Subject: [PATCH net-next v2 2/2] net: dsa: mt7530: MT7530 optional GPIO support

From: DENG Qingfang <[email-masked]>
Date: Mon, 25 Jan 2021 12:43:22 +0800

MT7530's LED controller can drive up to 15 LED/GPIOs.

Add support for GPIO control and allow users to use its GPIOs by
setting gpio-controller property in device tree.

Signed-off-by: DENG Qingfang <[email-masked]>
---
Changes v1 -> v2:

Set Output Enable after changing direction to output to avoid signal
glitch.
Comment mt7530_gpio_to_bit function.

 drivers/net/dsa/mt7530.c | 110 +++++++++++++++++++++++++++++++++++++++
 drivers/net/dsa/mt7530.h |  20 +++++++
 2 files changed, 130 insertions(+)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index d2196197d920..eb13ba79dd01 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -18,6 +18,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 #include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
 #include <net/dsa.h>
 
 #include "mt7530.h"
@@ -1622,6 +1623,109 @@ mtk_get_tag_protocol(struct dsa_switch *ds, int port,
 	}
 }
 
+static inline u32
+mt7530_gpio_to_bit(unsigned int offset)
+{
+	/* Map GPIO offset to register bit
+	 * [ 2: 0]  port 0 LED 0..2 as GPIO 0..2
+	 * [ 6: 4]  port 1 LED 0..2 as GPIO 3..5
+	 * [10: 8]  port 2 LED 0..2 as GPIO 6..8
+	 * [14:12]  port 3 LED 0..2 as GPIO 9..11
+	 * [18:16]  port 4 LED 0..2 as GPIO 12..14
+	 */
+	return BIT(offset + offset / 3);
+}
+
+static int
+mt7530_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct mt7530_priv *priv = gpiochip_get_data(gc);
+	u32 bit = mt7530_gpio_to_bit(offset);
+
+	return !!(mt7530_read(priv, MT7530_LED_GPIO_DATA) & bit);
+}
+
+static void
+mt7530_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
+{
+	struct mt7530_priv *priv = gpiochip_get_data(gc);
+	u32 bit = mt7530_gpio_to_bit(offset);
+
+	if (value)
+		mt7530_set(priv, MT7530_LED_GPIO_DATA, bit);
+	else
+		mt7530_clear(priv, MT7530_LED_GPIO_DATA, bit);
+}
+
+static int
+mt7530_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	struct mt7530_priv *priv = gpiochip_get_data(gc);
+	u32 bit = mt7530_gpio_to_bit(offset);
+
+	return (mt7530_read(priv, MT7530_LED_GPIO_DIR) & bit) ?
+		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int
+mt7530_gpio_direction_input(struct gpio_chip *gc, unsigned int offset)
+{
+	struct mt7530_priv *priv = gpiochip_get_data(gc);
+	u32 bit = mt7530_gpio_to_bit(offset);
+
+	mt7530_clear(priv, MT7530_LED_GPIO_OE, bit);
+	mt7530_clear(priv, MT7530_LED_GPIO_DIR, bit);
+
+	return 0;
+}
+
+static int
+mt7530_gpio_direction_output(struct gpio_chip *gc, unsigned int offset, int value)
+{
+	struct mt7530_priv *priv = gpiochip_get_data(gc);
+	u32 bit = mt7530_gpio_to_bit(offset);
+
+	mt7530_set(priv, MT7530_LED_GPIO_DIR, bit);
+
+	if (value)
+		mt7530_set(priv, MT7530_LED_GPIO_DATA, bit);
+	else
+		mt7530_clear(priv, MT7530_LED_GPIO_DATA, bit);
+
+	mt7530_set(priv, MT7530_LED_GPIO_OE, bit);
+
+	return 0;
+}
+
+static int
+mt7530_setup_gpio(struct mt7530_priv *priv)
+{
+	struct device *dev = priv->dev;
+	struct gpio_chip *gc;
+
+	gc = devm_kzalloc(dev, sizeof(*gc), GFP_KERNEL);
+	if (!gc)
+		return -ENOMEM;
+
+	mt7530_write(priv, MT7530_LED_GPIO_OE, 0);
+	mt7530_write(priv, MT7530_LED_GPIO_DIR, 0);
+	mt7530_write(priv, MT7530_LED_IO_MODE, 0);
+
+	gc->label = "mt7530";
+	gc->parent = dev;
+	gc->owner = THIS_MODULE;
+	gc->get_direction = mt7530_gpio_get_direction;
+	gc->direction_input = mt7530_gpio_direction_input;
+	gc->direction_output = mt7530_gpio_direction_output;
+	gc->get = mt7530_gpio_get;
+	gc->set = mt7530_gpio_set;
+	gc->base = -1;
+	gc->ngpio = 15;
+	gc->can_sleep = true;
+
+	return devm_gpiochip_add_data(dev, gc, priv);
+}
+
 static int
 mt7530_setup(struct dsa_switch *ds)
 {
@@ -1763,6 +1867,12 @@ mt7530_setup(struct dsa_switch *ds)
 		}
 	}
 
+	if (of_property_read_bool(priv->dev->of_node, "gpio-controller")) {
+		ret = mt7530_setup_gpio(priv);
+		if (ret)
+			return ret;
+	}
+
 	mt7530_setup_port5(ds, interface);
 
 	/* Flush the FDB table */
diff --git a/drivers/net/dsa/mt7530.h b/drivers/net/dsa/mt7530.h
index 32d8969b3ace..64a9bb377e15 100644
--- a/drivers/net/dsa/mt7530.h
+++ b/drivers/net/dsa/mt7530.h
@@ -554,6 +554,26 @@ enum mt7531_clk_skew {
 #define  MT7531_GPIO12_RG_RXD3_MASK	GENMASK(19, 16)
 #define  MT7531_EXT_P_MDIO_12		(2 << 16)
 
+/* Registers for LED GPIO control (MT7530 only)
+ * All registers follow this pattern:
+ * [ 2: 0]  port 0
+ * [ 6: 4]  port 1
+ * [10: 8]  port 2
+ * [14:12]  port 3
+ * [18:16]  port 4
+ */
+
+/* LED enable, 0: Disable, 1: Enable (Default) */
+#define MT7530_LED_EN			0x7d00
+/* LED mode, 0: GPIO mode, 1: PHY mode (Default) */
+#define MT7530_LED_IO_MODE		0x7d04
+/* GPIO direction, 0: Input, 1: Output */
+#define MT7530_LED_GPIO_DIR		0x7d10
+/* GPIO output enable, 0: Disable, 1: Enable */
+#define MT7530_LED_GPIO_OE		0x7d14
+/* GPIO value, 0: Low, 1: High */
+#define MT7530_LED_GPIO_DATA		0x7d18
+
 #define MT7530_CREV			0x7ffc
 #define  CHIP_NAME_SHIFT		16
 #define  MT7530_ID			0x7530
-- 
2.25.1