[PATCH 1/2] [v4] pinctrl: qcom: disable GPIO groups with no pins

[Timur Tabi]

pinctrl-msm only accepts an array of GPIOs from 0 to n-1, and it expects
each group to support have only one pin (npins == 1).

We can support "sparse" GPIO maps if allow for some groups to have zero
pins (npins == 0).  These pins are "hidden" from the rest of the driver
and gpiolib.

A new boolean 'sparse' indicates whether the GPIO maps is sparse.  If any
GPIO has an 'npins' value of 0, then 'sparse' must be set to True.

Signed-off-by: Timur Tabi <timur at codeaurora.org>
---
 drivers/pinctrl/qcom/pinctrl-msm.c | 36 +++++++++++++++++++++++++++++++-----
 drivers/pinctrl/qcom/pinctrl-msm.h |  2 ++
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/pinctrl/qcom/pinctrl-msm.c b/drivers/pinctrl/qcom/pinctrl-msm.c
index ff491da64dab..75d70c65766d 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.c
+++ b/drivers/pinctrl/qcom/pinctrl-msm.c
@@ -507,6 +507,11 @@ static void msm_gpio_dbg_show_one(struct seq_file *s,
 	};
 
 	g = &pctrl->soc->groups[offset];
+
+	/* If the GPIO group has no pins, then don't show it. */
+	if (!g->npins)
+		return;
+
 	ctl_reg = readl(pctrl->regs + g->ctl_reg);
 
 	is_out = !!(ctl_reg & BIT(g->oe_bit));
@@ -516,7 +521,7 @@ static void msm_gpio_dbg_show_one(struct seq_file *s,
 
 	seq_printf(s, " %-8s: %-3s %d", g->name, is_out ? "out" : "in", func);
 	seq_printf(s, " %dmA", msm_regval_to_drive(drive));
-	seq_printf(s, " %s", pulls[pull]);
+	seq_printf(s, " %s\n", pulls[pull]);
 }
 
 static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
@@ -524,23 +529,30 @@ static void msm_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	unsigned gpio = chip->base;
 	unsigned i;
 
-	for (i = 0; i < chip->ngpio; i++, gpio++) {
+	for (i = 0; i < chip->ngpio; i++, gpio++)
 		msm_gpio_dbg_show_one(s, NULL, chip, i, gpio);
-		seq_puts(s, "\n");
-	}
 }
 
 #else
 #define msm_gpio_dbg_show NULL
 #endif
 
+/* If the GPIO has no pins, then treat it as unavailable. */
+static int msm_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	struct msm_pinctrl *pctrl = gpiochip_get_data(chip);
+	const struct msm_pingroup *g = &pctrl->soc->groups[offset];
+
+	return g->npins ? 0 : -ENODEV;
+}
+
 static const struct gpio_chip msm_gpio_template = {
 	.direction_input  = msm_gpio_direction_input,
 	.direction_output = msm_gpio_direction_output,
 	.get_direction    = msm_gpio_get_direction,
 	.get              = msm_gpio_get,
 	.set              = msm_gpio_set,
-	.request          = gpiochip_generic_request,
+	.request          = msm_gpio_request,
 	.free             = gpiochip_generic_free,
 	.dbg_show         = msm_gpio_dbg_show,
 };
@@ -813,6 +825,7 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	struct gpio_chip *chip;
 	int ret;
 	unsigned ngpio = pctrl->soc->ngpios;
+	unsigned int i;
 
 	if (WARN_ON(ngpio > MAX_NR_GPIO))
 		return -EINVAL;
@@ -825,12 +838,25 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 	chip->owner = THIS_MODULE;
 	chip->of_node = pctrl->dev->of_node;
 
+	/* If the GPIO map is sparse, then we need to disable specific IRQs */
+	chip->irq_need_valid_mask = pctrl->soc->sparse;
+
 	ret = gpiochip_add_data(&pctrl->chip, pctrl);
 	if (ret) {
 		dev_err(pctrl->dev, "Failed register gpiochip\n");
 		return ret;
 	}
 
+	/*
+	 * If irq_need_valid_mask is true, then gpiochip_add_data() will
+	 * initialize irq_valid_mask to all 1s. We need to clear all the
+	 * GPIOs that are unavailable.
+	 */
+	if (chip->irq_need_valid_mask)
+		for (i = 0; i < ngpio; i++)
+			if (!pctrl->soc->groups[i].npins)
+				clear_bit(i, pctrl->chip.irq_valid_mask);
+
 	ret = gpiochip_add_pin_range(&pctrl->chip, dev_name(pctrl->dev), 0, 0, chip->ngpio);
 	if (ret) {
 		dev_err(pctrl->dev, "Failed to add pin range\n");
diff --git a/drivers/pinctrl/qcom/pinctrl-msm.h b/drivers/pinctrl/qcom/pinctrl-msm.h
index 9b9feea540ff..70762bcb84cb 100644
--- a/drivers/pinctrl/qcom/pinctrl-msm.h
+++ b/drivers/pinctrl/qcom/pinctrl-msm.h
@@ -107,6 +107,7 @@ struct msm_pingroup {
  * @ngroups:	    The numbmer of entries in @groups.
  * @ngpio:	    The number of pingroups the driver should expose as GPIOs.
  * @pull_no_keeper: The SoC does not support keeper bias.
+ * @sparse:         The GPIO map is sparse (some GPIOs have npins == 0)
  */
 struct msm_pinctrl_soc_data {
 	const struct pinctrl_pin_desc *pins;
@@ -117,6 +118,7 @@ struct msm_pinctrl_soc_data {
 	unsigned ngroups;
 	unsigned ngpios;
 	bool pull_no_keeper;
+	bool sparse;
 };
 
 int msm_pinctrl_probe(struct platform_device *pdev,
-- 
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Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.