gpio: 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.

Add a minimalistic GPIO driver to drive these GPIOs, using a syscon
regmap when available.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20191203141243.251058-5-paul.kocialkowski@bootlin.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 8adffd42f8cb0559031837899b25c7f6ba23c313..79f153b1da7e2d9b52e14226cf45df85b9aa7c4e 100644 (file)
--- 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 34eb8b2b12dd656c9e00e4ded6fa3881e015f68b..ba53f1fcde3a359182c9ada5187e5a74102d3d9d 100644 (file)
--- 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 (file)
index 0000000..015632c
--- /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@bootlin.com>
+ */
+
+#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, &reg, &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, &reg, &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@bootlin.com>");
+MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
+MODULE_LICENSE("GPL");