The PCA9621 is an I2C 8-bit output open-drain expander. The driver has to be adapted to support open-drain outputs as the register bit values are inverted compared to currently supported chips.
Signed-off-by: Laurent Pinchart <[email protected]> --- drivers/gpio/gpio-pcf857x.c | 41 ++++++++++++++++++++++++++++++++++++----- 1 file changed, 36 insertions(+), 5 deletions(-) diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c index 404f3c61ef9b..24788f2da93b 100644 --- a/drivers/gpio/gpio-pcf857x.c +++ b/drivers/gpio/gpio-pcf857x.c @@ -31,6 +31,9 @@ #include <linux/slab.h> #include <linux/spinlock.h> +#define PCF857X_FLAG_OPEN_DRAIN (1 << 8) +#define PCF857X_FLAGS_MASK (0xff << 8) +#define PCF857X_INPUTS_MASK 0xff static const struct i2c_device_id pcf857x_id[] = { { "pcf8574", 8 }, @@ -41,6 +44,7 @@ static const struct i2c_device_id pcf857x_id[] = { { "pca9674", 8 }, { "pcf8575", 16 }, { "pca8575", 16 }, + { "pca9621", 8 | OPEN_DRAIN }, { "pca9671", 16 }, { "pca9673", 16 }, { "pca9675", 16 }, @@ -56,6 +60,7 @@ static const struct of_device_id pcf857x_of_table[] = { { .compatible = "nxp,pcf8574" }, { .compatible = "nxp,pcf8574a" }, { .compatible = "nxp,pca8574" }, + { .compatible = "nxp,pca9621" }, { .compatible = "nxp,pca9670" }, { .compatible = "nxp,pca9672" }, { .compatible = "nxp,pca9674" }, @@ -93,6 +98,7 @@ struct pcf857x { unsigned status; /* current status */ unsigned int irq_parent; unsigned irq_enabled; /* enabled irqs */ + unsigned flags; int (*write)(struct i2c_client *client, unsigned data); int (*read)(struct i2c_client *client); @@ -142,7 +148,10 @@ static int pcf857x_input(struct gpio_chip *chip, unsigned offset) int status; mutex_lock(&gpio->lock); - gpio->out |= (1 << offset); + if (gpio->flags & PCF857X_FLAG_OPEN_DRAIN) + gpio->out &= ~(1 << offset); + else + gpio->out |= (1 << offset); status = gpio->write(gpio->client, gpio->out); mutex_unlock(&gpio->lock); @@ -155,7 +164,13 @@ static int pcf857x_get(struct gpio_chip *chip, unsigned offset) int value; value = gpio->read(gpio->client); - return (value < 0) ? 0 : (value & (1 << offset)); + if (value < 0) + return 0; + + if (gpio->flags & PCF857X_FLAG_OPEN_DRAIN) + return !(value & (1 << offset)); + else + return value & (1 << offset); } static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value) @@ -164,6 +179,17 @@ static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value) unsigned bit = 1 << offset; int status; + if (gpio->flags & PCF857X_FLAG_OPEN_DRAIN) { + /* The output is open-drain and can't be driven high. */ + if (value) + return -EINVAL; + + /* To set the direction to output the register value has to be + * set to 1. + */ + value = 1; + } + mutex_lock(&gpio->lock); if (value) gpio->out |= bit; @@ -295,6 +321,8 @@ static int pcf857x_probe(struct i2c_client *client, mutex_init(&gpio->lock); spin_lock_init(&gpio->slock); + gpio->flags = id->driver_data & PCF857X_FLAGS_MASK; + gpio->chip.base = pdata ? pdata->gpio_base : -1; gpio->chip.can_sleep = true; gpio->chip.dev = &client->dev; @@ -303,7 +331,7 @@ static int pcf857x_probe(struct i2c_client *client, gpio->chip.set = pcf857x_set; gpio->chip.direction_input = pcf857x_input; gpio->chip.direction_output = pcf857x_output; - gpio->chip.ngpio = id->driver_data; + gpio->chip.ngpio = id->driver_data & PCF857X_INPUTS_MASK; /* NOTE: the OnSemi jlc1562b is also largely compatible with * these parts, notably for output. It has a low-resolution @@ -321,12 +349,15 @@ static int pcf857x_probe(struct i2c_client *client, gpio->read = i2c_read_le8; if (!i2c_check_functionality(client->adapter, - I2C_FUNC_SMBUS_BYTE)) + I2C_FUNC_SMBUS_BYTE)) { status = -EIO; /* fail if there's no chip present */ - else + } else { status = i2c_smbus_read_byte(client); + if (gpio->flags & PCF857X_FLAG_OPEN_DRAIN) + n_latch = status; + } /* '75/'75c addresses are 0x20..0x27, just like the '74; * the '75c doesn't have a current source pulling high. -- 2.4.9 -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
