lkml.org 
[lkml]   [2015]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] pinctrl: cherryview: Configure HiZ pins to be input when requested as GPIOs
Date
If the pin is in HiZ mode when it is requested as GPIO its value cannot be
read (it always returns 0). In order to cope with the Linux GPIO subsystem
where we do not have such state at all, turn the pin to be input instead.

Reported-by: Jerome Blin <jerome.blin@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/pinctrl/intel/pinctrl-cherryview.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/intel/pinctrl-cherryview.c b/drivers/pinctrl/intel/pinctrl-cherryview.c
index dde67d425e9c..abe18960933d 100644
--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -880,9 +880,22 @@ static int chv_gpio_request_enable(struct pinctrl_dev *pctldev,
value &= ~CHV_PADCTRL1_INVRXTX_MASK;
chv_writel(value, reg);

- /* Switch to a GPIO mode */
reg = chv_padreg(pctrl, offset, CHV_PADCTRL0);
- value = readl(reg) | CHV_PADCTRL0_GPIOEN;
+ value = readl(reg);
+
+ /*
+ * If the pin is in HiZ mode (both TX and RX buffers are
+ * disabled) we turn it to be input now.
+ */
+ if ((value & CHV_PADCTRL0_GPIOCFG_MASK) ==
+ (CHV_PADCTRL0_GPIOCFG_HIZ << CHV_PADCTRL0_GPIOCFG_SHIFT)) {
+ value &= ~CHV_PADCTRL0_GPIOCFG_MASK;
+ value |= CHV_PADCTRL0_GPIOCFG_GPI <<
+ CHV_PADCTRL0_GPIOCFG_SHIFT;
+ }
+
+ /* Switch to a GPIO mode */
+ value |= CHV_PADCTRL0_GPIOEN;
chv_writel(value, reg);
}

--
2.1.4


\
 
 \ /
  Last update: 2015-01-29 12:01    [W:0.104 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site