[PATCH] clk: rockchip: rk3066: uart0/1 pclk comes from hclk_ahb2apb

[PATCH] clk: rockchip: rk3066: uart0/1 pclk comes from hclk_ahb2apb

[Yalçın Can]

On rk3066a, uart0 (0x10124000) and uart1 (0x10126000) sit behind the
AHB-to-APB bridge of the cpu bus, as on rk3188, but their pclk gates name
pclk_cpu as parent. Nothing then holds hclk_ahb2apb (CLKGATE_CON4 bit 9),
so it is switched off as unused at late init and both UARTs read back as
all zeros: 8250 autoconfig reports PORT_UNKNOWN for uart0 and a serdev
Bluetooth controller on it (brcm,bcm4330-bt) times out on every command.

The vendor 3.0 kernel uses the same parent, but models ahb2apb as a
divider without a gate, so it is never turned off there.

Make hclk_ahb2apb the parent of pclk_uart0/1, as the rk3188 table already
does.

Tested on an RK3066a board (MK808B, BCM4330 Bluetooth on uart0): before,
CLKGATE_CON4 reads 0x6200, uart0 registers read 0 and ttyS0 is
PORT_UNKNOWN; clearing bit 9 by hand makes it probe as a 16550A. With this
patch uart0 probes as a 16550A at boot, hci_bcm loads its firmware patch,
and LE and BR/EDR scans find other devices. uart1 is not wired on this
board and was not tested.

Fixes: 2c14736c75db ("clk: rockchip: add clock driver for rk3188 and rk3066 clocks")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Yalçın Can <ylcncn@gmail.com>
---
 drivers/clk/rockchip/clk-rk3188.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/rockchip/clk-rk3188.c b/drivers/clk/rockchip/clk-rk3188.c
index 318c8ddc8..680c33a62 100644
--- a/drivers/clk/rockchip/clk-rk3188.c
+++ b/drivers/clk/rockchip/clk-rk3188.c
@@ -649,8 +649,9 @@ static struct rockchip_clk_branch rk3066a_clk_branches[] __initdata = {
 	GATE(PCLK_TIMER1, "pclk_timer1", "pclk_cpu", 0, RK2928_CLKGATE_CON(7), 8, GFLAGS),
 	GATE(PCLK_TIMER2, "pclk_timer2", "pclk_cpu", 0, RK2928_CLKGATE_CON(7), 9, GFLAGS),
 	GATE(PCLK_GPIO6, "pclk_gpio6", "pclk_cpu", 0, RK2928_CLKGATE_CON(8), 15, GFLAGS),
-	GATE(PCLK_UART0, "pclk_uart0", "pclk_cpu", 0, RK2928_CLKGATE_CON(8), 0, GFLAGS),
-	GATE(PCLK_UART1, "pclk_uart1", "pclk_cpu", 0, RK2928_CLKGATE_CON(8), 1, GFLAGS),
+	/* uart0/1 sit behind the AHB-to-APB bridge, as on rk3188 */
+	GATE(PCLK_UART0, "pclk_uart0", "hclk_ahb2apb", 0, RK2928_CLKGATE_CON(8), 0, GFLAGS),
+	GATE(PCLK_UART1, "pclk_uart1", "hclk_ahb2apb", 0, RK2928_CLKGATE_CON(8), 1, GFLAGS),
 
 	GATE(PCLK_GPIO4, "pclk_gpio4", "pclk_peri", 0, RK2928_CLKGATE_CON(8), 13, GFLAGS),
 	GATE(PCLK_TSADC, "pclk_tsadc", "pclk_peri", 0, RK2928_CLKGATE_CON(4), 13, GFLAGS),
-- 
2.47.3