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

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

[Eddie James]

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

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

[Stephen Boyd]

Quoting Eddie James (2020-04-08 13:36:16)
> 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>

Any Fixes tag for this patch? Seems like it is fixing something.

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

[Joel Stanley]

On Wed, 27 May 2020 at 08:15, Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Eddie James (2020-04-08 13:36:16)
> > 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>
>
> Any Fixes tag for this patch? Seems like it is fixing something.

It fixes the driver to work on the new hardware that didn't exist
until now. I guess you could say:

Fixes: d3d04f6c330a ("clk: Add support for AST2600 SoC")

Cheers,

Joel

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

[Stephen Boyd]

Quoting Eddie James (2020-04-08 13:36:16)
> 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>
> ---

Applied to clk-next