linux-kernel - [PATCH 3/3] gpio: syscon: Add support for the Xylon LogiCVC GPIOs

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Date:   Tue, 10 Sep 2019 17:28:55 +0200
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Subject: [PATCH 3/3] gpio: syscon: Add support for the Xylon LogiCVC GPIOs

The LogiCVC display hardware block comes with GPIO capabilities
that must be exposed separately from the main driver (as GPIOs) for
use with regulators and panels. A syscon is used to share the same
regmap across the two drivers.

Since the GPIO capabilities are pretty simple, add them to the syscon
GPIO driver.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
---
 drivers/gpio/gpio-syscon.c | 68 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/drivers/gpio/gpio-syscon.c b/drivers/gpio/gpio-syscon.c
index 05c537ed73f1..3d435187940b 100644
--- a/drivers/gpio/gpio-syscon.c
+++ b/drivers/gpio/gpio-syscon.c
@@ -190,6 +190,70 @@ static const struct syscon_gpio_data keystone_dsp_gpio = {
 	.set		= keystone_gpio_set,
 };
 
+#define LOGICVC_CTRL_REG		0x40
+#define LOGICVC_CTRL_GPIO_SHIFT		11
+#define LOGICVC_CTRL_GPIO_BITS		5
+
+#define LOGICVC_POWER_CTRL_REG		0x78
+#define LOGICVC_POWER_CTRL_GPIO_SHIFT	0
+#define LOGICVC_POWER_CTRL_GPIO_BITS	4
+
+static void logicvc_gpio_offset(struct syscon_gpio_priv *priv,
+				unsigned offset, unsigned int *reg,
+				unsigned int *bit)
+{
+	if (offset >= LOGICVC_CTRL_GPIO_BITS) {
+		*reg = LOGICVC_POWER_CTRL_REG;
+
+		/* To the (virtual) power ctrl offset. */
+		offset -= LOGICVC_CTRL_GPIO_BITS;
+		/* To the actual bit offset in reg. */
+		offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
+	} else {
+		*reg = LOGICVC_CTRL_REG;
+
+		/* To the actual bit offset in reg. */
+		offset += LOGICVC_CTRL_GPIO_SHIFT;
+	}
+
+	*bit = 1 << offset;
+}
+
+static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
+	unsigned int reg;
+	unsigned int bit;
+	unsigned int value;
+	int ret;
+
+	logicvc_gpio_offset(priv, offset, &reg, &bit);
+
+	ret = regmap_read(priv->syscon, reg, &value);
+	if (ret)
+		return ret;
+
+	return !!(value & bit);
+}
+
+static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
+{
+	struct syscon_gpio_priv *priv = gpiochip_get_data(chip);
+	unsigned int reg;
+	unsigned int bit;
+
+	logicvc_gpio_offset(priv, offset, &reg, &bit);
+
+	regmap_update_bits(priv->syscon, reg, bit, val ? bit : 0);
+}
+
+static const struct syscon_gpio_data logicvc_3_gpio = {
+	.flags		= GPIO_SYSCON_FEAT_OUT,
+	.bit_count	= LOGICVC_CTRL_GPIO_BITS + LOGICVC_POWER_CTRL_GPIO_BITS,
+	.get		= logicvc_gpio_get,
+	.set		= logicvc_gpio_set,
+};
+
 static const struct of_device_id syscon_gpio_ids[] = {
 	{
 		.compatible	= "cirrus,ep7209-mctrl-gpio",
@@ -203,6 +267,10 @@ static const struct of_device_id syscon_gpio_ids[] = {
 		.compatible	= "rockchip,rk3328-grf-gpio",
 		.data		= &rockchip_rk3328_gpio_mute,
 	},
+	{
+		.compatible	= "xylon,logicvc-3.02.a-gpio",
+		.data		= &logicvc_3_gpio,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, syscon_gpio_ids);
-- 
2.23.0