gpio: add Technologic I2C-FPGA gpio support

This driver is generic and aims to support all Technologic Systems's
boards embedding FPGA GPIOs with an I2C interface.

This driver supports TS-4900, TS-7970, TS-7990 and TS-4100 series.

Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 825cf3c..5eb7c86 100644 (file)
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -777,6 +777,13 @@ config GPIO_TPIC2810
          To compile this driver as a module, choose M here: the module will
          be called gpio-tpic2810.
 
+config GPIO_TS4900
+       tristate "Technologic Systems FPGA I2C GPIO"
+       select REGMAP_I2C
+       help
+         Say yes here to enabled the GPIO driver for Technologic's FPGA core.
+         Series supported include TS-4100, TS-4900, TS-7970 and TS-7990.
+
 endmenu
 
 menu "MFD GPIO expanders"

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 9665028..691fb3a 100644 (file)
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -112,6 +112,7 @@ obj-$(CONFIG_GPIO_TPS6586X) += gpio-tps6586x.o
 obj-$(CONFIG_GPIO_TPS65910)    += gpio-tps65910.o
 obj-$(CONFIG_GPIO_TPS65912)    += gpio-tps65912.o
 obj-$(CONFIG_GPIO_TS4800)      += gpio-ts4800.o
+obj-$(CONFIG_GPIO_TS4900)      += gpio-ts4900.o
 obj-$(CONFIG_GPIO_TS5500)      += gpio-ts5500.o
 obj-$(CONFIG_GPIO_TWL4030)     += gpio-twl4030.o
 obj-$(CONFIG_GPIO_TWL6040)     += gpio-twl6040.o

diff --git a/drivers/gpio/gpio-ts4900.c b/drivers/gpio/gpio-ts4900.c
new file mode 100644 (file)
index 0000000..9dd9aca
--- /dev/null
+++ b/drivers/gpio/gpio-ts4900.c
@@ -0,0 +1,190 @@
+/*
+ * Digital I/O driver for Technologic Systems I2C FPGA Core
+ *
+ * Copyright (C) 2015 Technologic Systems
+ * Copyright (C) 2016 Savoir-Faire Linux
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether expressed or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ */
+
+#include <linux/gpio/driver.h>
+#include <linux/i2c.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#define DEFAULT_PIN_NUMBER     32
+/*
+ * Register bits used by the GPIO device
+ * Some boards, such as TS-7970 do not have a separate input bit
+ */
+#define TS4900_GPIO_OE         0x01
+#define TS4900_GPIO_OUT                0x02
+#define TS4900_GPIO_IN         0x04
+#define TS7970_GPIO_IN         0x02
+
+struct ts4900_gpio_priv {
+       struct regmap *regmap;
+       struct gpio_chip gpio_chip;
+       unsigned int input_bit;
+};
+
+static int ts4900_gpio_get_direction(struct gpio_chip *chip,
+                                    unsigned int offset)
+{
+       struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+       unsigned int reg;
+
+       regmap_read(priv->regmap, offset, &reg);
+
+       return !(reg & TS4900_GPIO_OE);
+}
+
+static int ts4900_gpio_direction_input(struct gpio_chip *chip,
+                                      unsigned int offset)
+{
+       struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+
+       /*
+        * This will clear the output enable bit, the other bits are
+        * dontcare when this is cleared
+        */
+       return regmap_write(priv->regmap, offset, 0);
+}
+
+static int ts4900_gpio_direction_output(struct gpio_chip *chip,
+                                       unsigned int offset, int value)
+{
+       struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+       int ret;
+
+       if (value)
+               ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE |
+                                                        TS4900_GPIO_OUT);
+       else
+               ret = regmap_write(priv->regmap, offset, TS4900_GPIO_OE);
+
+       return ret;
+}
+
+static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+       struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+       unsigned int reg;
+
+       regmap_read(priv->regmap, offset, &reg);
+
+       return !!(reg & priv->input_bit);
+}
+
+static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
+                           int value)
+{
+       struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+
+       if (value)
+               regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT,
+                                  TS4900_GPIO_OUT);
+       else
+               regmap_update_bits(priv->regmap, offset, TS4900_GPIO_OUT, 0);
+}
+
+static const struct regmap_config ts4900_regmap_config = {
+       .reg_bits = 16,
+       .val_bits = 8,
+};
+
+static struct gpio_chip template_chip = {
+       .label                  = "ts4900-gpio",
+       .owner                  = THIS_MODULE,
+       .get_direction          = ts4900_gpio_get_direction,
+       .direction_input        = ts4900_gpio_direction_input,
+       .direction_output       = ts4900_gpio_direction_output,
+       .get                    = ts4900_gpio_get,
+       .set                    = ts4900_gpio_set,
+       .base                   = -1,
+       .can_sleep              = true,
+};
+
+static const struct of_device_id ts4900_gpio_of_match_table[] = {
+       {
+               .compatible = "technologic,ts4900-gpio",
+               .data = (void *)TS4900_GPIO_IN,
+       }, {
+               .compatible = "technologic,ts7970-gpio",
+               .data = (void *)TS7970_GPIO_IN,
+       },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ts4900_gpio_of_match_table);
+
+static int ts4900_gpio_probe(struct i2c_client *client,
+                       const struct i2c_device_id *id)
+{
+       const struct of_device_id *match;
+       struct ts4900_gpio_priv *priv;
+       u32 ngpio;
+       int ret;
+
+       match = of_match_device(ts4900_gpio_of_match_table, &client->dev);
+       if (!match)
+               return -EINVAL;
+
+       if (of_property_read_u32(client->dev.of_node, "ngpios", &ngpio))
+               ngpio = DEFAULT_PIN_NUMBER;
+
+       priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
+
+       priv->gpio_chip = template_chip;
+       priv->gpio_chip.label = "ts4900-gpio";
+       priv->gpio_chip.ngpio = ngpio;
+       priv->gpio_chip.parent = &client->dev;
+       priv->input_bit = (uintptr_t)match->data;
+
+       priv->regmap = devm_regmap_init_i2c(client, &ts4900_regmap_config);
+       if (IS_ERR(priv->regmap)) {
+               ret = PTR_ERR(priv->regmap);
+               dev_err(&client->dev, "Failed to allocate register map: %d\n",
+                       ret);
+               return ret;
+       }
+
+       ret = devm_gpiochip_add_data(&client->dev, &priv->gpio_chip, priv);
+       if (ret < 0) {
+               dev_err(&client->dev, "Unable to register gpiochip\n");
+               return ret;
+       }
+
+       i2c_set_clientdata(client, priv);
+
+       return 0;
+}
+
+static const struct i2c_device_id ts4900_gpio_id_table[] = {
+       { "ts4900-gpio", },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, ts4900_gpio_id_table);
+
+static struct i2c_driver ts4900_gpio_driver = {
+       .driver = {
+               .name = "ts4900-gpio",
+               .of_match_table = ts4900_gpio_of_match_table,
+       },
+       .probe = ts4900_gpio_probe,
+       .id_table = ts4900_gpio_id_table,
+};
+module_i2c_driver(ts4900_gpio_driver);
+
+MODULE_AUTHOR("Technologic Systems");
+MODULE_DESCRIPTION("GPIO interface for Technologic Systems I2C-FPGA core");
+MODULE_LICENSE("GPL");