pinctrl: qcom: Add egpio feature support

egpio is a scheme which allows special power Island Domain IOs
(LPASS,SSC) to be reused as regular chip GPIOs by muxing regular
TLMM functions with Island Domain functions.
With this scheme, an IO can be controlled both by the cpu running
linux and the Island processor. This provides great flexibility to
re-purpose the Island IOs for regular TLMM usecases.

2 new bits are added to ctl_reg, egpio_present is a read only bit
which shows if egpio feature is available or not on a given gpio.
egpio_enable is the read/write bit and only effective if egpio_present
is 1. Once its set, the Island IO is controlled from Chip TLMM.
egpio_enable when set to 0 means the GPIO is used as Island Domain IO.

To support this we add a new function 'egpio' which can be used to
set the egpio_enable to 0, for any other TLMM controlled functions
we set the egpio_enable to 1.

Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Link: https://lore.kernel.org/r/1637041084-3299-1-git-send-email-rnayak@codeaurora.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index 8476a8ac4451..ae09e2dd8a50 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -185,6 +185,7 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev,
 	unsigned int irq = irq_find_mapping(gc->irq.domain, group);
 	struct irq_data *d = irq_get_irq_data(irq);
 	unsigned int gpio_func = pctrl->soc->gpio_func;
+	unsigned int egpio_func = pctrl->soc->egpio_func;
 	const struct msm_pingroup *g;
 	unsigned long flags;
 	u32 val, mask;
@@ -218,8 +219,18 @@ static int msm_pinmux_set_mux(struct pinctrl_dev *pctldev,
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
 
 	val = msm_readl_ctl(pctrl, g);
-	val &= ~mask;
-	val |= i << g->mux_bit;
+
+	if (egpio_func && i == egpio_func) {
+		if (val & BIT(g->egpio_present))
+			val &= ~BIT(g->egpio_enable);
+	} else {
+		val &= ~mask;
+		val |= i << g->mux_bit;
+		/* Claim ownership of pin if egpio capable */
+		if (egpio_func && val & BIT(g->egpio_present))
+			val |= BIT(g->egpio_enable);
+	}
+
 	msm_writel_ctl(val, pctrl, g);
 
 	raw_spin_unlock_irqrestore(&pctrl->lock, flags);