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.
Add a minimalistic GPIO driver to drive these GPIOs, using a syscon
regmap when available.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
---
drivers/gpio/Kconfig | 6 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-logicvc.c | 170 ++++++++++++++++++++++++++++++++++++
3 files changed, 177 insertions(+)
create mode 100644 drivers/gpio/gpio-logicvc.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e9516393c971..3b0a8cfc5f17 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -312,6 +312,12 @@ config GPIO_IXP4XX
IXP4xx series of chips.
If unsure, say N.
+config GPIO_LOGICVC
+ tristate "Xylon LogiCVC GPIO support"
+ depends on MFD_SYSCON && OF
+ help
+ Say yes here to support GPIO functionality of the Xylon LogiCVC
+ programmable logic block.
config GPIO_LOONGSON
bool "Loongson-2/3 GPIO support"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 34eb8b2b12dd..ba53f1fcde3a 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_GPIO_IT87) += gpio-it87.o
obj-$(CONFIG_GPIO_IXP4XX) += gpio-ixp4xx.o
obj-$(CONFIG_GPIO_JANZ_TTL) += gpio-janz-ttl.o
obj-$(CONFIG_GPIO_KEMPLD) += gpio-kempld.o
+obj-$(CONFIG_GPIO_LOGICVC) += gpio-logicvc.o
obj-$(CONFIG_GPIO_LOONGSON1) += gpio-loongson1.o
obj-$(CONFIG_GPIO_LOONGSON) += gpio-loongson.o
obj-$(CONFIG_GPIO_LP3943) += gpio-lp3943.o
diff --git a/drivers/gpio/gpio-logicvc.c b/drivers/gpio/gpio-logicvc.c
new file mode 100644
index 000000000000..015632cf159f
--- /dev/null
+++ b/drivers/gpio/gpio-logicvc.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Bootlin
+ * Author: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
+ */
+
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#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
+
+struct logicvc_gpio {
+ struct gpio_chip chip;
+ struct regmap *regmap;
+};
+
+static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, 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 = BIT(offset);
+}
+
+static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
+ unsigned int reg, bit, value;
+ int ret;
+
+ logicvc_gpio_offset(logicvc, offset, ®, &bit);
+
+ ret = regmap_read(logicvc->regmap, reg, &value);
+ if (ret)
+ return ret;
+
+ return !!(value & bit);
+}
+
+static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
+ unsigned int reg, bit;
+
+ logicvc_gpio_offset(logicvc, offset, ®, &bit);
+
+ regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
+}
+
+static int logicvc_gpio_direction_output(struct gpio_chip *chip,
+ unsigned offset, int value)
+{
+ /* Pins are always configured as output, so just set the value. */
+ logicvc_gpio_set(chip, offset, value);
+
+ return 0;
+}
+
+static struct regmap_config logicvc_gpio_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .name = "logicvc-gpio",
+};
+
+static int logicvc_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *of_node = dev->of_node;
+ struct logicvc_gpio *logicvc;
+ int ret;
+
+ logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
+ if (!logicvc)
+ return -ENOMEM;
+
+ /* Try to get regmap from parent first. */
+ logicvc->regmap = syscon_node_to_regmap(of_node->parent);
+
+ /* Grab our own regmap if that fails. */
+ if (IS_ERR(logicvc->regmap)) {
+ struct resource res;
+ void __iomem *base;
+
+ ret = of_address_to_resource(of_node, 0, &res);
+ if (ret) {
+ dev_err(dev, "Failed to get resource from address\n");
+ return ret;
+ }
+
+ base = devm_ioremap_resource(dev, &res);
+ if (IS_ERR(base)) {
+ dev_err(dev, "Failed to map I/O base\n");
+ return PTR_ERR(base);
+ }
+
+ logicvc_gpio_regmap_config.max_register = resource_size(&res) -
+ logicvc_gpio_regmap_config.reg_stride;
+
+ logicvc->regmap =
+ devm_regmap_init_mmio(dev, base,
+ &logicvc_gpio_regmap_config);
+ if (IS_ERR(logicvc->regmap)) {
+ dev_err(dev, "Failed to create regmap for I/O\n");
+ return PTR_ERR(logicvc->regmap);
+ }
+ }
+
+ logicvc->chip.parent = dev;
+ logicvc->chip.owner = THIS_MODULE;
+ logicvc->chip.label = dev_name(dev);
+ logicvc->chip.base = -1;
+ logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
+ LOGICVC_POWER_CTRL_GPIO_BITS;
+ logicvc->chip.get = logicvc_gpio_get;
+ logicvc->chip.set = logicvc_gpio_set;
+ logicvc->chip.direction_output = logicvc_gpio_direction_output;
+
+ platform_set_drvdata(pdev, logicvc);
+
+ return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
+}
+
+static const struct of_device_id logicivc_gpio_of_table[] = {
+ {
+ .compatible = "xylon,logicvc-3.02.a-gpio",
+ },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
+
+static struct platform_driver logicvc_gpio_driver = {
+ .driver = {
+ .name = "gpio-logicvc",
+ .of_match_table = logicivc_gpio_of_table,
+ },
+ .probe = logicvc_gpio_probe,
+};
+
+module_platform_driver(logicvc_gpio_driver);
+
+MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
+MODULE_LICENSE("GPL");
--
2.24.0
