On 12/11/2014 08:28 AM, Sergei Shtylyov wrote:
> MAX3355E chip integrates a charge pump and comparators to enable a system with
> an integrated USB OTG dual-role transceiver to function as a USB OTG dual-role
> device. In addition to sensing/controlling Vbus, the chip also passes thru the
> ID signal from the USB OTG connector. On some Renesas boards, this signal is
> just fed into the SoC thru a GPIO pin -- there's no real OTG controller, only
> host and gadget USB controllers sharing the same USB bus; however, we'd like
> to allow host or gadget drivers to be loaded depending on the cable type, hence
> the need for the MAX3355 extcon driver. The Vbus status signals are also wired
> to GPIOs (however, we're not currently intested in them), the OFFVBUS# signal
> is controlled by the host controllers, there's also the SHDN# signal wired to
> GPIO, which should be high for normal operation.
>
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
>
> ---
> The patch is against the 'extcon-next' branch of the 'extcon.git' repo.
>
> Documentation/devicetree/bindings/extcon/extcon-max3355.txt | 21 ++
> drivers/extcon/Kconfig | 6
> drivers/extcon/Makefile | 1
> drivers/extcon/extcon-max3355.c | 122 ++++++++++++
> 4 files changed, 150 insertions(+)
>
> Index: extcon/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> ===================================================================
> --- /dev/null
> +++ extcon/Documentation/devicetree/bindings/extcon/extcon-max3355.txt
> @@ -0,0 +1,21 @@
> +MAX3355 USB OTG chip
Need manufactor information as following :
-> Maxim MAX3355
> +--------------------
> +
> +MAX3355 integrates a charge pump and comparators to enable a system with an
> +integrated USB OTG dual-role transceiver to function as a USB OTG dual-role
> +device.
> +
> +Required properties:
> +- compatible: should be "maxim,max3355";
> +- maxim,shdn-gpio: should contain a phandle and GPIO specifier for the GPIO pin
> + connected to the MAX3355's SHDN# pin;
> +- maxim,id-gpio: should contain a phandle and GPIO specifier for the GPIO pin
> + connected to the MAX3355's ID_OUT pin.
> +
> +Example (Koelsch board):
> +
> + usb-otg {
> + compatible = "maxim,max3355";
> + maxim,shdn-gpio = <&gpio2 4 GPIO_ACTIVE_LOW>;
> + maxim,id-gpio = <&gpio5 31 GPIO_ACTIVE_HIGH>;
Kernel already supported the gpio helper function to get gpio from devicetree.
I prefer use follwoing style by using of_get_gpio()/of_get_gpio_flags() in include/linux/of_gpio.h.
gpios = <&gpio2 4 GPIO_ACTIVE_LOW>, <&gpio5 31 GPIO_ACTIVE_HIGH>;
> + };
> Index: extcon/drivers/extcon/Kconfig
> ===================================================================
> --- extcon.orig/drivers/extcon/Kconfig
> +++ extcon/drivers/extcon/Kconfig
> @@ -45,6 +45,12 @@ config EXTCON_MAX14577
> Maxim MAX14577/77836. The MAX14577/77836 MUIC is a USB port accessory
> detector and switch.
>
> +config EXTCON_MAX3355
> + tristate "MAX3355 USB OTG EXTCON Support"
> + help
> + Say Y here to enable support for the USB host detection by MAX3355
> + OTG USB chip.
> +
> config EXTCON_MAX77693
> tristate "MAX77693 EXTCON Support"
> depends on MFD_MAX77693 && INPUT
> Index: extcon/drivers/extcon/Makefile
> ===================================================================
> --- extcon.orig/drivers/extcon/Makefile
> +++ extcon/drivers/extcon/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_EXTCON_ADC_JACK) += extcon-
> obj-$(CONFIG_EXTCON_ARIZONA) += extcon-arizona.o
> obj-$(CONFIG_EXTCON_GPIO) += extcon-gpio.o
> obj-$(CONFIG_EXTCON_MAX14577) += extcon-max14577.o
> +obj-$(CONFIG_EXTCON_MAX3355) += extcon-max3355.o
> obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o
> obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o
> obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o
> Index: extcon/drivers/extcon/extcon-max3355.c
> ===================================================================
> --- /dev/null
> +++ extcon/drivers/extcon/extcon-max3355.c
> @@ -0,0 +1,122 @@
> +/*
> + * MAX3355 USB OTG chip extcon driver
ditto.
> + *
> + * Copyright (C) 2014 Cogent Embedded, Inc.
> + * Author: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + */
> +
> +#include <linux/extcon.h>
> +#include <linux/gpio.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +
> +struct max3355_data {
> + struct extcon_dev *edev;
> + int id_gpio;
> +};
> +
> +static const char *max3355_cable[] = {
> + [0] = "USB-HOST",
> + NULL,
> +};
> +
> +static irqreturn_t max3355_id_irq(int irq, void *dev_id)
> +{
> + struct max3355_data *data = dev_id;
> + int id = gpio_get_value(data->id_gpio);
> +
> + extcon_set_cable_state(data->edev, "USB-HOST", !id);
You have to get the gpio flag in the devicetree by using of_get_gpio_flags() function
and then you would set the cable state according to gpio state and flag.
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int max3355_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct max3355_data *data;
> + int gpio, irq, ret;
> +
> + data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
> + GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
> + if (IS_ERR(data->edev)) {
> + dev_err(&pdev->dev, "failed to allocate extcon device\n");
> + return PTR_ERR(data->edev);
> + }
> + data->edev->name = kstrdup(np->name, GFP_KERNEL);
> +
> + gpio = of_get_named_gpio(np, "maxim,id-gpio", 0);
Use of_get_gpio() or of_get_gpio_flags().
"maxim,id-gpio" property has strong dependency on this driver and it is not standard.
> + if (gpio < 0)
> + return gpio;
Need to add error message.
> + data->id_gpio = gpio;
> +
> + gpio = of_get_named_gpio(np, "maxim,shdn-gpio", 0);
ditto.
> + if (gpio < 0)
> + return gpio;
Need to add error message.
> +
> + ret = devm_gpio_request_one(&pdev->dev, gpio, GPIOF_DIR_OUT |
> + GPIOF_INIT_HIGH, pdev->name);
> + if (ret < 0)
> + return ret;
Need to add error message.
> +
> + ret = devm_gpio_request_one(&pdev->dev, data->id_gpio, GPIOF_DIR_IN,
> + pdev->name);
Why do you use same name for two gpio when devm_gpio_request_one?
I prefer to use other name because two gpio is different.
> + if (ret < 0)
> + return ret;
> +
> + ret = devm_extcon_dev_register(&pdev->dev, data->edev);
> + if (ret < 0)
> + return ret;
Need to add error message.
> +
> + irq = gpio_to_irq(data->id_gpio);
> + if (irq < 0)
> + return irq;
Need to add error message.
> +
> + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, max3355_id_irq,
> + IRQF_TRIGGER_RISING |
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
Is it right to add both RISING and FALLING trigger?
and need to add IRQF_NO_SUSPEND to wakeup from suspend state when interrupt happen.
> + pdev->name, data);
> + if (ret < 0)
> + return ret;
Need to add error message.
> +
> + platform_set_drvdata(pdev, data);
> +
> + /* Perform initial detection */
> + max3355_id_irq(irq, data);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id max3355_match_table[] = {
> + { .compatible = "maxim,max3355", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, max3355_match_table);
> +
> +static struct platform_driver max3355_driver = {
> + .probe = max3355_probe,
> + .driver = {
> + .name = "extcon-max3355",
> + .of_match_table = max3355_match_table,
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +module_platform_driver(max3355_driver);
> +
Don't need un-used blank line.
> +MODULE_AUTHOR("Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("MAX3355 extcon driver");
Maxim MAX3355.
> +MODULE_LICENSE("GPL v2");
>
>
Thanks,
Chanwoo Choi
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