gpio: stmpe: add verbose debug code
To troubleshoot the STMPE GPIO driver, some more detailed
debug information giving the exact info on how each pin is
used will be helpful.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 866baa8..85c5b19 100644
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -13,6 +13,7 @@
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/mfd/stmpe.h>
+#include <linux/seq_file.h>
/*
* These registers are modified under the irq bus lock and cached to avoid
@@ -211,6 +212,77 @@
stmpe_gpio->regs[REG_IE][regoffset] |= mask;
}
+static void stmpe_dbg_show_one(struct seq_file *s,
+ struct gpio_chip *gc,
+ unsigned offset, unsigned gpio)
+{
+ struct stmpe_gpio *stmpe_gpio = to_stmpe_gpio(gc);
+ struct stmpe *stmpe = stmpe_gpio->stmpe;
+ const char *label = gpiochip_is_requested(gc, offset);
+ int num_banks = DIV_ROUND_UP(stmpe->num_gpios, 8);
+ bool val = !!stmpe_gpio_get(gc, offset);
+ u8 dir_reg = stmpe->regs[STMPE_IDX_GPDR_LSB] - (offset / 8);
+ u8 mask = 1 << (offset % 8);
+ int ret;
+ u8 dir;
+
+ ret = stmpe_reg_read(stmpe, dir_reg);
+ if (ret < 0)
+ return;
+ dir = !!(ret & mask);
+
+ if (dir) {
+ seq_printf(s, " gpio-%-3d (%-20.20s) out %s",
+ gpio, label ?: "(none)",
+ val ? "hi" : "lo");
+ } else {
+ u8 edge_det_reg = stmpe->regs[STMPE_IDX_GPEDR_MSB] + num_banks - 1 - (offset / 8);
+ u8 rise_reg = stmpe->regs[STMPE_IDX_GPRER_LSB] - (offset / 8);
+ u8 fall_reg = stmpe->regs[STMPE_IDX_GPFER_LSB] - (offset / 8);
+ u8 irqen_reg = stmpe->regs[STMPE_IDX_IEGPIOR_LSB] - (offset / 8);
+ bool edge_det;
+ bool rise;
+ bool fall;
+ bool irqen;
+
+ ret = stmpe_reg_read(stmpe, edge_det_reg);
+ if (ret < 0)
+ return;
+ edge_det = !!(ret & mask);
+ ret = stmpe_reg_read(stmpe, rise_reg);
+ if (ret < 0)
+ return;
+ rise = !!(ret & mask);
+ ret = stmpe_reg_read(stmpe, fall_reg);
+ if (ret < 0)
+ return;
+ fall = !!(ret & mask);
+ ret = stmpe_reg_read(stmpe, irqen_reg);
+ if (ret < 0)
+ return;
+ irqen = !!(ret & mask);
+
+ seq_printf(s, " gpio-%-3d (%-20.20s) in %s %s %s%s%s",
+ gpio, label ?: "(none)",
+ val ? "hi" : "lo",
+ edge_det ? "edge-asserted" : "edge-inactive",
+ irqen ? "IRQ-enabled" : "",
+ rise ? " rising-edge-detection" : "",
+ fall ? " falling-edge-detection" : "");
+ }
+}
+
+static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
+{
+ unsigned i;
+ unsigned gpio = gc->base;
+
+ for (i = 0; i < gc->ngpio; i++, gpio++) {
+ stmpe_dbg_show_one(s, gc, i, gpio);
+ seq_printf(s, "\n");
+ }
+}
+
static struct irq_chip stmpe_gpio_irq_chip = {
.name = "stmpe-gpio",
.irq_bus_lock = stmpe_gpio_irq_lock,
@@ -293,6 +365,9 @@
#endif
stmpe_gpio->chip.base = -1;
+ if (IS_ENABLED(CONFIG_DEBUG_FS))
+ stmpe_gpio->chip.dbg_show = stmpe_dbg_show;
+
if (pdata)
stmpe_gpio->norequest_mask = pdata->norequest_mask;
else if (np)