[U-Boot] [PATCH 5/7] pinctrl: uniphier: support drive-strength configuration

[Masahiro Yamada <yamada.masahiro@socionext.com>]

This allows our DT to specify drive-strength property.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 drivers/pinctrl/uniphier/pinctrl-uniphier-core.c | 101 +++++++++++++++++++++++
 drivers/pinctrl/uniphier/pinctrl-uniphier.h      |  44 ++++++++--
 2 files changed, 140 insertions(+), 5 deletions(-)

diff --git a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
index 03103b3..39b5366 100644
--- a/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
+++ b/drivers/pinctrl/uniphier/pinctrl-uniphier-core.c
@@ -17,6 +17,9 @@
 
 #define UNIPHIER_PINCTRL_PINMUX_BASE	0x1000
 #define UNIPHIER_PINCTRL_LOAD_PINMUX	0x1700
+#define UNIPHIER_PINCTRL_DRVCTRL_BASE	0x1800
+#define UNIPHIER_PINCTRL_DRV2CTRL_BASE	0x1900
+#define UNIPHIER_PINCTRL_DRV3CTRL_BASE	0x1980
 #define UNIPHIER_PINCTRL_PUPDCTRL_BASE	0x1a00
 #define UNIPHIER_PINCTRL_IECTRL		0x1d00
 
@@ -142,10 +145,25 @@ static const struct pinconf_param uniphier_pinconf_params[] = {
 	{ "bias-pull-up", PIN_CONFIG_BIAS_PULL_UP, 1 },
 	{ "bias-pull-down", PIN_CONFIG_BIAS_PULL_DOWN, 1 },
 	{ "bias-pull-pin-default", PIN_CONFIG_BIAS_PULL_PIN_DEFAULT, 1 },
+	{ "drive-strength", PIN_CONFIG_DRIVE_STRENGTH, 0 },
 	{ "input-enable", PIN_CONFIG_INPUT_ENABLE, 1 },
 	{ "input-disable", PIN_CONFIG_INPUT_ENABLE, 0 },
 };
 
+static const struct uniphier_pinctrl_pin *
+uniphier_pinctrl_pin_get(struct uniphier_pinctrl_priv *priv, unsigned int pin)
+{
+	const struct uniphier_pinctrl_pin *pins = priv->socdata->pins;
+	int pins_count = priv->socdata->pins_count;
+	int i;
+
+	for (i = 0; i < pins_count; i++)
+		if (pins[i].number == pin)
+			return &pins[i];
+
+	return NULL;
+}
+
 static int uniphier_pinconf_bias_set(struct udevice *dev, unsigned int pin,
 				     unsigned int param, unsigned int arg)
 {
@@ -186,6 +204,86 @@ static int uniphier_pinconf_bias_set(struct udevice *dev, unsigned int pin,
 	return 0;
 }
 
+static const unsigned int uniphier_pinconf_drv_strengths_1bit[] = {
+	4, 8,
+};
+
+static const unsigned int uniphier_pinconf_drv_strengths_2bit[] = {
+	8, 12, 16, 20,
+};
+
+static const unsigned int uniphier_pinconf_drv_strengths_3bit[] = {
+	4, 5, 7, 9, 11, 12, 14, 16,
+};
+
+static int uniphier_pinconf_drive_set(struct udevice *dev, unsigned int pin,
+				      unsigned int strength)
+{
+	struct uniphier_pinctrl_priv *priv = dev_get_priv(dev);
+	const struct uniphier_pinctrl_pin *desc;
+	const unsigned int *strengths;
+	unsigned int base, stride, width, drvctrl, reg, shift;
+	u32 val, mask, tmp;
+
+	desc = uniphier_pinctrl_pin_get(priv, pin);
+	if (WARN_ON(!desc))
+		return -EINVAL;
+
+	switch (uniphier_pin_get_drv_type(desc->data)) {
+	case UNIPHIER_PIN_DRV_1BIT:
+		strengths = uniphier_pinconf_drv_strengths_1bit;
+		base = UNIPHIER_PINCTRL_DRVCTRL_BASE;
+		stride = 1;
+		width = 1;
+		break;
+	case UNIPHIER_PIN_DRV_2BIT:
+		strengths = uniphier_pinconf_drv_strengths_2bit;
+		base = UNIPHIER_PINCTRL_DRV2CTRL_BASE;
+		stride = 2;
+		width = 2;
+		break;
+	case UNIPHIER_PIN_DRV_3BIT:
+		strengths = uniphier_pinconf_drv_strengths_3bit;
+		base = UNIPHIER_PINCTRL_DRV3CTRL_BASE;
+		stride = 4;
+		width = 3;
+		break;
+	default:
+		/* drive strength control is not supported for this pin */
+		return -EINVAL;
+	}
+
+	drvctrl = uniphier_pin_get_drvctrl(desc->data);
+	drvctrl *= stride;
+
+	reg = base + drvctrl / 32 * 4;
+	shift = drvctrl % 32;
+	mask = (1U << width) - 1;
+
+	for (val = 0; val <= mask; val++) {
+		if (strengths[val] > strength)
+			break;
+	}
+
+	if (val == 0) {
+		dev_err(dev, "unsupported drive strength %u mA for pin %s\n",
+			strength, desc->name);
+		return -EINVAL;
+	}
+
+	if (!mask)
+		return 0;
+
+	val--;
+
+	tmp = readl(priv->base + reg);
+	tmp &= ~(mask << shift);
+	tmp |= (mask & val) << shift;
+	writel(tmp, priv->base + reg);
+
+	return 0;
+}
+
 static int uniphier_pinconf_set(struct udevice *dev, unsigned int pin,
 				unsigned int param, unsigned int arg)
 {
@@ -198,6 +296,9 @@ static int uniphier_pinconf_set(struct udevice *dev, unsigned int pin,
 	case PIN_CONFIG_BIAS_PULL_PIN_DEFAULT:
 		ret = uniphier_pinconf_bias_set(dev, pin, param, arg);
 		break;
+	case PIN_CONFIG_DRIVE_STRENGTH:
+		ret = uniphier_pinconf_drive_set(dev, pin, arg);
+		break;
 	case PIN_CONFIG_INPUT_ENABLE:
 		ret = uniphier_pinconf_input_enable(dev, pin, arg);
 		break;
diff --git a/drivers/pinctrl/uniphier/pinctrl-uniphier.h b/drivers/pinctrl/uniphier/pinctrl-uniphier.h
index 8884b08..3f47693 100644
--- a/drivers/pinctrl/uniphier/pinctrl-uniphier.h
+++ b/drivers/pinctrl/uniphier/pinctrl-uniphier.h
@@ -13,11 +13,44 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 
-#define UNIPHIER_PIN_ATTR_PACKED(iectrl)	(iectrl)
+/* drive strength control register number */
+#define UNIPHIER_PIN_DRVCTRL_SHIFT	0
+#define UNIPHIER_PIN_DRVCTRL_BITS	9
+#define UNIPHIER_PIN_DRVCTRL_MASK	((1U << (UNIPHIER_PIN_DRVCTRL_BITS)) \
+					 - 1)
+
+/* drive control type */
+#define UNIPHIER_PIN_DRV_TYPE_SHIFT	((UNIPHIER_PIN_DRVCTRL_SHIFT) + \
+					 (UNIPHIER_PIN_DRVCTRL_BITS))
+#define UNIPHIER_PIN_DRV_TYPE_BITS	2
+#define UNIPHIER_PIN_DRV_TYPE_MASK	((1U << (UNIPHIER_PIN_DRV_TYPE_BITS)) \
+					 - 1)
+
+/* drive control type */
+enum uniphier_pin_drv_type {
+	UNIPHIER_PIN_DRV_1BIT,		/* 2 level control: 4/8 mA */
+	UNIPHIER_PIN_DRV_2BIT,		/* 4 level control: 8/12/16/20 mA */
+	UNIPHIER_PIN_DRV_3BIT,		/* 8 level control: 4/5/7/9/11/12/14/16 mA */
+};
+
+#define UNIPHIER_PIN_DRVCTRL(x) \
+	(((x) & (UNIPHIER_PIN_DRVCTRL_MASK)) << (UNIPHIER_PIN_DRVCTRL_SHIFT))
+#define UNIPHIER_PIN_DRV_TYPE(x) \
+	(((x) & (UNIPHIER_PIN_DRV_TYPE_MASK)) << (UNIPHIER_PIN_DRV_TYPE_SHIFT))
+
+#define UNIPHIER_PIN_ATTR_PACKED(drvctrl, drv_type)	\
+	UNIPHIER_PIN_DRVCTRL(drvctrl) |			\
+	UNIPHIER_PIN_DRV_TYPE(drv_type)
+
+static inline unsigned int uniphier_pin_get_drvctrl(unsigned int data)
+{
+	return (data >> UNIPHIER_PIN_DRVCTRL_SHIFT) & UNIPHIER_PIN_DRVCTRL_MASK;
+}
 
-static inline unsigned int uniphier_pin_get_iectrl(unsigned long data)
+static inline unsigned int uniphier_pin_get_drv_type(unsigned int data)
 {
-	return data;
+	return (data >> UNIPHIER_PIN_DRV_TYPE_SHIFT) &
+						UNIPHIER_PIN_DRV_TYPE_MASK;
 }
 
 /**
@@ -74,10 +107,11 @@ struct uniphier_pinctrl_socdata {
 #define UNIPHIER_PINCTRL_CAPS_MUX_4BIT		BIT(0)
 };
 
-#define UNIPHIER_PINCTRL_PIN(a, b)					\
+#define UNIPHIER_PINCTRL_PIN(a, b, c, d)				\
 {									\
 	.number = a,							\
-	.data = UNIPHIER_PIN_ATTR_PACKED(b),				\
+	.name = b,							\
+	.data = UNIPHIER_PIN_ATTR_PACKED(c, d),				\
 }
 
 #define __UNIPHIER_PINCTRL_GROUP(grp)					\
-- 
2.7.4