[PATCH v2 1/2] pinctrl: mcp23s08: Initialize mcp->dev and mcp->addr before regmap init

From: Judith Mendez

Date: Wed May 13 2026 - 19:12:20 EST


Regmap initialization triggers regcache_maple_populate() which attempts
SPI read to populate cache. SPI read requires mcp->dev and mcp->addr to
be set, without them, NULL pointer dereference occurs during probe.

Move initialization before mcp23s08_spi_regmap_init() call.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: f9f4fda15e72 ("pinctrl: mcp23s08: init reg_defaults from HW at probe and switch cache type")
Signed-off-by: Judith Mendez <jm@xxxxxx>
---
Changes since v1:
- Add #define for base adress & use instead of 0x40 hardcode base address
---
drivers/pinctrl/pinctrl-mcp23s08_spi.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/pinctrl-mcp23s08_spi.c b/drivers/pinctrl/pinctrl-mcp23s08_spi.c
index 54f61c8cb1c0f..5ed368772adb7 100644
--- a/drivers/pinctrl/pinctrl-mcp23s08_spi.c
+++ b/drivers/pinctrl/pinctrl-mcp23s08_spi.c
@@ -10,6 +10,7 @@
#include "pinctrl-mcp23s08.h"

#define MCP_MAX_DEV_PER_CS 8
+#define MCP23S08_SPI_BASE 0x40

/*
* A given spi_device can represent up to eight mcp23sxx chips
@@ -173,6 +174,8 @@ static int mcp23s08_probe(struct spi_device *spi)
for_each_set_bit(addr, &spi_present_mask, MCP_MAX_DEV_PER_CS) {
data->mcp[addr] = &data->chip[--chips];
data->mcp[addr]->irq = spi->irq;
+ data->mcp[addr]->dev = dev;
+ data->mcp[addr]->addr = MCP23S08_SPI_BASE | (addr << 1);

ret = mcp23s08_spi_regmap_init(data->mcp[addr], dev, addr, info);
if (ret)
@@ -184,7 +187,7 @@ static int mcp23s08_probe(struct spi_device *spi)
if (!data->mcp[addr]->pinctrl_desc.name)
return -ENOMEM;

- ret = mcp23s08_probe_one(data->mcp[addr], dev, 0x40 | (addr << 1),
+ ret = mcp23s08_probe_one(data->mcp[addr], dev, MCP23S08_SPI_BASE | (addr << 1),
info->type, -1);
if (ret < 0)
return ret;
--
2.54.0