[PATCH 3/6] gpio: Add Delta TN48M CPLD GPIO driver

From: Robert Marko
Date: Fri Apr 30 2021 - 08:35:37 EST

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

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

Since there is no logical GPIO numbering arbitrary one is used
along dt-bindings to make it humanly readable.

Signed-off-by: Robert Marko <robert.marko@xxxxxxxxxx>
---
drivers/gpio/Kconfig | 12 +++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-tn48m.c | 191 ++++++++++++++++++++++++++++++++++++++
drivers/mfd/tn48m-cpld.c | 6 +-
include/linux/mfd/tn48m.h | 3 +
5 files changed, 212 insertions(+), 1 deletion(-)
create mode 100644 drivers/gpio/gpio-tn48m.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index e3607ec4c2e8..e17d4416786a 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1310,6 +1310,18 @@ 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
+ depends on OF_GPIO
+ 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 c58a90a3c3b1..271fb806475e 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -145,6 +145,7 @@ 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..4e859e4c339c
--- /dev/null
+++ b/drivers/gpio/gpio-tn48m.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Delta TN48M CPLD GPIO driver
+ *
+ * Copyright 2020 Sartura Ltd
+ *
+ * Author: Robert Marko <robert.marko@xxxxxxxxxx>
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/mfd/tn48m.h>
+#include <dt-bindings/gpio/tn48m-gpio.h>
+
+struct tn48m_gpio {
+ struct gpio_chip chip;
+ struct tn48m_data *data;
+};
+
+static int tn48m_gpio_get_direction(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ switch (offset) {
+ case SFP_TX_DISABLE_52:
+ case SFP_TX_DISABLE_51:
+ case SFP_TX_DISABLE_50:
+ case SFP_TX_DISABLE_49:
+ return GPIO_LINE_DIRECTION_OUT;
+ case SFP_PRESENT_52:
+ case SFP_PRESENT_51:
+ case SFP_PRESENT_50:
+ case SFP_PRESENT_49:
+ case SFP_LOS_52:
+ case SFP_LOS_51:
+ case SFP_LOS_50:
+ case SFP_LOS_49:
+ return GPIO_LINE_DIRECTION_IN;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int tn48m_gpio_get_reg(unsigned int offset)
+{
+ switch (offset) {
+ case SFP_TX_DISABLE_52:
+ case SFP_TX_DISABLE_51:
+ case SFP_TX_DISABLE_50:
+ case SFP_TX_DISABLE_49:
+ return SFP_TX_DISABLE;
+ case SFP_PRESENT_52:
+ case SFP_PRESENT_51:
+ case SFP_PRESENT_50:
+ case SFP_PRESENT_49:
+ return SFP_PRESENT;
+ case SFP_LOS_52:
+ case SFP_LOS_51:
+ case SFP_LOS_50:
+ case SFP_LOS_49:
+ return SFP_LOS;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int tn48m_gpio_get_mask(unsigned int offset)
+{
+ switch (offset) {
+ case SFP_TX_DISABLE_52:
+ case SFP_PRESENT_52:
+ case SFP_LOS_52:
+ return BIT(3);
+ case SFP_TX_DISABLE_51:
+ case SFP_PRESENT_51:
+ case SFP_LOS_51:
+ return BIT(2);
+ case SFP_TX_DISABLE_50:
+ case SFP_PRESENT_50:
+ case SFP_LOS_50:
+ return BIT(1);
+ case SFP_TX_DISABLE_49:
+ case SFP_PRESENT_49:
+ case SFP_LOS_49:
+ return BIT(0);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int tn48m_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct tn48m_gpio *gpio = gpiochip_get_data(chip);
+ unsigned int regval;
+ int ret;
+
+ ret = regmap_read(gpio->data->regmap,
+ tn48m_gpio_get_reg(offset),
+ &regval);
+ if (ret < 0)
+ return ret;
+
+ return regval & tn48m_gpio_get_mask(offset);
+}
+
+static void tn48m_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ struct tn48m_gpio *gpio = gpiochip_get_data(chip);
+
+ regmap_update_bits(gpio->data->regmap,
+ tn48m_gpio_get_reg(offset),
+ tn48m_gpio_get_mask(offset),
+ value ? tn48m_gpio_get_mask(offset) : 0);
+}
+
+static int tn48m_gpio_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ tn48m_gpio_set(chip, offset, value);
+
+ return 0;
+}
+
+/*
+ * Required for SFP as it calls gpiod_direction_input()
+ * and if its missing TX disable GPIO will print an
+ * error and not be controlled anymore.
+ */
+static int tn48m_gpio_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ return 0;
+}
+
+static const struct gpio_chip tn48m_template_chip = {
+ .label = "tn48m-gpio",
+ .owner = THIS_MODULE,
+ .get_direction = tn48m_gpio_get_direction,
+ .direction_output = tn48m_gpio_direction_output,
+ .direction_input = tn48m_gpio_direction_input,
+ .get = tn48m_gpio_get,
+ .set = tn48m_gpio_set,
+ .base = -1,
+ .ngpio = 12,
+ .can_sleep = true,
+};
+
+static int tn48m_gpio_probe(struct platform_device *pdev)
+{
+ struct tn48m_gpio *gpio;
+ int ret;
+
+ gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
+ if (!gpio)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, gpio);
+
+ gpio->data = dev_get_drvdata(pdev->dev.parent);
+ gpio->chip = tn48m_template_chip;
+ gpio->chip.parent = gpio->data->dev;
+
+ ret = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct platform_device_id tn48m_gpio_id_table[] = {
+ { "delta,tn48m-gpio", },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, tn48m_gpio_id_table);
+
+static struct platform_driver tn48m_gpio_driver = {
+ .driver = {
+ .name = "tn48m-gpio",
+ },
+ .probe = tn48m_gpio_probe,
+ .id_table = tn48m_gpio_id_table,
+};
+module_platform_driver(tn48m_gpio_driver);
+
+MODULE_AUTHOR("Robert Marko <robert.marko@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Delta TN48M CPLD GPIO driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/tn48m-cpld.c b/drivers/mfd/tn48m-cpld.c
index b84510fb630a..f22a15ddd22d 100644
--- a/drivers/mfd/tn48m-cpld.c
+++ b/drivers/mfd/tn48m-cpld.c
@@ -17,7 +17,11 @@
#include <linux/regmap.h>
#include <linux/slab.h>

-static const struct mfd_cell tn48m_cell[] = {};
+static const struct mfd_cell tn48m_cell[] = {
+ {
+ .name = "delta,tn48m-gpio",
+ }
+};

static const struct regmap_config tn48m_regmap_config = {
.reg_bits = 8,
diff --git a/include/linux/mfd/tn48m.h b/include/linux/mfd/tn48m.h
index 551c550efa54..9cc2b04c8d69 100644
--- a/include/linux/mfd/tn48m.h
+++ b/include/linux/mfd/tn48m.h
@@ -19,6 +19,9 @@
#define BOARD_ID_TN48M 0xa
#define BOARD_ID_TN48M_P 0xb
#define CPLD_CODE_VERSION 0x2
+#define SFP_TX_DISABLE 0x31
+#define SFP_PRESENT 0x3a
+#define SFP_LOS 0x40

struct tn48m_data {
struct device *dev;
--
2.31.1