Delta TN48M CPLD is used as a GPIO expander for the SFP GPIOs.

It is a mix of input only and output only pins.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
---
Changes in v2:
* Rewrite to use simple I2C MFD and GPIO regmap
* Drop DT bindings for pin numbering

 drivers/gpio/Kconfig      | 12 ++++++
 drivers/gpio/Makefile     |  1 +
 drivers/gpio/gpio-tn48m.c | 89 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+)
 create mode 100644 drivers/gpio/gpio-tn48m.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 1dd0ec6727fd..46caf72960e6 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig

@@ -1332,6 +1332,18 @@ config GPIO_TIMBERDALE
        help
        Add support for the GPIO IP in the timberdale FPGA.

+config GPIO_TN48M_CPLD
+       tristate "Delta Networks TN48M switch CPLD GPIO driver"
+       depends on MFD_TN48M_CPLD
+       select GPIO_REGMAP
+       help
+         This enables support for the GPIOs found on the Delta
+         Networks TN48M switch CPLD.
+         They are used for inputs and outputs on the SFP slots.
+
+         This driver can also be built as a module. If so, the
+         module will be called gpio-tn48m.
+
 config GPIO_TPS65086
        tristate "TI TPS65086 GPO"
        depends on MFD_TPS65086

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d7c81e1611a4..07fa6419305f 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile

@@ -147,6 +147,7 @@ obj-$(CONFIG_GPIO_TEGRA186)         += gpio-tegra186.o
 obj-$(CONFIG_GPIO_TEGRA)               += gpio-tegra.o
 obj-$(CONFIG_GPIO_THUNDERX)            += gpio-thunderx.o
 obj-$(CONFIG_GPIO_TIMBERDALE)          += gpio-timberdale.o
+obj-$(CONFIG_GPIO_TN48M_CPLD)          += gpio-tn48m.o
 obj-$(CONFIG_GPIO_TPIC2810)            += gpio-tpic2810.o
 obj-$(CONFIG_GPIO_TPS65086)            += gpio-tps65086.o
 obj-$(CONFIG_GPIO_TPS65218)            += gpio-tps65218.o

diff --git a/drivers/gpio/gpio-tn48m.c b/drivers/gpio/gpio-tn48m.c
new file mode 100644
index 000000000000..41484c002826
--- /dev/null
+++ b/drivers/gpio/gpio-tn48m.c

@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Delta TN48M CPLD GPIO driver
+ *
+ * Copyright 2021 Sartura Ltd
+ *
+ * Author: Robert Marko <robert.marko@sartura.hr>
+ */
+
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+enum tn48m_gpio_type {
+       TN48M_SFP_TX_DISABLE = 1,
+       TN48M_SFP_PRESENT,
+       TN48M_SFP_LOS,
+};
+
+static int tn48m_gpio_probe(struct platform_device *pdev)
+{
+       struct gpio_regmap_config config = {0};
+       enum tn48m_gpio_type type;
+       struct regmap *regmap;
+       u32 base;
+       int ret;
+
+       if (!pdev->dev.parent)
+               return -ENODEV;
+
+       type = (uintptr_t)device_get_match_data(&pdev->dev);
+       if (!type)
+               return -ENODEV;
+
+       ret = device_property_read_u32(&pdev->dev, "reg", &base);
+       if (ret)
+               return -EINVAL;
+
+       regmap = dev_get_regmap(pdev->dev.parent, NULL);
+       if (!regmap)
+               return -ENODEV;
+
+       config.regmap = regmap;
+       config.parent = &pdev->dev;
+       config.ngpio = 4;
+
+       switch (type) {
+       case TN48M_SFP_TX_DISABLE:
+               config.reg_set_base = base;
+               break;
+       case TN48M_SFP_PRESENT:
+               config.reg_dat_base = base;
+               break;
+       case TN48M_SFP_LOS:
+               config.reg_dat_base = base;
+               break;
+       default:
+               dev_err(&pdev->dev, "unknown type %d\n", type);
+               return -ENODEV;
+       }
+
+       return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(&pdev->dev, &config));
+}
+
+static const struct of_device_id tn48m_gpio_of_match[] = {
+       { .compatible = "delta,tn48m-gpio-sfp-tx-disable", .data = (void *)TN48M_SFP_TX_DISABLE },
+       { .compatible = "delta,tn48m-gpio-sfp-present", .data = (void *)TN48M_SFP_PRESENT },
+       { .compatible = "delta,tn48m-gpio-sfp-los", .data = (void *)TN48M_SFP_LOS },
+       { }
+};
+MODULE_DEVICE_TABLE(of, tn48m_gpio_of_match);
+
+static struct platform_driver tn48m_gpio_driver = {
+       .driver = {
+               .name = "delta-tn48m-gpio",
+               .of_match_table = tn48m_gpio_of_match,
+       },
+       .probe = tn48m_gpio_probe,
+};
+module_platform_driver(tn48m_gpio_driver);
+
+MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
+MODULE_DESCRIPTION("Delta TN48M CPLD GPIO driver");
+MODULE_LICENSE("GPL");
--

2.31.1