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Message-Id: <1471015009-5925-3-git-send-email-lucile.quirion@savoirfairelinux.com>
Date: Fri, 12 Aug 2016 11:16:49 -0400
From: Lucile Quirion <lucile.quirion@...oirfairelinux.com>
To: linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org
Cc: Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>,
kernel@...oirfairelinux.com,
Lucile Quirion <lucile.quirion@...oirfairelinux.com>
Subject: [PATCH v4 2/2] 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@...oirfairelinux.com>
---
drivers/gpio/Kconfig | 7 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-ts4900.c | 190 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 198 insertions(+)
create mode 100644 drivers/gpio/gpio-ts4900.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 98dd47a..3f84574 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -779,6 +779,13 @@ 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 2a035ed..4dcc21f 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -110,6 +110,7 @@ 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
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, ®);
+
+ 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, ®);
+
+ 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");
--
2.5.5
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