll", "xtal", 480000000)
+};
+
 static struct mtmips_clk_fixed mt76x8_fixed_clocks[] = {
-	CLK_FIXED("pcmi2s", "xtal", 480000000),
+	CLK_FIXED("bbppll", "xtal", 480000000),
+	CLK_FIXED("pcmi2s", "bbppll", 480000000),
 	CLK_FIXED("periph", "xtal", 40000000)
 };
 
···
 
 static struct mtmips_clk_factor rt305x_factor_clocks[] = {
 	CLK_FACTOR("bus", "cpu", 1, 3)
+};
+
+static struct mtmips_clk_factor mt7620_factor_clocks[] = {
+	CLK_FACTOR("sdhc", "bbppll", 1, 10)
+};
+
+static struct mtmips_clk_factor mt76x8_factor_clocks[] = {
+	CLK_FACTOR("bus", "cpu", 1, 3),
+	CLK_FACTOR("sdhc", "bbppll", 1, 10)
 };
 
 static int mtmips_register_factor_clocks(struct clk_hw_onecell_data *clk_data,
···
 static const struct mtmips_clk_data mt7620_clk_data = {
 	.clk_base = mt7620_clks_base,
 	.num_clk_base = ARRAY_SIZE(mt7620_clks_base),
-	.clk_fixed = NULL,
-	.num_clk_fixed = 0,
-	.clk_factor = NULL,
-	.num_clk_factor = 0,
+	.clk_fixed = mt7620_fixed_clocks,
+	.num_clk_fixed = ARRAY_SIZE(mt7620_fixed_clocks),
+	.clk_factor = mt7620_factor_clocks,
+	.num_clk_factor = ARRAY_SIZE(mt7620_factor_clocks),
 	.clk_periph = mt7620_pherip_clks,
 	.num_clk_periph = ARRAY_SIZE(mt7620_pherip_clks),
 };
···
 	.num_clk_base = ARRAY_SIZE(mt76x8_clks_base),
 	.clk_fixed = mt76x8_fixed_clocks,
 	.num_clk_fixed = ARRAY_SIZE(mt76x8_fixed_clocks),
-	.clk_factor = rt305x_factor_clocks,
-	.num_clk_factor = ARRAY_SIZE(rt305x_factor_clocks),
+	.clk_factor = mt76x8_factor_clocks,
+	.num_clk_factor = ARRAY_SIZE(mt76x8_factor_clocks),
 	.clk_periph = mt76x8_pherip_clks,
 	.num_clk_periph = ARRAY_SIZE(mt76x8_pherip_clks),
 };