On 10.04.2017 22:04, Linus Walleij wrote:
On Wed, Apr 5, 2017 at 3:07 PM, <michael.hennerich@xxxxxxxxxx> wrote:
From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
This patch adds support for the Analog Devices / Linear Technology
LTC4306 and LTC4305 4/2 Channel I2C Bus Multiplexer/Switches.
The LTC4306 optionally provides two general purpose input/output pins
(GPIOs) that can be configured as logic inputs, opendrain outputs or
push-pull outputs via the generic GPIOLIB framework.
Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Okay!
Hi Linus,
Thanks for your review.
Comments below.
+#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/driver.h>
Why are you including all these?
Normally a GPIO driver should just include
<linux/gpio/driver.h>
Well - this driver is also a gpio consumer.
But right I can drop gpio.h, and while gpio/driver.h also includes
device.h - we don't need it here as well.
+#include <linux/i2c-mux.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+static int ltc4306_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct ltc4306 *data = gpiochip_get_data(chip);
+ unsigned int val;
+ int ret;
+
+ ret = regmap_read(data->regmap, LTC_REG_CONFIG, &val);
+ if (ret < 0)
+ return ret;
+
+ return (val & BIT(1 - offset));
Do this:
return !!(val & BIT(1 - offset));
So you clamp the return value to [0,1]
That's what I had in a previous version of the patch.
Then I noticed gpiolib is also doing this.
Anyways I'll add it back.
+static int ltc4306_gpio_set_config(struct gpio_chip *chip,
+ unsigned int offset, unsigned long config)
+{
+ struct ltc4306 *data = gpiochip_get_data(chip);
+ unsigned int val;
+
+ switch (pinconf_to_config_param(config)) {
+ case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+ val = 0;
+ break;
+ case PIN_CONFIG_DRIVE_PUSH_PULL:
+ val = BIT(4 - offset);
+ break;
+ default:
+ return -ENOTSUPP;
+ }
+
+ return regmap_update_bits(data->regmap, LTC_REG_MODE,
+ BIT(4 - offset), val);
+}
Nice!
+ data->gpiochip.label = dev_name(dev);
+ data->gpiochip.base = -1;
+ data->gpiochip.ngpio = data->chip->num_gpios;
+ data->gpiochip.parent = dev;
+ data->gpiochip.can_sleep = true;
+ data->gpiochip.direction_input = ltc4306_gpio_direction_input;
+ data->gpiochip.direction_output = ltc4306_gpio_direction_output;
+ data->gpiochip.get = ltc4306_gpio_get;
+ data->gpiochip.set = ltc4306_gpio_set;
+ data->gpiochip.set_config = ltc4306_gpio_set_config;
+ data->gpiochip.owner = THIS_MODULE;
Please implement .get_direction().
This is very helpful to userspace, have you tested to use tools/gpio/*
from the kernel? Like lsgpio?
Ok - convinced me.
Yours,
Linus Walleij
--
Greetings,
Michael
--
Analog Devices GmbH Otl-Aicher Strasse 60-64 80807 München
Sitz der Gesellschaft München, Registergericht München HRB 40368,
Geschäftsführer: Peter Kolberg, Ali Raza Husain, Eileen Wynne
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
