śr., 18 mar 2020 o 13:45 Michael Walle <michael@xxxxxxxx> napisał(a):
>
> Hi Bartosz,
>
> Am 2020-03-18 10:14, schrieb Bartosz Golaszewski:
> > wt., 17 mar 2020 o 21:50 Michael Walle <michael@xxxxxxxx> napisał(a):
> >>
> >> This adds support for the GPIO controller of the sl28 board management
> >> controller. This driver is part of a multi-function device.
> >>
> >> Signed-off-by: Michael Walle <michael@xxxxxxxx>
> >
> > Hi Michael,
> >
> > thanks for the driver. Please take a look at some comments below.
>
> well, thank you for the very fast review!
>
> >> ---
> >> drivers/gpio/Kconfig | 11 ++
> >> drivers/gpio/Makefile | 1 +
> >> drivers/gpio/gpio-sl28cpld.c | 332
> >> +++++++++++++++++++++++++++++++++++
> >> 3 files changed, 344 insertions(+)
> >> create mode 100644 drivers/gpio/gpio-sl28cpld.c
> >>
> >> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> >> index 3cbf8882a0dd..516e47017ef5 100644
> >> --- a/drivers/gpio/Kconfig
> >> +++ b/drivers/gpio/Kconfig
> >> @@ -1211,6 +1211,17 @@ config GPIO_RC5T583
> >> This driver provides the support for driving/reading the
> >> gpio pins
> >> of RC5T583 device through standard gpio library.
> >>
> >> +config GPIO_SL28CPLD
> >> + tristate "Kontron sl28 GPIO"
> >> + depends on MFD_SL28CPLD
> >> + depends on OF_GPIO
> >> + select GPIOLIB_IRQCHIP
> >
> > Please see below - I think both are not needed.
> >
> >> + help
> >> + This enables support for the GPIOs found on the Kontron sl28
> >> CPLD.
> >> +
> >> + This driver can also be built as a module. If so, the module
> >> will be
> >> + called gpio-sl28cpld.
> >> +
> >> config GPIO_STMPE
> >> bool "STMPE GPIOs"
> >> depends on MFD_STMPE
> >> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> >> index 0b571264ddbc..0ca2d52c78e8 100644
> >> --- a/drivers/gpio/Makefile
> >> +++ b/drivers/gpio/Makefile
> >> @@ -127,6 +127,7 @@ obj-$(CONFIG_GPIO_SCH311X) +=
> >> gpio-sch311x.o
> >> obj-$(CONFIG_GPIO_SCH) += gpio-sch.o
> >> obj-$(CONFIG_GPIO_SIFIVE) += gpio-sifive.o
> >> obj-$(CONFIG_GPIO_SIOX) += gpio-siox.o
> >> +obj-$(CONFIG_GPIO_SL28CPLD) += gpio-sl28cpld.o
> >> obj-$(CONFIG_GPIO_SODAVILLE) += gpio-sodaville.o
> >> obj-$(CONFIG_GPIO_SPEAR_SPICS) += gpio-spear-spics.o
> >> obj-$(CONFIG_GPIO_SPRD) += gpio-sprd.o
> >> diff --git a/drivers/gpio/gpio-sl28cpld.c
> >> b/drivers/gpio/gpio-sl28cpld.c
> >> new file mode 100644
> >> index 000000000000..94f82013882f
> >> --- /dev/null
> >> +++ b/drivers/gpio/gpio-sl28cpld.c
> >> @@ -0,0 +1,332 @@
> >> +// SPDX-License-Identifier: GPL-2.0-only
> >> +/*
> >> + * SMARC-sAL28 GPIO driver.
> >> + *
> >> + * Copyright 2019 Kontron Europe GmbH
> >> + */
> >> +
> >> +#include <linux/kernel.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/regmap.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/gpio/driver.h>
> >> +
> >> +#define GPIO_REG_DIR 0
> >> +#define GPIO_REG_OUT 1
> >> +#define GPIO_REG_IN 2
> >> +#define GPIO_REG_IE 3
> >> +#define GPIO_REG_IP 4
> >
> > These values would be more clear if they were defined as hex.
> >
> >> +
> >> +#define GPI_REG_IN 0
> >> +
> >> +#define GPO_REG_OUT 0
> >
> > Please also use a common prefix even for defines.
>
> ok
>
> >
> >> +
> >> +enum sl28cpld_gpio_type {
> >> + sl28cpld_gpio,
> >> + sl28cpld_gpi,
> >> + sl28cpld_gpo,
> >> +};
> >
> > Enum values should be all upper-case.
>
> ok
>
> >> +
> >> +struct sl28cpld_gpio {
> >> + struct gpio_chip gpio_chip;
> >> + struct irq_chip irq_chip;
> >> + struct regmap *regmap;
> >> + u32 offset;
> >> + struct mutex lock;
> >> + u8 ie;
> >> +};
> >> +
> >> +static void sl28cpld_gpio_set_reg(struct gpio_chip *chip, unsigned
> >> int reg,
> >> + unsigned int offset, int value)
> >> +{
> >> + struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
> >> + unsigned int mask = 1 << offset;
> >> + unsigned int val = value << offset;
> >> +
> >> + regmap_update_bits(gpio->regmap, gpio->offset + reg, mask,
> >> val);
> >> +}
> >> +
> >> +static void sl28cpld_gpio_set(struct gpio_chip *chip, unsigned int
> >> offset,
> >> + int value)
> >> +{
> >> + sl28cpld_gpio_set_reg(chip, GPIO_REG_OUT, offset, value);
> >> +}
> >> +
> >> +static void sl28cpld_gpo_set(struct gpio_chip *chip, unsigned int
> >> offset,
> >> + int value)
> >> +{
> >> + sl28cpld_gpio_set_reg(chip, GPO_REG_OUT, offset, value);
> >> +}
> >> +
> >> +static int sl28cpld_gpio_get_reg(struct gpio_chip *chip, unsigned int
> >> reg,
> >> + unsigned int offset)
> >> +{
> >> + struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
> >> + unsigned int mask = 1 << offset;
> >> + unsigned int val;
> >> + int ret;
> >> +
> >> + ret = regmap_read(gpio->regmap, gpio->offset + reg, &val);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + return (val & mask) ? 1 : 0;
> >> +}
> >> +
> >> +static int sl28cpld_gpio_get(struct gpio_chip *chip, unsigned int
> >> offset)
> >> +{
> >> + return sl28cpld_gpio_get_reg(chip, GPIO_REG_IN, offset);
> >> +}
> >> +
> >> +static int sl28cpld_gpi_get(struct gpio_chip *chip, unsigned int
> >> offset)
> >> +{
> >> + return sl28cpld_gpio_get_reg(chip, GPI_REG_IN, offset);
> >> +}
> >> +
> >> +static int sl28cpld_gpio_get_direction(struct gpio_chip *chip,
> >> + unsigned int offset)
> >> +{
> >> + struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
> >> + unsigned int reg;
> >> + int ret;
> >> +
> >> + ret = regmap_read(gpio->regmap, gpio->offset + GPIO_REG_DIR,
> >> ®);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + if (reg & (1 << offset))
> >> + return GPIO_LINE_DIRECTION_OUT;
> >> + else
> >> + return GPIO_LINE_DIRECTION_IN;
> >> +}
> >> +
> >> +static int sl28cpld_gpio_set_direction(struct gpio_chip *chip,
> >> + unsigned int offset,
> >> + bool output)
> >> +{
> >> + struct sl28cpld_gpio *gpio = gpiochip_get_data(chip);
> >> + unsigned int mask = 1 << offset;
> >> + unsigned int val = (output) ? mask : 0;
> >> +
> >> + return regmap_update_bits(gpio->regmap, gpio->offset +
> >> GPIO_REG_DIR,
> >> + mask, val);
> >> +
> >
> > Stray newline.
> ok
>
> >
> >> +}
> >> +
> >> +static int sl28cpld_gpio_direction_input(struct gpio_chip *chip,
> >> + unsigned int offset)
> >> +{
> >> + return sl28cpld_gpio_set_direction(chip, offset, false);
> >> +}
> >> +
> >> +static int sl28cpld_gpio_direction_output(struct gpio_chip *chip,
> >> + unsigned int offset, int
> >> value)
> >> +{
> >> + sl28cpld_gpio_set_reg(chip, GPIO_REG_OUT, offset, value);
> >> + return sl28cpld_gpio_set_direction(chip, offset, true);
> >> +}
> >> +
> >> +static void sl28cpld_gpio_irq_lock(struct irq_data *data)
> >> +{
> >> + struct sl28cpld_gpio *gpio =
> >> + gpiochip_get_data(irq_data_get_irq_chip_data(data));
> >> +
> >> + mutex_lock(&gpio->lock);
> >
> > How does that actually lock anything?
>
> TBH, I took that from gpio-pcf857x.c. But that
> (1) don't uses regmap
> (2) also uses that lock on other places.
>
> I'll dig deeper into that and try to understand why there is a lock at
> all and why this callback is actually called _irq_lock() because that
> made me wonder.
>
> > Regmap uses a different lock and
> > if you want to make sure nobody modifies the GPIO registers than you'd
> > need to use the same lock. Also: this looks a lot like a task for
> > regmap_irqchip - maybe you could use it here or in the core mfd
> > module?
>
> regmap_irqchip will register the interrupt controller on the device
> which owns the regmap, ie. the parent. So (1) the phandle would need to
> point to the parent device instead of the GPIO subnode and (2) I'm
> already using the regmap_irqchip for the interrupt controller. I don't
> know if you can actually have that multiple times.
>
> there was a discussion which might apply partly to (1):
> https://lore.kernel.org/patchwork/patch/802608/
>
In that case maybe you should use the disable_locking option in
regmap_config and provide your own callbacks that you can use in the
irqchip code too?
> >
> >> +}
> >> +
> >> +static void sl28cpld_gpio_irq_sync_unlock(struct irq_data *data)
> >> +{
> >> + struct sl28cpld_gpio *gpio =
> >> + gpiochip_get_data(irq_data_get_irq_chip_data(data));
> >> +
> >> + regmap_write(gpio->regmap, gpio->offset + GPIO_REG_IE,
> >> gpio->ie);
> >> + mutex_unlock(&gpio->lock);
> >> +}
> >> +
> >> +static void sl28cpld_gpio_irq_disable(struct irq_data *data)
> >> +{
> >> + struct sl28cpld_gpio *gpio =
> >> + gpiochip_get_data(irq_data_get_irq_chip_data(data));
> >> +
> >> + if (data->hwirq >= 8)
> >> + return;
> >> +
> >> + gpio->ie &= ~(1 << data->hwirq);
> >> +}
> >> +
> >> +static void sl28cpld_gpio_irq_enable(struct irq_data *data)
> >> +{
> >> + struct sl28cpld_gpio *gpio =
> >> + gpiochip_get_data(irq_data_get_irq_chip_data(data));
> >> +
> >> + if (data->hwirq >= 8)
> >> + return;
> >> +
> >> + gpio->ie |= (1 << data->hwirq);
> >> +}
> >> +
> >> +static int sl28cpld_gpio_irq_set_type(struct irq_data *data, unsigned
> >> int type)
> >> +{
> >> + /* only edge triggered interrupts on both edges are supported
> >> */
> >> + return (type == IRQ_TYPE_EDGE_BOTH) ? 0 : -EINVAL;
> >> +}
> >> +
> >> +static irqreturn_t sl28cpld_gpio_irq_thread(int irq, void *data)
> >> +{
> >> + struct sl28cpld_gpio *gpio = data;
> >> + unsigned int ip;
> >> + unsigned int virq;
> >> + int pin;
> >> + int ret;
> >> +
> >> + ret = regmap_read(gpio->regmap, gpio->offset + GPIO_REG_IP,
> >> &ip);
> >> + if (ret)
> >> + return IRQ_NONE;
> >> +
> >> + /* mask other pending interrupts which are not enabled */
> >> + ip &= gpio->ie;
> >> +
> >> + /* ack the interrupts */
> >> + regmap_write(gpio->regmap, gpio->offset + GPIO_REG_IP, ip);
> >> +
> >> + /* and handle them */
> >> + while (ip) {
> >> + pin = __ffs(ip);
> >> + ip &= ~BIT(pin);
> >> +
> >> + virq = irq_find_mapping(gpio->gpio_chip.irq.domain,
> >> pin);
> >> + if (virq)
> >> + handle_nested_irq(virq);
> >> + }
> >> +
> >> + return IRQ_HANDLED;
> >> +}
> >
> > This definitely looks like parts of regmap_irqchip reimplemented.
> > Please check if you could reuse it - it would save a lot of code.
>
> See above. I'd be happy to reuse the code though.
>
> >
> >> +
> >> +static int sl28_cpld_gpio_irq_init(struct platform_device *pdev, int
> >> irq)
> >> +{
> >> + struct sl28cpld_gpio *gpio = platform_get_drvdata(pdev);
> >> + struct irq_chip *irq_chip = &gpio->irq_chip;
> >> + int ret;
> >> +
> >> + irq_chip->name = "sl28cpld-gpio-irq",
> >> + irq_chip->irq_bus_lock = sl28cpld_gpio_irq_lock,
> >> + irq_chip->irq_bus_sync_unlock = sl28cpld_gpio_irq_sync_unlock,
> >> + irq_chip->irq_disable = sl28cpld_gpio_irq_disable,
> >> + irq_chip->irq_enable = sl28cpld_gpio_irq_enable,
> >> + irq_chip->irq_set_type = sl28cpld_gpio_irq_set_type,
> >> + irq_chip->flags = IRQCHIP_SKIP_SET_WAKE,
> >> +
> >> + ret = gpiochip_irqchip_add_nested(&gpio->gpio_chip, irq_chip,
> >> 0,
> >> + handle_simple_irq,
> >> IRQ_TYPE_NONE);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> >> + sl28cpld_gpio_irq_thread,
> >> + IRQF_SHARED | IRQF_ONESHOT,
> >> + pdev->name, gpio);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + gpiochip_set_nested_irqchip(&gpio->gpio_chip, irq_chip, irq);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int sl28cpld_gpio_probe(struct platform_device *pdev)
> >> +{
> >> + enum sl28cpld_gpio_type type =
> >> + platform_get_device_id(pdev)->driver_data;
> >> + struct device_node *np = pdev->dev.of_node;
> >> + struct sl28cpld_gpio *gpio;
> >> + struct gpio_chip *chip;
> >> + struct resource *res;
> >> + bool irq_support = false;
> >> + int ret;
> >> + int irq;
> >> +
> >> + gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
> >> + if (!gpio)
> >> + return -ENOMEM;
> >> +
> >> + if (!pdev->dev.parent)
> >> + return -ENODEV;
> >
> > Why not check this before allocating any memory?
>
> I'll change that, you're not the first one which notices that. My reason
> was to have the check together with the dev_get_regmap() which uses the
> parent, expecting that the error case only happen exceptionally.
>
> >
> >> +
> >> + gpio->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> >> + if (!gpio->regmap)
> >> + return -ENODEV;
> >> +
> >> + res = platform_get_resource(pdev, IORESOURCE_REG, 0);
> >> + if (!res)
> >> + return -EINVAL;
> >> + gpio->offset = res->start;
> >> +
> >
> > This isn't how IO resources are used. What are you trying to achieve
> > here?
>
> Mh are you sure? The blueprint for this were the regulators in
> drivers/regulators/, eg the wm831x-ldo.c. IORESOURCE_REG isn't used
> that often. But here is what I want to achieve (for which I haven't
> found any existing drivers for now):
> (1) the individual blocks of the overall sl28cpld may be used
> multiple times, eg. this driver only has the offset to a
> base address. So if there are two blocks, this mfd core
> driver will register two devices for this driver with
> different base offsets, which are passed by IORESOURCE_REG
> (2) I wanted to avoid having a private mfd include with some
> kind of "proprietary" method how to get that offset
> (3) the mfd core driver is the one knowing the offset, thus it
> is possible to have different flavours of the sl28cpld
>
Ok, now I see it's documented in the bindings. Thanks for the explanation.
>
> >
> >> + /* initialize struct gpio_chip */
> >> + mutex_init(&gpio->lock);
> >> + chip = &gpio->gpio_chip;
> >> + chip->parent = &pdev->dev;
> >> + chip->label = dev_name(&pdev->dev);
> >> + chip->owner = THIS_MODULE;
> >> + chip->can_sleep = true;
> >> + chip->base = -1;
> >> + chip->ngpio = 8;
> >> +
> >> + switch (type) {
> >> + case sl28cpld_gpio:
> >> + chip->get_direction = sl28cpld_gpio_get_direction;
> >> + chip->direction_input = sl28cpld_gpio_direction_input;
> >> + chip->direction_output =
> >> sl28cpld_gpio_direction_output;
> >> + chip->get = sl28cpld_gpio_get;
> >> + chip->set = sl28cpld_gpio_set;
> >> + irq_support = true;
> >> + break;
> >> + case sl28cpld_gpo:
> >> + chip->set = sl28cpld_gpo_set;
> >> + chip->get = sl28cpld_gpi_get;
> >> + break;
> >> + case sl28cpld_gpi:
> >> + chip->get = sl28cpld_gpi_get;
> >> + break;
> >> + }
> >> +
> >> + ret = devm_gpiochip_add_data(&pdev->dev, chip, gpio);
> >> + if (ret < 0)
> >> + return ret;
> >> +
> >> + platform_set_drvdata(pdev, gpio);
> >> +
> >> + if (irq_support && of_property_read_bool(np,
> >> "interrupt-controller")) {
> >
> > You're depending on OF_GPIO for this one function. Please switch to
> > device_property_read_bool() instead.
>
> ok
>
>
> >
> >> + irq = platform_get_irq(pdev, 0);
> >> + if (irq < 0)
> >> + return ret;
> >> +
> >> + ret = sl28_cpld_gpio_irq_init(pdev, irq);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static const struct platform_device_id sl28cpld_gpio_id_table[] = {
> >> + {"sl28cpld-gpio", sl28cpld_gpio},
> >> + {"sl28cpld-gpi", sl28cpld_gpi},
> >> + {"sl28cpld-gpo", sl28cpld_gpo},
> >
> > Could you explain this a bit more? Is this the same component with
> > input/output-only lines or three different components?
>
> These are actually three different components. Ie. you could have a
> flavour where you have one GPIO (sl28cpld-gpio) and two output-only
> ones (sl28cpld-gpo). Is that what you wanted to know?
>
Yes, thanks. This could use some documentation in the bindings though.
Bartosz
> >
> >> +};
> >> +MODULE_DEVICE_TABLE(platform, sl28cpld_gpio_id_table);
> >> +
> >> +static struct platform_driver sl28cpld_gpio_driver = {
> >> + .probe = sl28cpld_gpio_probe,
> >> + .id_table = sl28cpld_gpio_id_table,
> >> + .driver = {
> >> + .name = "sl28cpld-gpio",
> >> + },
> >> +};
> >> +module_platform_driver(sl28cpld_gpio_driver);
> >> +
> >> +MODULE_DESCRIPTION("sl28cpld GPIO Driver");
> >> +MODULE_LICENSE("GPL");
> >
> > I think you could use a MODULE_ALIAS() here if you want this module to
> > be loaded automatically by udev.
>
> ok, I'll look into that.
>
> thanks,
> -michael
>
> >
> >> --
> >> 2.20.1
> >>
> >
> > Best regards,
> > Bartosz Golaszewski
