From 1f47a77c4e4951f141bf20fe7f7c5d9438ea1663 Mon Sep 17 00:00:00 2001 From: Heikki Krogerus Date: Thu, 11 Sep 2014 15:19:33 +0300 Subject: ACPI / LPSS: not using UART RTS override with Auto Flow Control Adding a check for UART Auto Flow Control feature and only enabling the RTS override when it's not supported. RTS override is not needed when Auto Flow Control is used and they shouldn't be used together. Signed-off-by: Heikki Krogerus Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpi_lpss.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) (limited to 'drivers/acpi') 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); - - 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 + offset); + writel(val | LPSS_TX_INT_MASK, 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) -- cgit v1.2.3