diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c index 1951b5967aa9..76cc698055cd 100644 --- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -83,18 +83,26 @@ struct lpss_private_data { u32 prv_reg_ctx[LPSS_PRV_REG_COUNT]; }; +/* UART Component Parameter Register */ +#define LPSS_UART_CPR 0xF4 +#define LPSS_UART_CPR_AFCE BIT(4) + static void lpss_uart_setup(struct lpss_private_data *pdata) { unsigned int offset; - u32 reg; + u32 val; offset = pdata->dev_desc->prv_offset + LPSS_TX_INT; - reg = readl(pdata->mmio_base + offset); - writel(reg | LPSS_TX_INT_MASK, pdata->mmio_base + offset); + val = readl(pdata->mmio_base + offset); + writel(val | LPSS_TX_INT_MASK, pdata->mmio_base + offset); - offset = pdata->dev_desc->prv_offset + LPSS_GENERAL; - reg = readl(pdata->mmio_base + offset); - writel(reg | LPSS_GENERAL_UART_RTS_OVRD, pdata->mmio_base + offset); + val = readl(pdata->mmio_base + LPSS_UART_CPR); + if (!(val & LPSS_UART_CPR_AFCE)) { + offset = pdata->dev_desc->prv_offset + LPSS_GENERAL; + val = readl(pdata->mmio_base + offset); + val |= LPSS_GENERAL_UART_RTS_OVRD; + writel(val, pdata->mmio_base + offset); + } } static void byt_i2c_setup(struct lpss_private_data *pdata)