The stmpe_reg_read function can fail, but its return value is not checked in stmpe_gpio_irq_sync_unlock. This can lead to silent failures and incorrect behavior if the hardware access fails.

This patch adds checks for the return value of stmpe_reg_read. If the function fails, an error message is logged and the function returns early to avoid further issues.

Fixes: b888fb6f2a27 ("gpio: stmpe: i2c transfer are forbiden in atomic context") Cc: stable@vger.kernel.org # 4.16+ Signed-off-by: Wentao Liang vulab@iscas.ac.cn --- drivers/gpio/gpio-stmpe.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c index 75a3633ceddb..222279a9d82b 100644 --- a/drivers/gpio/gpio-stmpe.c +++ b/drivers/gpio/gpio-stmpe.c @@ -191,7 +191,7 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d) [REG_IE][CSB] = STMPE_IDX_IEGPIOR_CSB, [REG_IE][MSB] = STMPE_IDX_IEGPIOR_MSB, }; - int i, j; + int ret, i, j;

/* * STMPE1600: to be able to get IRQ from pins, @@ -199,8 +199,16 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d) * GPSR or GPCR registers */ if (stmpe->partnum == STMPE1600) { - stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_LSB]); - stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_CSB]); + ret = stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_LSB]); + if (ret < 0) { + dev_err(stmpe->dev, "Failed to read GPMR_LSB: %d\n", ret); + goto err; + } + ret = stmpe_reg_read(stmpe, stmpe->regs[STMPE_IDX_GPMR_CSB]); + if (ret < 0) { + dev_err(stmpe->dev, "Failed to read GPMR_CSB: %d\n", ret); + goto err; + } }

for (i = 0; i < CACHE_NR_REGS; i++) { @@ -222,6 +230,7 @@ static void stmpe_gpio_irq_sync_unlock(struct irq_data *d) } }

+err: mutex_unlock(&stmpe_gpio->irq_lock); }