pinctrl: aspeed: Revert "Force to disable the function's signal"

This reverts commit cf517fef601b9dde151f0afc27164d13bf1fd907.

The commit cf517fef601b ("pinctrl: aspeed: Force to disable the
function's signal") exposed a problem with fetching the regmap for
reading the GFX register.

The Romulus machine the device tree contains a gpio hog for GPIO S7.
With the patch applied:

  Muxing pin 151 for GPIO
  Disabling signal VPOB9 for VPO
  aspeed-g5-pinctrl 1e6e2080.pinctrl: Failed to acquire regmap for IP block 1
  aspeed-g5-pinctrl 1e6e2080.pinctrl: request() failed for pin 151

The code path is aspeed-gpio -> pinmux-g5 -> regmap -> clk, and the
of_clock code returns an error as it doesn't have a valid struct clk_hw
pointer. The regmap call happens because pinmux wants to check the GFX
node (IP block 1) to query bits there.

For reference, before the offending patch:

  Muxing pin 151 for GPIO
  Disabling signal VPOB9 for VPO
  Want SCU8C[0x00000080]=0x1, got 0x0 from 0x00000000
  Disabling signal VPOB9 for VPOOFF1
  Want SCU8C[0x00000080]=0x1, got 0x0 from 0x00000000
  Disabling signal VPOB9 for VPOOFF2
  Want SCU8C[0x00000080]=0x1, got 0x0 from 0x00000000
  Enabling signal GPIOS7 for GPIOS7
  Muxed pin 151 as GPIOS7
  gpio-943 (seq_cont): hogged as output/low

We can't skip the clock check to allow pinmux to proceed, because the
write to disable VPOB9 will try to set a bit in the GFX register space
which will not stick when the IP is in reset. However, we do not want to
enable the IP just so pinmux can do a disable-enable dance for the pin.

For now, revert the offending patch while a correct solution is found.

Fixes: cf517fef601b ("pinctrl: aspeed: Force to disable the function's signal")
Link: https://github.com/openbmc/linux/issues/218
Signed-off-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20230130220845.917985-1-joel@jms.id.au
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/aspeed/pinctrl-aspeed.c b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
index b5ca450..9c6ee46 100644 (file)
--- a/drivers/pinctrl/aspeed/pinctrl-aspeed.c
+++ b/drivers/pinctrl/aspeed/pinctrl-aspeed.c
@@ -93,10 +93,19 @@ static int aspeed_sig_expr_enable(struct aspeed_pinmux_data *ctx,
 static int aspeed_sig_expr_disable(struct aspeed_pinmux_data *ctx,
                                   const struct aspeed_sig_expr *expr)
 {
+       int ret;
+
        pr_debug("Disabling signal %s for %s\n", expr->signal,
                 expr->function);
 
-       return aspeed_sig_expr_set(ctx, expr, false);
+       ret = aspeed_sig_expr_eval(ctx, expr, true);
+       if (ret < 0)
+               return ret;
+
+       if (ret)
+               return aspeed_sig_expr_set(ctx, expr, false);
+
+       return 0;
 }
 
 /**