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Date: Sat, 21 Jan 2017 00:02:53 +0200
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jslaby@...e.com>,
One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>
Subject: Re: [PATCH v10 1/3] gpio: exar: add gpio for exar cards
On Fri, Jan 20, 2017 at 12:23 AM, Sudip Mukherjee
<sudipm.mukherjee@...il.com> wrote:
> From: Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>
>
> Exar XR17V352/354/358 chips have 16 multi-purpose inputs/outputs which
> can be controlled using gpio interface.
>
> Add the gpio specific code.
>
Looks nice and clean!
FWIW:
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>
> ---
> drivers/gpio/Kconfig | 7 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-exar.c | 200 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 208 insertions(+)
> create mode 100644 drivers/gpio/gpio-exar.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index ed37e59..89033d6 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -185,6 +185,13 @@ config GPIO_ETRAXFS
> help
> Say yes here to support the GPIO controller on Axis ETRAX FS SoCs.
>
> +config GPIO_EXAR
> + tristate "Support for GPIO pins on XR17V352/354/358"
> + depends on SERIAL_8250_EXAR
> + help
> + Selecting this option will enable handling of GPIO pins present
> + on Exar XR17V352/354/358 chips.
> +
> config GPIO_GE_FPGA
> bool "GE FPGA based GPIO"
> depends on GE_FPGA
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index d074c22..d4d44f8 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -44,6 +44,7 @@ obj-$(CONFIG_GPIO_DWAPB) += gpio-dwapb.o
> obj-$(CONFIG_GPIO_EM) += gpio-em.o
> obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o
> obj-$(CONFIG_GPIO_ETRAXFS) += gpio-etraxfs.o
> +obj-$(CONFIG_GPIO_EXAR) += gpio-exar.o
> obj-$(CONFIG_GPIO_F7188X) += gpio-f7188x.o
> obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o
> obj-$(CONFIG_GPIO_GPIO_MM) += gpio-gpio-mm.o
> diff --git a/drivers/gpio/gpio-exar.c b/drivers/gpio/gpio-exar.c
> new file mode 100644
> index 0000000..05c8946
> --- /dev/null
> +++ b/drivers/gpio/gpio-exar.c
> @@ -0,0 +1,200 @@
> +/*
> + * GPIO driver for Exar XR17V35X chip
> + *
> + * Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>
> + *
> + * 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.
> + */
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +
> +#define EXAR_OFFSET_MPIOLVL_LO 0x90
> +#define EXAR_OFFSET_MPIOSEL_LO 0x93
> +#define EXAR_OFFSET_MPIOLVL_HI 0x96
> +#define EXAR_OFFSET_MPIOSEL_HI 0x99
> +
> +#define DRIVER_NAME "gpio_exar"
> +
> +static DEFINE_IDA(ida_index);
> +
> +struct exar_gpio_chip {
> + struct gpio_chip gpio_chip;
> + struct mutex lock;
> + int index;
> + void __iomem *regs;
> + char name[20];
> +};
> +
> +static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
> + unsigned int offset)
> +{
> + struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
> + int temp;
> +
> + mutex_lock(&exar_gpio->lock);
> + temp = readb(exar_gpio->regs + reg);
> + temp &= ~BIT(offset);
> + if (val)
> + temp |= BIT(offset);
> + writeb(temp, exar_gpio->regs + reg);
> + mutex_unlock(&exar_gpio->lock);
> +}
> +
> +static int exar_set_direction(struct gpio_chip *chip, int direction,
> + unsigned int offset)
> +{
> + unsigned int bank = offset / 8;
> + unsigned int addr;
> +
> + addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
> + exar_update(chip, addr, direction, offset % 8);
> + return 0;
> +}
> +
> +static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + return exar_set_direction(chip, 0, offset);
> +}
> +
> +static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
> +{
> + return exar_set_direction(chip, 1, offset);
> +}
> +
> +static int exar_get(struct gpio_chip *chip, unsigned int reg)
> +{
> + struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
> + int value;
> +
> + mutex_lock(&exar_gpio->lock);
> + value = readb(exar_gpio->regs + reg);
> + mutex_unlock(&exar_gpio->lock);
> +
> + return !!value;
> +}
> +
> +static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
> +{
> + unsigned int bank = offset / 8;
> + unsigned int addr;
> + int val;
> +
> + addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
> + val = exar_get(chip, addr) >> (offset % 8);
> +
> + return !!val;
> +}
> +
> +static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
> +{
> + unsigned int bank = offset / 8;
> + unsigned int addr;
> + int val;
> +
> + addr = bank ? EXAR_OFFSET_MPIOLVL_LO : EXAR_OFFSET_MPIOLVL_HI;
> + val = exar_get(chip, addr) >> (offset % 8);
> +
> + return !!val;
> +}
> +
> +static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
> + int value)
> +{
> + unsigned int bank = offset / 8;
> + unsigned int addr;
> +
> + addr = bank ? EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
> + exar_update(chip, addr, value, offset % 8);
> +}
> +
> +static int gpio_exar_probe(struct platform_device *pdev)
> +{
> + struct pci_dev *pcidev = platform_get_drvdata(pdev);
> + struct exar_gpio_chip *exar_gpio;
> + void __iomem *p;
> + int index, ret;
> +
> + if (pcidev->vendor != PCI_VENDOR_ID_EXAR)
> + return -ENODEV;
> +
> + /*
> + * Map the pci device to get the register addresses.
> + * We will need to read and write those registers to control
> + * the GPIO pins.
> + * Using managed functions will save us from unmaping on exit.
> + * As the device is enabled using managed functions by the
> + * UART driver we can also use managed functions here.
> + */
> + p = pcim_iomap(pcidev, 0, 0);
> + if (!p)
> + return -ENOMEM;
> +
> + exar_gpio = devm_kzalloc(&pcidev->dev, sizeof(*exar_gpio), GFP_KERNEL);
> + if (!exar_gpio)
> + return -ENOMEM;
> +
> + mutex_init(&exar_gpio->lock);
> +
> + index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
> +
> + sprintf(exar_gpio->name, "exar_gpio%d", index);
> + exar_gpio->gpio_chip.label = exar_gpio->name;
> + exar_gpio->gpio_chip.parent = &pcidev->dev;
> + exar_gpio->gpio_chip.direction_output = exar_direction_output;
> + exar_gpio->gpio_chip.direction_input = exar_direction_input;
> + exar_gpio->gpio_chip.get_direction = exar_get_direction;
> + exar_gpio->gpio_chip.get = exar_get_value;
> + exar_gpio->gpio_chip.set = exar_set_value;
> + exar_gpio->gpio_chip.base = -1;
> + exar_gpio->gpio_chip.ngpio = 16;
> + exar_gpio->regs = p;
> + exar_gpio->index = index;
> +
> + ret = devm_gpiochip_add_data(&pcidev->dev,
> + &exar_gpio->gpio_chip, exar_gpio);
> + if (ret)
> + goto err_destroy;
> +
> + platform_set_drvdata(pdev, exar_gpio);
> +
> + return 0;
> +
> +err_destroy:
> + ida_simple_remove(&ida_index, index);
> + mutex_destroy(&exar_gpio->lock);
> + return ret;
> +}
> +
> +static int gpio_exar_remove(struct platform_device *pdev)
> +{
> + struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev);
> +
> + ida_simple_remove(&ida_index, exar_gpio->index);
> + mutex_destroy(&exar_gpio->lock);
> +
> + return 0;
> +}
> +
> +static struct platform_driver gpio_exar_driver = {
> + .probe = gpio_exar_probe,
> + .remove = gpio_exar_remove,
> + .driver = {
> + .name = DRIVER_NAME,
> + },
> +};
> +
> +module_platform_driver(gpio_exar_driver);
> +
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> +MODULE_DESCRIPTION("Exar GPIO driver");
> +MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>");
> +MODULE_LICENSE("GPL");
> --
> 1.9.1
>
--
With Best Regards,
Andy Shevchenko
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