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authorLee Jones <lee.jones@linaro.org>2015-03-18 20:21:17 +0300
committerLinus Walleij <linus.walleij@linaro.org>2015-03-25 18:37:03 +0300
commit1e702ec2aa3bfed17d1266d31f94923322afbc60 (patch)
treed8f19c9482ca5971ab1c24d0c9ad6c5216c94a29 /drivers/pinctrl/pinctrl-st.c
parentf89e68fc3b5a5d53d73a0df71b94d3c0a009d0ba (diff)
downloadlinux-1e702ec2aa3bfed17d1266d31f94923322afbc60.tar.xz
pinctrl: st: Supply a GPIO get_direction() call-back
ST's hardware differentiates between GPIO mode and Pinctrl alternate functions. When a pin is in GPIO mode, there are dedicated registers to set and obtain direction status. However, If a pin's alternate function is in use then the direction is set and status is derived from a bunch of syscon registers. The issue is; until now there was a lack of parity between the two. For example: Catting the two following information sources could result in conflicting information (output has been snipped for simplicity): $ cat /sys/kernel/debug/gpio GPIOs 32-39, platform/961f080.pin-controller-sbc, PIO4: gpio-33 (? ) out hi $ cat /sys/kernel/debug/pinctrl/<pin-controller>/pinconf-pins pin 33 (PIO4[1]):[OE:0,PU:0,OD:0] [retime:0,invclk:0,clknotdat:0,de:0,rt-clk:0,rt-delay:0] In this example GPIO-33 is a GPIO controlled LED, which is set for output, as you'd expect. However, when the same information is drafted from Pinctrl, it clearly states that OE (Output Enable) is not set i.e. the pin is set for input. This is because OE normally only represents alternate functions and has no bearing on how the pin operates when in Alt-0 (GPIO mode). This patch changes the current semantics and provides a parity link between the two subsystems. The get_direction() call-back firstly determines which function a pin is operating in, then uses the appropriate helpers for that mode. Reported-by: Olivier Clergeaud <olivier.clergeaud@st.com> Acked-by: Maxime Coquelin <maxime.coquelin@st.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl/pinctrl-st.c')
-rw-r--r--drivers/pinctrl/pinctrl-st.c31
1 files changed, 30 insertions, 1 deletions
diff --git a/drivers/pinctrl/pinctrl-st.c b/drivers/pinctrl/pinctrl-st.c
index 10ad19c73900..52a437738cc2 100644
--- a/drivers/pinctrl/pinctrl-st.c
+++ b/drivers/pinctrl/pinctrl-st.c
@@ -206,7 +206,6 @@
#define gpio_chip_to_bank(chip) \
container_of(chip, struct st_gpio_bank, gpio_chip)
-
enum st_retime_style {
st_retime_style_none,
st_retime_style_packed,
@@ -781,6 +780,35 @@ static int st_gpio_direction_output(struct gpio_chip *chip,
return 0;
}
+static int st_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+ struct st_gpio_bank *bank = gpio_chip_to_bank(chip);
+ struct st_pio_control pc = bank->pc;
+ unsigned long config;
+ unsigned int direction = 0;
+ unsigned int function;
+ unsigned int value;
+ int i = 0;
+
+ /* Alternate function direction is handled by Pinctrl */
+ function = st_pctl_get_pin_function(&pc, offset);
+ if (function) {
+ st_pinconf_get_direction(&pc, offset, &config);
+ return !ST_PINCONF_UNPACK_OE(config);
+ }
+
+ /*
+ * GPIO direction is handled differently
+ * - See st_gpio_direction() above for an explanation
+ */
+ for (i = 0; i <= 2; i++) {
+ value = readl(bank->base + REG_PIO_PC(i));
+ direction |= ((value >> offset) & 0x1) << i;
+ }
+
+ return (direction == ST_GPIO_DIRECTION_IN);
+}
+
static int st_gpio_xlate(struct gpio_chip *gc,
const struct of_phandle_args *gpiospec, u32 *flags)
{
@@ -1452,6 +1480,7 @@ static struct gpio_chip st_gpio_template = {
.set = st_gpio_set,
.direction_input = st_gpio_direction_input,
.direction_output = st_gpio_direction_output,
+ .get_direction = st_gpio_get_direction,
.ngpio = ST_GPIO_PINS_PER_BANK,
.of_gpio_n_cells = 1,
.of_xlate = st_gpio_xlate,