[PATCH] clk: ast2600: Fix AHB clock divider for A1

[Eddie James <eajames@linux.ibm.com>]

The latest specs for the AST2600 A1 chip include some different bit
definitions for calculating the AHB clock divider. Implement these in
order to get the correct AHB clock value in Linux.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/clk/clk-ast2600.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk-ast2600.c b/drivers/clk/clk-ast2600.c
index 392d01705b97..99afc949925f 100644
--- a/drivers/clk/clk-ast2600.c
+++ b/drivers/clk/clk-ast2600.c
@@ -642,14 +642,22 @@ static const u32 ast2600_a0_axi_ahb_div_table[] = {
 	2, 2, 3, 5,
 };
 
-static const u32 ast2600_a1_axi_ahb_div_table[] = {
-	4, 6, 2, 4,
+static const u32 ast2600_a1_axi_ahb_div0_tbl[] = {
+	3, 2, 3, 4,
+};
+
+static const u32 ast2600_a1_axi_ahb_div1_tbl[] = {
+	3, 4, 6, 8,
+};
+
+static const u32 ast2600_a1_axi_ahb200_tbl[] = {
+	3, 4, 3, 4, 2, 2, 2, 2,
 };
 
 static void __init aspeed_g6_cc(struct regmap *map)
 {
 	struct clk_hw *hw;
-	u32 val, div, chip_id, axi_div, ahb_div;
+	u32 val, div, divbits, chip_id, axi_div, ahb_div;
 
 	clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, 25000000);
 
@@ -679,11 +687,22 @@ static void __init aspeed_g6_cc(struct regmap *map)
 	else
 		axi_div = 2;
 
+	divbits = (val >> 11) & 0x3;
 	regmap_read(map, ASPEED_G6_SILICON_REV, &chip_id);
-	if (chip_id & BIT(16))
-		ahb_div = ast2600_a1_axi_ahb_div_table[(val >> 11) & 0x3];
-	else
+	if (chip_id & BIT(16)) {
+		if (!divbits) {
+			ahb_div = ast2600_a1_axi_ahb200_tbl[(val >> 8) & 0x3];
+			if (val & BIT(16))
+				ahb_div *= 2;
+		} else {
+			if (val & BIT(16))
+				ahb_div = ast2600_a1_axi_ahb_div1_tbl[divbits];
+			else
+				ahb_div = ast2600_a1_axi_ahb_div0_tbl[divbits];
+		}
+	} else {
 		ahb_div = ast2600_a0_axi_ahb_div_table[(val >> 11) & 0x3];
+	}
 
 	hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, axi_div * ahb_div);
 	aspeed_g6_clk_data->hws[ASPEED_CLK_AHB] = hw;
-- 
2.24.0