pinctrl: imx: detect uninitialized pins

The pinctrl driver initialized the register offsets for the pins
with 0. On Vybrid an offset of 0 is a valid offset for the pinctrl
mux register. So far, this was solved using the ZERO_OFFSET_VALID
flag which allowed offsets of 0. However, this does not allow to
verify whether a pins struct imx_pmx_func was initialized or not.

Use signed offset values for register offsets and initialize those
with -1 in order to detect uninitialized offset values reliable.
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/freescale/pinctrl-imx.c

@@ -204,7 +204,7 @@ static int imx_pmx_set(struct pinctrl_dev *pctldev, unsigned selector,
 		pin_id = pin->pin;
 		pin_reg = &info->pin_regs[pin_id];
 
-		if (!(info->flags & ZERO_OFFSET_VALID) && !pin_reg->mux_reg) {
+		if (pin_reg->mux_reg == -1) {
 			dev_err(ipctl->dev, "Pin(%s) does not support mux function\n",
 				info->pins[pin_id].name);
 			return -EINVAL;
@@ -308,7 +308,7 @@ static int imx_pinconf_get(struct pinctrl_dev *pctldev,
 	const struct imx_pinctrl_soc_info *info = ipctl->info;
 	const struct imx_pin_reg *pin_reg = &info->pin_regs[pin_id];
 
-	if (!(info->flags & ZERO_OFFSET_VALID) && !pin_reg->conf_reg) {
+	if (pin_reg->conf_reg == -1) {
 		dev_err(info->dev, "Pin(%s) does not support config function\n",
 			info->pins[pin_id].name);
 		return -EINVAL;
@@ -331,7 +331,7 @@ static int imx_pinconf_set(struct pinctrl_dev *pctldev,
 	const struct imx_pin_reg *pin_reg = &info->pin_regs[pin_id];
 	int i;
 
-	if (!(info->flags & ZERO_OFFSET_VALID) && !pin_reg->conf_reg) {
+	if (pin_reg->conf_reg == -1) {
 		dev_err(info->dev, "Pin(%s) does not support config function\n",
 			info->pins[pin_id].name);
 		return -EINVAL;
@@ -586,10 +586,11 @@ int imx_pinctrl_probe(struct platform_device *pdev,
 	if (!ipctl)
 		return -ENOMEM;
 
-	info->pin_regs = devm_kzalloc(&pdev->dev, sizeof(*info->pin_regs) *
+	info->pin_regs = devm_kmalloc(&pdev->dev, sizeof(*info->pin_regs) *
 				      info->npins, GFP_KERNEL);
 	if (!info->pin_regs)
 		return -ENOMEM;
+	memset(info->pin_regs, 0xff, sizeof(*info->pin_regs) * info->npins);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	ipctl->base = devm_ioremap_resource(&pdev->dev, res);

drivers/pinctrl/freescale/pinctrl-imx.h

@@ -67,8 +67,8 @@ struct imx_pmx_func {
  * @conf_reg: config register offset
  */
 struct imx_pin_reg {
-	u16 mux_reg;
-	u16 conf_reg;
+	s16 mux_reg;
+	s16 conf_reg;
 };
 
 struct imx_pinctrl_soc_info {
@@ -83,8 +83,7 @@ struct imx_pinctrl_soc_info {
 	unsigned int flags;
 };
 
-#define ZERO_OFFSET_VALID	0x1
-#define SHARE_MUX_CONF_REG	0x2
+#define SHARE_MUX_CONF_REG	0x1
 
 #define NO_MUX		0x0
 #define NO_PAD		0x0

drivers/pinctrl/freescale/pinctrl-vf610.c

@@ -299,7 +299,7 @@ static const struct pinctrl_pin_desc vf610_pinctrl_pads[] = {
 static struct imx_pinctrl_soc_info vf610_pinctrl_info = {
 	.pins = vf610_pinctrl_pads,
 	.npins = ARRAY_SIZE(vf610_pinctrl_pads),
-	.flags = ZERO_OFFSET_VALID | SHARE_MUX_CONF_REG,
+	.flags = SHARE_MUX_CONF_REG,
 };
 
 static struct of_device_id vf610_pinctrl_of_match[] = {