pinctrl: bcm2835: Add support for BCM2711 pull-up functionality

The BCM2711 has a new way of selecting the pull-up/pull-down setting
for a GPIO pin. The registers used for the BCM2835, GP_PUD and
GP_PUDCLKn0, are no longer connected. A new set of registers,
GP_GPIO_PUP_PDN_CNTRL_REGx must be used. This commit will add
a new compatible string "brcm,bcm2711-gpio" and the kernel
driver will use it to select which method is used to select
pull-up/pull-down.

This patch based on a patch by Al Cooper which was intended for the
BCM7211. This is a bugfixed and improved version.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/1563776607-8368-3-git-send-email-wahrenst@gmx.net
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 100 insertions, 5 deletions

diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index 183d1ffe6a75..a493205bedaf 100644
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
@@ -57,15 +57,24 @@
 #define GPAFEN0		0x88	/* Pin Async Falling Edge Detect */
 #define GPPUD		0x94	/* Pin Pull-up/down Enable */
 #define GPPUDCLK0	0x98	/* Pin Pull-up/down Enable Clock */
+#define GP_GPIO_PUP_PDN_CNTRL_REG0 0xe4 /* 2711 Pin Pull-up/down select */
 
 #define FSEL_REG(p)		(GPFSEL0 + (((p) / 10) * 4))
 #define FSEL_SHIFT(p)		(((p) % 10) * 3)
 #define GPIO_REG_OFFSET(p)	((p) / 32)
 #define GPIO_REG_SHIFT(p)	((p) % 32)
 
+#define PUD_2711_MASK		0x3
+#define PUD_2711_REG_OFFSET(p)	((p) / 16)
+#define PUD_2711_REG_SHIFT(p)	(((p) % 16) * 2)
+
 /* argument: bcm2835_pinconf_pull */
 #define BCM2835_PINCONF_PARAM_PULL	(PIN_CONFIG_END + 1)
 
+#define BCM2711_PULL_NONE	0x0
+#define BCM2711_PULL_UP		0x1
+#define BCM2711_PULL_DOWN	0x2
+
 struct bcm2835_pinctrl {
 	struct device *dev;
 	void __iomem *base;
@@ -975,6 +984,77 @@ static const struct pinconf_ops bcm2835_pinconf_ops = {
 	.pin_config_set = bcm2835_pinconf_set,
 };
 
+static void bcm2711_pull_config_set(struct bcm2835_pinctrl *pc,
+				    unsigned int pin, unsigned int arg)
+{
+	u32 shifter;
+	u32 value;
+	u32 off;
+
+	off = PUD_2711_REG_OFFSET(pin);
+	shifter = PUD_2711_REG_SHIFT(pin);
+
+	value = bcm2835_gpio_rd(pc, GP_GPIO_PUP_PDN_CNTRL_REG0 + (off * 4));
+	value &= ~(PUD_2711_MASK << shifter);
+	value |= (arg << shifter);
+	bcm2835_gpio_wr(pc, GP_GPIO_PUP_PDN_CNTRL_REG0 + (off * 4), value);
+}
+
+static int bcm2711_pinconf_set(struct pinctrl_dev *pctldev,
+			       unsigned int pin, unsigned long *configs,
+			       unsigned int num_configs)
+{
+	struct bcm2835_pinctrl *pc = pinctrl_dev_get_drvdata(pctldev);
+	u32 param, arg;
+	int i;
+
+	for (i = 0; i < num_configs; i++) {
+		param = pinconf_to_config_param(configs[i]);
+		arg = pinconf_to_config_argument(configs[i]);
+
+		switch (param) {
+		/* convert legacy brcm,pull */
+		case BCM2835_PINCONF_PARAM_PULL:
+			if (arg == BCM2835_PUD_UP)
+				arg = BCM2711_PULL_UP;
+			else if (arg == BCM2835_PUD_DOWN)
+				arg = BCM2711_PULL_DOWN;
+			else
+				arg = BCM2711_PULL_NONE;
+
+			bcm2711_pull_config_set(pc, pin, arg);
+			break;
+
+		/* Set pull generic bindings */
+		case PIN_CONFIG_BIAS_DISABLE:
+			bcm2711_pull_config_set(pc, pin, BCM2711_PULL_NONE);
+			break;
+		case PIN_CONFIG_BIAS_PULL_DOWN:
+			bcm2711_pull_config_set(pc, pin, BCM2711_PULL_DOWN);
+			break;
+		case PIN_CONFIG_BIAS_PULL_UP:
+			bcm2711_pull_config_set(pc, pin, BCM2711_PULL_UP);
+			break;
+
+		/* Set output-high or output-low */
+		case PIN_CONFIG_OUTPUT:
+			bcm2835_gpio_set_bit(pc, arg ? GPSET0 : GPCLR0, pin);
+			break;
+
+		default:
+			return -ENOTSUPP;
+		}
+	} /* for each config */
+
+	return 0;
+}
+
+static const struct pinconf_ops bcm2711_pinconf_ops = {
+	.is_generic = true,
+	.pin_config_get = bcm2835_pinconf_get,
+	.pin_config_set = bcm2711_pinconf_set,
+};
+
 static struct pinctrl_desc bcm2835_pinctrl_desc = {
 	.name = MODULE_NAME,
 	.pins = bcm2835_gpio_pins,
@@ -990,6 +1070,18 @@ static struct pinctrl_gpio_range bcm2835_pinctrl_gpio_range = {
 	.npins = BCM2835_NUM_GPIOS,
 };
 
+static const struct of_device_id bcm2835_pinctrl_match[] = {
+	{
+		.compatible = "brcm,bcm2835-gpio",
+		.data = &bcm2835_pinconf_ops,
+	},
+	{
+		.compatible = "brcm,bcm2711-gpio",
+		.data = &bcm2711_pinconf_ops,
+	},
+	{}
+};
+
 static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -997,6 +1089,8 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	struct bcm2835_pinctrl *pc;
 	struct resource iomem;
 	int err, i;
+	const struct of_device_id *match;
+
 	BUILD_BUG_ON(ARRAY_SIZE(bcm2835_gpio_pins) != BCM2835_NUM_GPIOS);
 	BUILD_BUG_ON(ARRAY_SIZE(bcm2835_gpio_groups) != BCM2835_NUM_GPIOS);
 
@@ -1073,6 +1167,12 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 					     bcm2835_gpio_irq_handler);
 	}
 
+	match = of_match_node(bcm2835_pinctrl_match, pdev->dev.of_node);
+	if (match) {
+		bcm2835_pinctrl_desc.confops =
+			(const struct pinconf_ops *)match->data;
+	}
+
 	pc->pctl_dev = devm_pinctrl_register(dev, &bcm2835_pinctrl_desc, pc);
 	if (IS_ERR(pc->pctl_dev)) {
 		gpiochip_remove(&pc->gpio_chip);
@@ -1087,11 +1187,6 @@ static int bcm2835_pinctrl_probe(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct of_device_id bcm2835_pinctrl_match[] = {
-	{ .compatible = "brcm,bcm2835-gpio" },
-	{}
-};
-
 static struct platform_driver bcm2835_pinctrl_driver = {
 	.probe = bcm2835_pinctrl_probe,
 	.driver = {