* [PATCH v2 2/2] gpio: add Technologic I2C-FPGA gpio support
2016-08-08 16:46 [PATCH v2 0/2] Technologic I2C-FPGA gpio support Lucile Quirion
2016-08-08 16:46 ` [PATCH v2 1/2] gpio: add bindings for Technologic I2C-FPGA gpio controller Lucile Quirion
@ 2016-08-08 16:46 ` Lucile Quirion
2016-08-11 13:32 ` Linus Walleij
1 sibling, 1 reply; 5+ messages in thread
From: Lucile Quirion @ 2016-08-08 16:46 UTC (permalink / raw)
To: linux-kernel, linux-gpio
Cc: Linus Walleij, Alexandre Courbot, kernel, Lucile Quirion
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>
---
drivers/gpio/Kconfig | 6 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-ts4900.c | 238 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 245 insertions(+)
create mode 100644 drivers/gpio/gpio-ts4900.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 98dd47a..3320616 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -779,6 +779,12 @@ 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"
+ 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..104d1e0
--- /dev/null
+++ b/drivers/gpio/gpio-ts4900.c
@@ -0,0 +1,238 @@
+/*
+ * 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>
+
+#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_OD 0x02
+#define TS4900_GPIO_ID 0x04
+#define TS7970_GPIO_ID 0x02
+
+struct ts4900_gpio_priv {
+ struct i2c_client *client;
+ struct gpio_chip gpio_chip;
+ unsigned int input_bit;
+};
+
+static int ts4900_gpio_write(struct i2c_client *client, u16 addr, u8 data)
+{
+ struct i2c_msg msg;
+ u8 buf[3];
+ int ret;
+
+ buf[0] = addr >> 8;
+ buf[1] = addr & 0xFF;
+ buf[2] = data;
+
+ msg.addr = client->addr;
+ msg.flags = 0;
+ msg.len = 3;
+ msg.buf = buf;
+
+ ret = i2c_transfer(client->adapter, &msg, 1);
+ if (ret != 1) {
+ dev_err(&client->dev, "%s: write error, ret=%d\n",
+ __func__, ret);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int ts4900_gpio_read(struct i2c_client *client, u16 addr)
+{
+ struct i2c_msg msgs[2];
+ u8 buf[2];
+ int ret;
+
+ buf[0] = addr >> 8;
+ buf[1] = addr & 0xFF;
+
+ msgs[0].addr = client->addr;
+ msgs[0].flags = 0;
+ msgs[0].len = 2;
+ msgs[0].buf = buf;
+
+ msgs[1].addr = client->addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].len = 1;
+ msgs[1].buf = buf;
+
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+ if (ret != ARRAY_SIZE(msgs)) {
+ dev_err(&client->dev, "%s: read error, ret=%d\n",
+ __func__, ret);
+ return -EIO;
+ }
+
+ return buf[0];
+}
+
+static int __ts4900_gpio_direction_output(struct i2c_client *client, int gpio,
+ int value)
+{
+ u8 reg = 0;
+
+ if (value)
+ reg = TS4900_GPIO_OD | TS4900_GPIO_OE;
+ else
+ reg = TS4900_GPIO_OE;
+
+ return ts4900_gpio_write(client, gpio, reg);
+}
+
+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 ts4900_gpio_write(priv->client, 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);
+
+ return __ts4900_gpio_direction_output(priv->client, offset, value);
+}
+
+static int ts4900_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+ int ret;
+ u8 reg;
+
+ reg = ts4900_gpio_read(priv->client, offset);
+
+ ret = (reg & priv->input_bit) ? 1 : 0;
+
+ return ret;
+}
+
+static void ts4900_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ struct ts4900_gpio_priv *priv = gpiochip_get_data(chip);
+
+ __ts4900_gpio_direction_output(priv->client, offset, value);
+}
+
+static struct gpio_chip template_chip = {
+ .label = "ts4900-gpio",
+ .owner = THIS_MODULE,
+ .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_ID,
+ }, {
+ .compatible = "technologic,ts7970-gpio",
+ .data = (void *)TS7970_GPIO_ID,
+ },
+ { /* 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;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA))
+ return -EIO;
+
+ 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;
+
+ i2c_set_clientdata(client, priv);
+
+ priv->client = client;
+ 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;
+
+ ret = gpiochip_add_data(&priv->gpio_chip, priv);
+ if (ret < 0) {
+ dev_err(&client->dev, "Unable to register gpiochip\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int ts4900_gpio_remove(struct i2c_client *client)
+{
+ struct ts4900_gpio_priv *priv = i2c_get_clientdata(client);
+
+ gpiochip_remove(&priv->gpio_chip);
+
+ 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,
+ .remove = ts4900_gpio_remove,
+ .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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