Add a very abridged version of SX150x driver from Linux. New, "pinctrl"
version of the driver was used as a base. As it was already mentioned
this driver supports very limited amount of the original functionality,
and the following are the features that were dropped:
- Interrupt support
- Support for any chip other that SX150x (due to lack of HW to test
with)
- Any pinctlr-like functions: pull-up/pull-down, open-drain,
etc. configuration
Signed-off-by: Andrey Smirnov <[email protected]>
---
drivers/gpio/Kconfig | 8 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-sx150x.c | 274 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 283 insertions(+)
create mode 100644 drivers/gpio/gpio-sx150x.c
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index fe62778..434c568 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -124,6 +124,14 @@ config GPIO_DESIGNWARE
help
Say Y or M here to build support for the Synopsys DesignWare APB
GPIO block.
+
+config GPIO_SX150X
+ bool "Semtec SX150x I/O ports"
+ depends on I2C
+ help
+ Say Y here to build support for the Semtec Sx150x I2C GPIO
+ expander chip.
+
endmenu
endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 248100f..7442c44 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -19,3 +19,4 @@ obj-$(CONFIG_GPIO_STMPE) += gpio-stmpe.o
obj-$(CONFIG_GPIO_TEGRA) += gpio-tegra.o
obj-$(CONFIG_GPIO_DESIGNWARE) += gpio-dw.o
obj-$(CONFIG_GPIO_VF610) += gpio-vf610.o
+obj-$(CONFIG_GPIO_SX150X) += gpio-sx150x.o
diff --git a/drivers/gpio/gpio-sx150x.c b/drivers/gpio/gpio-sx150x.c
new file mode 100644
index 0000000..7b8cfb5
--- /dev/null
+++ b/drivers/gpio/gpio-sx150x.c
@@ -0,0 +1,274 @@
+/*
+ * Driver for SX150x I2C GPIO expanders
+ *
+ * This code was ported from linux-4.9 kernel driver by
+ * Andrey Smirnov <[email protected]>.
+ *
+ * Orginal code with it's copyright info can be found in
+ * drivers/pinctrl/pinctrl-sx150x.c
+ *
+ * Note: That although linux driver was converted from being a GPIO
+ * subsystem to Pinctrl subsytem driver, due to Barebox's lack of
+ * similar provisions this driver is still a GPIO driver.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <malloc.h>
+#include <driver.h>
+#include <xfuncs.h>
+#include <errno.h>
+#include <i2c/i2c.h>
+#include <regmap.h>
+
+#include <gpio.h>
+#include <of_device.h>
+
+enum {
+ SX150X_123 = 0,
+ SX150X_456,
+ SX150X_789,
+};
+
+enum {
+ SX150X_MAX_REGISTER = 0xad,
+};
+
+struct sx150x_device_data {
+ u8 model;
+ u8 reg_dir;
+ u8 reg_data;
+ u8 ngpios;
+};
+
+struct sx150x_gpio {
+ struct device *dev;
+ struct i2c_client *client;
+ struct gpio_chip gpio;
+ struct regmap *regmap;
+ const struct sx150x_device_data *data;
+};
+
+static const struct sx150x_device_data sx1503q_device_data = {
+ .model = SX150X_123,
+ .reg_dir = 0x02,
+ .reg_data = 0x00,
+ .ngpios = 16,
+};
+
+static struct sx150x_gpio *to_sx150x_gpio(struct gpio_chip *gpio)
+{
+ return container_of(gpio, struct sx150x_gpio, gpio);
+}
+
+static int sx150x_gpio_get_direction(struct gpio_chip *gpio,
+ unsigned int offset)
+{
+ struct sx150x_gpio *sx150x = to_sx150x_gpio(gpio);
+ unsigned int value;
+ int ret;
+
+ ret = regmap_read(sx150x->regmap, sx150x->data->reg_dir, &value);
+ if (ret < 0)
+ return ret;
+
+ return !!(value & BIT(offset));
+}
+
+static int sx150x_gpio_get(struct gpio_chip *gpio, unsigned int offset)
+{
+ struct sx150x_gpio *sx150x = to_sx150x_gpio(gpio);
+ unsigned int value;
+ int ret;
+
+ ret = regmap_read(sx150x->regmap, sx150x->data->reg_data, &value);
+ if (ret < 0)
+ return ret;
+
+ return !!(value & BIT(offset));
+}
+
+static int __sx150x_gpio_set(struct sx150x_gpio *sx150x, unsigned int offset,
+ int value)
+{
+ return regmap_write_bits(sx150x->regmap, sx150x->data->reg_data,
+ BIT(offset), value ? BIT(offset) : 0);
+}
+
+
+static void sx150x_gpio_set(struct gpio_chip *gpio, unsigned int offset,
+ int value)
+{
+ __sx150x_gpio_set(to_sx150x_gpio(gpio), offset, value);
+}
+
+static int sx150x_gpio_direction_input(struct gpio_chip *gpio,
+ unsigned int offset)
+{
+ struct sx150x_gpio *sx150x = to_sx150x_gpio(gpio);
+
+ return regmap_write_bits(sx150x->regmap,
+ sx150x->data->reg_dir,
+ BIT(offset), BIT(offset));
+}
+
+static int sx150x_gpio_direction_output(struct gpio_chip *gpio,
+ unsigned int offset, int value)
+{
+ struct sx150x_gpio *sx150x = to_sx150x_gpio(gpio);
+ int ret;
+
+ ret = __sx150x_gpio_set(sx150x, offset, value);
+ if (ret < 0)
+ return ret;
+
+ return regmap_write_bits(sx150x->regmap,
+ sx150x->data->reg_dir,
+ BIT(offset), 0);
+}
+
+static int sx150x_regmap_reg_width(struct sx150x_gpio *sx150x,
+ unsigned int reg)
+{
+ return sx150x->data->ngpios;
+}
+
+/*
+ * In order to mask the differences between 16 and 8 bit expander
+ * devices we set up a sligthly ficticious regmap that pretends to be
+ * a set of 16-bit registers and transparently reconstructs those
+ * registers via multiple I2C/SMBus reads
+ *
+ * This way the rest of the driver code, interfacing with the chip via
+ * regmap API, can work assuming that each GPIO pin is represented by
+ * a group of bits at an offset proportioan to GPIO number within a
+ * given register.
+ *
+ */
+static int sx150x_regmap_reg_read(void *context, unsigned int reg,
+ unsigned int *result)
+{
+ int ret, n;
+ struct sx150x_gpio *sx150x = context;
+ struct i2c_client *i2c = sx150x->client;
+ const int width = sx150x_regmap_reg_width(sx150x, reg);
+ unsigned int idx, val;
+
+ /*
+ * There are four potential cases coverd by this function:
+ *
+ * 1) 8-pin chip, single configuration bit register
+ *
+ * This is trivial the code below just needs to read:
+ * reg [ 7 6 5 4 3 2 1 0 ]
+ *
+ * 2) 16-pin chip, single configuration bit register
+ *
+ * The read will be done as follows:
+ * reg [ f e d c b a 9 8 ]
+ * reg + 1 [ 7 6 5 4 3 2 1 0 ]
+ *
+ */
+
+ for (n = width, val = 0, idx = reg; n > 0; n -= 8, idx++) {
+ val <<= 8;
+
+ ret = i2c_smbus_read_byte_data(i2c, idx);
+ if (ret < 0)
+ return ret;
+
+ val |= ret;
+ }
+
+ *result = val;
+
+ return 0;
+}
+
+static int sx150x_regmap_reg_write(void *context, unsigned int reg,
+ unsigned int val)
+{
+ int ret, n;
+ struct sx150x_gpio *sx150x = context;
+ struct i2c_client *i2c = sx150x->client;
+ const int width = sx150x_regmap_reg_width(sx150x, reg);
+
+ n = width - 8;
+ do {
+ const u8 byte = (val >> n) & 0xff;
+
+ ret = i2c_smbus_write_byte_data(i2c, reg, byte);
+ if (ret < 0)
+ return ret;
+
+ reg++;
+ n -= 8;
+ } while (n >= 0);
+
+ return 0;
+}
+
+static const struct regmap_config sx150x_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 16,
+
+ .max_register = SX150X_MAX_REGISTER,
+};
+
+static const struct regmap_bus sx150x_regmap_bus = {
+ .reg_read = sx150x_regmap_reg_read,
+ .reg_write = sx150x_regmap_reg_write,
+};
+
+static struct gpio_ops sx150x_gpio_ops = {
+ .direction_input = sx150x_gpio_direction_input,
+ .direction_output = sx150x_gpio_direction_output,
+ .get_direction = sx150x_gpio_get_direction,
+ .get = sx150x_gpio_get,
+ .set = sx150x_gpio_set,
+};
+
+static int sx150x_probe(struct device_d *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct sx150x_gpio *sx150x;
+ const struct sx150x_device_data *data;
+
+ data = of_device_get_match_data(dev);
+ if (!data)
+ return -EINVAL;
+
+ sx150x = xzalloc(sizeof(*sx150x));
+
+ sx150x->regmap = regmap_init(dev, &sx150x_regmap_bus,
+ sx150x, &sx150x_regmap_config);
+ sx150x->client = client;
+ sx150x->data = data;
+ sx150x->gpio.ops = &sx150x_gpio_ops;
+ sx150x->gpio.base = -1;
+ sx150x->gpio.ngpio = sx150x->data->ngpios;
+ sx150x->gpio.dev = &client->dev;
+
+ return gpiochip_add(&sx150x->gpio);
+}
+
+static __maybe_unused struct of_device_id sx150x_dt_ids[] = {
+ { .compatible = "semtech,sx1503q", .data = &sx1503q_device_data, },
+ { }
+};
+
+static struct driver_d sx150x_driver = {
+ .name = "sx150x",
+ .probe = sx150x_probe,
+ .of_compatible = sx150x_dt_ids,
+};
+
+static int __init sx150x_init(void)
+{
+ return i2c_driver_register(&sx150x_driver);
+}
+device_initcall(sx150x_init);
--
2.5.5
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