| From d85a46553fb6b149fe116b8d8294d68a3ccbb0f1 Mon Sep 17 00:00:00 2001 |
| From: Alan Hung <yung-sheng.huang@fii-na.corp-partner.google.com> |
| Date: Wed, 25 Feb 2026 11:08:49 +0800 |
| Subject: [PATCH] SGPIO: Make default output values persist reboot |
| |
| Summary: |
| Following an AC cycle, the SGPIO default values are set. The unit |
| will function as expected. However following a reboot, the SGPIO |
| controller will still be operating. The SGPIO values will be zeroed out |
| for a short amount of time, and undefined behavior will occur. |
| |
| Make the SGPIO output values persist reboot, and only set the default |
| SGPIO output values if not previously set. |
| |
| Google-Bug-Id: 458611169, 471067239 |
| Change-Id: Ifc3edb7384faf2c29f5714b289903c7d2b1fe83b |
| Signed-off-by: Kyle Nieman <kyle.nieman@fii-na.corp-partner.google.com> |
| Signed-off-by: Alan Hung <yung-sheng.huang@fii-na.corp-partner.google.com> |
| --- |
| drivers/gpio/gpio-aspeed-sgpio.c | 14 +++++++++++++- |
| 1 file changed, 13 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/gpio/gpio-aspeed-sgpio.c b/drivers/gpio/gpio-aspeed-sgpio.c |
| index 6a928a182b19..a0104052fafb 100644 |
| --- a/drivers/gpio/gpio-aspeed-sgpio.c |
| +++ b/drivers/gpio/gpio-aspeed-sgpio.c |
| @@ -874,11 +874,23 @@ static int aspeed_sgpio_probe(struct platform_device *pdev) |
| ast_write_bits(addr, SGPIO_G7_SERIAL_OUT_SEL, |
| SELECT_FROM_CSR); |
| |
| - if (has_default) { |
| + /* |
| + * By default, GPIO values set in user space will |
| + * automatically be set to be retained across BMC |
| + * reboot. Apply this for initially set values of SGPIO |
| + * as well. Only set the default value if the value is |
| + * not set to persist BMC reboot. This is so that |
| + * if the values were changed from the default defined, |
| + * we aren't accidently overwritting them. |
| + */ |
| + int has_persistent_output = field_get(SGPIO_G7_RST_TOLERANCE, ioread32(addr)); |
| + if (has_default && !has_persistent_output) { |
| const int byte_index = i / 8; |
| const int bit_index = i % 8; |
| initial_val = (byte_configs[byte_index] >> bit_index) & 1; |
| ast_write_bits(addr, SGPIO_G7_OUT_DATA, initial_val); |
| + // Retain set values across BMC reboots |
| + ast_write_bits(addr, SGPIO_G7_RST_TOLERANCE, 1); |
| } |
| } |
| |
| -- |
| 2.34.1 |
| |
