* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 5:58 ` [PATCH v2 1/2] gpio: Add gpio latch driver Sascha Hauer
@ 2022-08-31 8:01 ` Marco Felsch
2022-08-31 9:07 ` Sascha Hauer
2022-08-31 11:50 ` Bartosz Golaszewski
` (3 subsequent siblings)
4 siblings, 1 reply; 12+ messages in thread
From: Marco Felsch @ 2022-08-31 8:01 UTC (permalink / raw)
To: Sascha Hauer
Cc: linux-gpio, linux-kernel, Geert Uytterhoeven, kernel,
Bartosz Golaszewski, Linus Walleij
Hi Sascha,
On 22-08-31, Sascha Hauer wrote:
> This driver implements a GPIO multiplexer based on latches connected to
> other GPIOs. A set of data GPIOs is connected to the data input of
> multiple latches. The clock input of each latch is driven by another
> set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> are output only.
>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
apart the one minor nit (see end) feel free to add my
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
> drivers/gpio/Kconfig | 6 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-latch.c | 190 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 197 insertions(+)
> create mode 100644 drivers/gpio/gpio-latch.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 0642f579196f2..e4603810ec910 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -1690,6 +1690,12 @@ config GPIO_AGGREGATOR
> industrial control context, to be operated from userspace using
> the GPIO chardev interface.
>
> +config GPIO_LATCH
> + tristate "GPIO latch driver"
> + help
> + Say yes here to enable a driver for GPIO multiplexers based on latches
> + connected to other GPIOs.
> +
> config GPIO_MOCKUP
> tristate "GPIO Testing Driver"
> select IRQ_SIM
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index a0985d30f51bb..310fa08decc69 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -75,6 +75,7 @@ obj-$(CONFIG_GPIO_IT87) += gpio-it87.o
> obj-$(CONFIG_GPIO_IXP4XX) += gpio-ixp4xx.o
> obj-$(CONFIG_GPIO_JANZ_TTL) += gpio-janz-ttl.o
> obj-$(CONFIG_GPIO_KEMPLD) += gpio-kempld.o
> +obj-$(CONFIG_GPIO_LATCH) += gpio-latch.o
> obj-$(CONFIG_GPIO_LOGICVC) += gpio-logicvc.o
> obj-$(CONFIG_GPIO_LOONGSON1) += gpio-loongson1.o
> obj-$(CONFIG_GPIO_LOONGSON) += gpio-loongson.o
> diff --git a/drivers/gpio/gpio-latch.c b/drivers/gpio/gpio-latch.c
> new file mode 100644
> index 0000000000000..4068ed4066272
> --- /dev/null
> +++ b/drivers/gpio/gpio-latch.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * GPIO latch driver
> + *
> + * Copyright (C) 2022 Sascha Hauer <s.hauer@pengutronix.de>
> + *
> + * This driver implements a GPIO (or better GPO as there is no input)
> + * multiplexer based on latches like this:
> + *
> + * CLK0 ----------------------. ,--------.
> + * CLK1 -------------------. `--------|> #0 |
> + * | | |
> + * OUT0 ----------------+--|-----------|D0 Q0|-----|<
> + * OUT1 --------------+-|--|-----------|D1 Q1|-----|<
> + * OUT2 ------------+-|-|--|-----------|D2 Q2|-----|<
> + * OUT3 ----------+-|-|-|--|-----------|D3 Q3|-----|<
> + * OUT4 --------+-|-|-|-|--|-----------|D4 Q4|-----|<
> + * OUT5 ------+-|-|-|-|-|--|-----------|D5 Q5|-----|<
> + * OUT6 ----+-|-|-|-|-|-|--|-----------|D6 Q6|-----|<
> + * OUT7 --+-|-|-|-|-|-|-|--|-----------|D7 Q7|-----|<
> + * | | | | | | | | | `--------'
> + * | | | | | | | | |
> + * | | | | | | | | | ,--------.
> + * | | | | | | | | `-----------|> #1 |
> + * | | | | | | | | | |
> + * | | | | | | | `--------------|D0 Q0|-----|<
> + * | | | | | | `----------------|D1 Q1|-----|<
> + * | | | | | `------------------|D2 Q2|-----|<
> + * | | | | `--------------------|D3 Q3|-----|<
> + * | | | `----------------------|D4 Q4|-----|<
> + * | | `------------------------|D5 Q5|-----|<
> + * | `--------------------------|D6 Q6|-----|<
> + * `----------------------------|D7 Q7|-----|<
> + * `--------'
> + *
> + * The above is just an example. The actual number of number of latches and
> + * the number of inputs per latch is derived from the number of GPIOs given
> + * in the corresponding device tree properties.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio/consumer.h>
> +
> +#include "gpiolib.h"
> +
> +struct gpio_latch_priv {
> + struct gpio_chip gc;
> + struct gpio_descs *clk_gpios;
> + struct gpio_descs *data_gpios;
> + spinlock_t lock;
> + int n_ports;
> + int n_pins;
> + unsigned int *shadow;
> + struct mutex mutex;
> + spinlock_t spinlock;
> +};
> +
> +static int gpio_latch_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> + return GPIO_LINE_DIRECTION_OUT;
> +}
> +
> +static void __gpio_latch_set(struct gpio_latch_priv *priv,
> + void (* set)(struct gpio_desc *desc, int value),
> + unsigned int offset, int val)
> +{
> + int latch = offset / priv->n_pins;
> + int i;
> +
> + if (val)
> + priv->shadow[latch] |= BIT(offset % priv->n_pins);
> + else
> + priv->shadow[latch] &= ~BIT(offset % priv->n_pins);
> +
> + for (i = 0; i < priv->n_pins; i++)
> + set(priv->data_gpios->desc[i], priv->shadow[latch] & BIT(i));
> +
> + set(priv->clk_gpios->desc[latch], 1);
> + set(priv->clk_gpios->desc[latch], 0);
> +}
> +
> +static void gpio_latch_set(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + struct gpio_latch_priv *priv = gpiochip_get_data(gc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&priv->spinlock, flags);
> +
> + __gpio_latch_set(priv, gpiod_set_value, offset, val);
> +
> + spin_unlock_irqrestore(&priv->spinlock, flags);
> +}
> +
> +static void gpio_latch_set_can_sleep(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + struct gpio_latch_priv *priv = gpiochip_get_data(gc);
> +
> + mutex_lock(&priv->mutex);
> +
> + __gpio_latch_set(priv, gpiod_set_value_cansleep, offset, val);
> +
> + mutex_unlock(&priv->mutex);
> +}
> +
> +static bool gpio_latch_can_sleep(struct gpio_latch_priv *priv)
> +{
> + int i;
> +
> + for (i = 0; i < priv->n_ports; i++)
> + if (gpiod_cansleep(priv->clk_gpios->desc[i]))
> + return true;
> +
> + for (i = 0; i < priv->n_pins; i++)
> + if (gpiod_cansleep(priv->data_gpios->desc[i]))
> + return true;
> +
> + return false;
> +}
> +
> +static int gpio_latch_probe(struct platform_device *pdev)
> +{
> + struct gpio_latch_priv *priv;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->clk_gpios = devm_gpiod_get_array(&pdev->dev, "clk", GPIOD_OUT_LOW);
> + if (IS_ERR(priv->clk_gpios))
> + return PTR_ERR(priv->clk_gpios);
> +
> + priv->data_gpios = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_OUT_LOW);
> + if (IS_ERR(priv->data_gpios))
> + return PTR_ERR(priv->data_gpios);
> +
> + priv->n_ports = priv->clk_gpios->ndescs;
> + priv->n_pins = priv->data_gpios->ndescs;
> +
> + priv->shadow = devm_kcalloc(&pdev->dev, priv->n_ports, sizeof(*priv->shadow),
> + GFP_KERNEL);
> + if (!priv->shadow)
> + return -ENOMEM;
> +
> + if (gpio_latch_can_sleep(priv)) {
> + priv->gc.can_sleep = true;
> + priv->gc.set = gpio_latch_set_can_sleep;
> + mutex_init(&priv->mutex);
> + } else {
> + priv->gc.can_sleep = false;
> + priv->gc.set = gpio_latch_set;
> + spin_lock_init(&priv->spinlock);
> + }
> +
> + priv->gc.get_direction = gpio_latch_get_direction;
> + priv->gc.ngpio = priv->n_ports * priv->n_pins;
> + priv->gc.owner = THIS_MODULE;
> + priv->gc.base = -1;
> + priv->gc.parent = &pdev->dev;
> + priv->gc.of_node = pdev->dev.of_node;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
> +}
> +
> +static const struct of_device_id gpio_latch_ids[] = {
> + {
> + .compatible = "gpio-latch",
> + }, {
> + /* sentinel */
> + }
> +};
> +MODULE_DEVICE_TABLE(of, gpio_latch_ids);
> +
> +static struct platform_driver gpio_latch_driver = {
> + .driver = {
> + .name = "gpio-latch",
> + .of_match_table = gpio_latch_ids,
> + },
> + .probe = gpio_latch_probe,
> +};
> +module_platform_driver(gpio_latch_driver);
> +
> +MODULE_LICENSE("GPL v2");
checkpatch.pl should complain about this since it it now GPL, see commit
bf7fbeeae6db. Sorry for not spotted that earlier.
Regards,
Marco
> +MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
> +MODULE_DESCRIPTION("GPIO latch driver");
> --
> 2.30.2
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 8:01 ` Marco Felsch
@ 2022-08-31 9:07 ` Sascha Hauer
0 siblings, 0 replies; 12+ messages in thread
From: Sascha Hauer @ 2022-08-31 9:07 UTC (permalink / raw)
To: Marco Felsch
Cc: linux-gpio, linux-kernel, Geert Uytterhoeven, kernel,
Bartosz Golaszewski, Linus Walleij
On Wed, Aug 31, 2022 at 10:01:09AM +0200, Marco Felsch wrote:
> Hi Sascha,
>
> On 22-08-31, Sascha Hauer wrote:
> > This driver implements a GPIO multiplexer based on latches connected to
> > other GPIOs. A set of data GPIOs is connected to the data input of
> > multiple latches. The clock input of each latch is driven by another
> > set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> > 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> > are output only.
> >
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
>
> apart the one minor nit (see end) feel free to add my
>
> Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
>
> > +// SPDX-License-Identifier: GPL-2.0-or-later
[snip]
> > +MODULE_LICENSE("GPL v2");
>
> checkpatch.pl should complain about this since it it now GPL, see commit
> bf7fbeeae6db. Sorry for not spotted that earlier.
Just checked, checkpatch doesn't complain. Will fix in v3
Sascha
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 5:58 ` [PATCH v2 1/2] gpio: Add gpio latch driver Sascha Hauer
2022-08-31 8:01 ` Marco Felsch
@ 2022-08-31 11:50 ` Bartosz Golaszewski
2022-08-31 20:50 ` Andy Shevchenko
` (2 subsequent siblings)
4 siblings, 0 replies; 12+ messages in thread
From: Bartosz Golaszewski @ 2022-08-31 11:50 UTC (permalink / raw)
To: Sascha Hauer
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Sascha Hauer
On Wed, Aug 31, 2022 at 7:58 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
>
> This driver implements a GPIO multiplexer based on latches connected to
> other GPIOs. A set of data GPIOs is connected to the data input of
> multiple latches. The clock input of each latch is driven by another
> set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> are output only.
>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
> drivers/gpio/Kconfig | 6 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-latch.c | 190 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 197 insertions(+)
> create mode 100644 drivers/gpio/gpio-latch.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 0642f579196f2..e4603810ec910 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -1690,6 +1690,12 @@ config GPIO_AGGREGATOR
> industrial control context, to be operated from userspace using
> the GPIO chardev interface.
>
> +config GPIO_LATCH
> + tristate "GPIO latch driver"
> + help
> + Say yes here to enable a driver for GPIO multiplexers based on latches
> + connected to other GPIOs.
> +
> config GPIO_MOCKUP
> tristate "GPIO Testing Driver"
> select IRQ_SIM
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index a0985d30f51bb..310fa08decc69 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -75,6 +75,7 @@ obj-$(CONFIG_GPIO_IT87) += gpio-it87.o
> obj-$(CONFIG_GPIO_IXP4XX) += gpio-ixp4xx.o
> obj-$(CONFIG_GPIO_JANZ_TTL) += gpio-janz-ttl.o
> obj-$(CONFIG_GPIO_KEMPLD) += gpio-kempld.o
> +obj-$(CONFIG_GPIO_LATCH) += gpio-latch.o
> obj-$(CONFIG_GPIO_LOGICVC) += gpio-logicvc.o
> obj-$(CONFIG_GPIO_LOONGSON1) += gpio-loongson1.o
> obj-$(CONFIG_GPIO_LOONGSON) += gpio-loongson.o
> diff --git a/drivers/gpio/gpio-latch.c b/drivers/gpio/gpio-latch.c
> new file mode 100644
> index 0000000000000..4068ed4066272
> --- /dev/null
> +++ b/drivers/gpio/gpio-latch.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * GPIO latch driver
> + *
> + * Copyright (C) 2022 Sascha Hauer <s.hauer@pengutronix.de>
> + *
> + * This driver implements a GPIO (or better GPO as there is no input)
> + * multiplexer based on latches like this:
> + *
> + * CLK0 ----------------------. ,--------.
> + * CLK1 -------------------. `--------|> #0 |
> + * | | |
> + * OUT0 ----------------+--|-----------|D0 Q0|-----|<
> + * OUT1 --------------+-|--|-----------|D1 Q1|-----|<
> + * OUT2 ------------+-|-|--|-----------|D2 Q2|-----|<
> + * OUT3 ----------+-|-|-|--|-----------|D3 Q3|-----|<
> + * OUT4 --------+-|-|-|-|--|-----------|D4 Q4|-----|<
> + * OUT5 ------+-|-|-|-|-|--|-----------|D5 Q5|-----|<
> + * OUT6 ----+-|-|-|-|-|-|--|-----------|D6 Q6|-----|<
> + * OUT7 --+-|-|-|-|-|-|-|--|-----------|D7 Q7|-----|<
> + * | | | | | | | | | `--------'
> + * | | | | | | | | |
> + * | | | | | | | | | ,--------.
> + * | | | | | | | | `-----------|> #1 |
> + * | | | | | | | | | |
> + * | | | | | | | `--------------|D0 Q0|-----|<
> + * | | | | | | `----------------|D1 Q1|-----|<
> + * | | | | | `------------------|D2 Q2|-----|<
> + * | | | | `--------------------|D3 Q3|-----|<
> + * | | | `----------------------|D4 Q4|-----|<
> + * | | `------------------------|D5 Q5|-----|<
> + * | `--------------------------|D6 Q6|-----|<
> + * `----------------------------|D7 Q7|-----|<
> + * `--------'
> + *
> + * The above is just an example. The actual number of number of latches and
> + * the number of inputs per latch is derived from the number of GPIOs given
> + * in the corresponding device tree properties.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio/consumer.h>
> +
> +#include "gpiolib.h"
> +
> +struct gpio_latch_priv {
> + struct gpio_chip gc;
> + struct gpio_descs *clk_gpios;
> + struct gpio_descs *data_gpios;
> + spinlock_t lock;
> + int n_ports;
> + int n_pins;
> + unsigned int *shadow;
> + struct mutex mutex;
> + spinlock_t spinlock;
> +};
> +
> +static int gpio_latch_get_direction(struct gpio_chip *gc, unsigned int offset)
> +{
> + return GPIO_LINE_DIRECTION_OUT;
> +}
> +
> +static void __gpio_latch_set(struct gpio_latch_priv *priv,
I would love to see that renamed to gpio_latch_set_unlocked(). Other
than that, looks good to me.
Bart
> + void (* set)(struct gpio_desc *desc, int value),
> + unsigned int offset, int val)
> +{
> + int latch = offset / priv->n_pins;
> + int i;
> +
> + if (val)
> + priv->shadow[latch] |= BIT(offset % priv->n_pins);
> + else
> + priv->shadow[latch] &= ~BIT(offset % priv->n_pins);
> +
> + for (i = 0; i < priv->n_pins; i++)
> + set(priv->data_gpios->desc[i], priv->shadow[latch] & BIT(i));
> +
> + set(priv->clk_gpios->desc[latch], 1);
> + set(priv->clk_gpios->desc[latch], 0);
> +}
> +
> +static void gpio_latch_set(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + struct gpio_latch_priv *priv = gpiochip_get_data(gc);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&priv->spinlock, flags);
> +
> + __gpio_latch_set(priv, gpiod_set_value, offset, val);
> +
> + spin_unlock_irqrestore(&priv->spinlock, flags);
> +}
> +
> +static void gpio_latch_set_can_sleep(struct gpio_chip *gc, unsigned int offset, int val)
> +{
> + struct gpio_latch_priv *priv = gpiochip_get_data(gc);
> +
> + mutex_lock(&priv->mutex);
> +
> + __gpio_latch_set(priv, gpiod_set_value_cansleep, offset, val);
> +
> + mutex_unlock(&priv->mutex);
> +}
> +
> +static bool gpio_latch_can_sleep(struct gpio_latch_priv *priv)
> +{
> + int i;
> +
> + for (i = 0; i < priv->n_ports; i++)
> + if (gpiod_cansleep(priv->clk_gpios->desc[i]))
> + return true;
> +
> + for (i = 0; i < priv->n_pins; i++)
> + if (gpiod_cansleep(priv->data_gpios->desc[i]))
> + return true;
> +
> + return false;
> +}
> +
> +static int gpio_latch_probe(struct platform_device *pdev)
> +{
> + struct gpio_latch_priv *priv;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->clk_gpios = devm_gpiod_get_array(&pdev->dev, "clk", GPIOD_OUT_LOW);
> + if (IS_ERR(priv->clk_gpios))
> + return PTR_ERR(priv->clk_gpios);
> +
> + priv->data_gpios = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_OUT_LOW);
> + if (IS_ERR(priv->data_gpios))
> + return PTR_ERR(priv->data_gpios);
> +
> + priv->n_ports = priv->clk_gpios->ndescs;
> + priv->n_pins = priv->data_gpios->ndescs;
> +
> + priv->shadow = devm_kcalloc(&pdev->dev, priv->n_ports, sizeof(*priv->shadow),
> + GFP_KERNEL);
> + if (!priv->shadow)
> + return -ENOMEM;
> +
> + if (gpio_latch_can_sleep(priv)) {
> + priv->gc.can_sleep = true;
> + priv->gc.set = gpio_latch_set_can_sleep;
> + mutex_init(&priv->mutex);
> + } else {
> + priv->gc.can_sleep = false;
> + priv->gc.set = gpio_latch_set;
> + spin_lock_init(&priv->spinlock);
> + }
> +
> + priv->gc.get_direction = gpio_latch_get_direction;
> + priv->gc.ngpio = priv->n_ports * priv->n_pins;
> + priv->gc.owner = THIS_MODULE;
> + priv->gc.base = -1;
> + priv->gc.parent = &pdev->dev;
> + priv->gc.of_node = pdev->dev.of_node;
> +
> + platform_set_drvdata(pdev, priv);
> +
> + return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
> +}
> +
> +static const struct of_device_id gpio_latch_ids[] = {
> + {
> + .compatible = "gpio-latch",
> + }, {
> + /* sentinel */
> + }
> +};
> +MODULE_DEVICE_TABLE(of, gpio_latch_ids);
> +
> +static struct platform_driver gpio_latch_driver = {
> + .driver = {
> + .name = "gpio-latch",
> + .of_match_table = gpio_latch_ids,
> + },
> + .probe = gpio_latch_probe,
> +};
> +module_platform_driver(gpio_latch_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
> +MODULE_DESCRIPTION("GPIO latch driver");
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 5:58 ` [PATCH v2 1/2] gpio: Add gpio latch driver Sascha Hauer
2022-08-31 8:01 ` Marco Felsch
2022-08-31 11:50 ` Bartosz Golaszewski
@ 2022-08-31 20:50 ` Andy Shevchenko
2022-09-01 8:20 ` Sascha Hauer
2022-08-31 20:52 ` kernel test robot
2022-09-02 6:42 ` Andy Shevchenko
4 siblings, 1 reply; 12+ messages in thread
From: Andy Shevchenko @ 2022-08-31 20:50 UTC (permalink / raw)
To: Sascha Hauer
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Bartosz Golaszewski,
Sascha Hauer
On Wed, Aug 31, 2022 at 9:02 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
>
> This driver implements a GPIO multiplexer based on latches connected to
> other GPIOs. A set of data GPIOs is connected to the data input of
> multiple latches. The clock input of each latch is driven by another
> set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> are output only.
I'm still unsure it shouldn't be a part of the (not yet in upstream)
driver that I have mentioned before. But let's leave this apart right
now.
...
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
Why?
It seems you misplaced it instead of mod_devicetable.h.
> +#include <linux/gpio/driver.h>
> +#include <linux/platform_device.h>
> +#include <linux/gpio/consumer.h>
Keep above sorted?
...
> + struct mutex mutex;
> + spinlock_t spinlock;
Checkpatch usually complains if locks are not commented. Looking at
the below code, why it's not an (anonymous) union?
...
> + if (val)
> + priv->shadow[latch] |= BIT(offset % priv->n_pins);
> + else
> + priv->shadow[latch] &= ~BIT(offset % priv->n_pins);
I believe shadow should be defined as unsigned long * and hence normal
bit operations can be applied. For example here is assign_bit().
...
> + priv->shadow = devm_kcalloc(&pdev->dev, priv->n_ports, sizeof(*priv->shadow),
> + GFP_KERNEL);
bitmap_zalloc()
> + if (!priv->shadow)
> + return -ENOMEM;
...
> + priv->gc.parent = &pdev->dev;
> + priv->gc.of_node = pdev->dev.of_node;
Redundant as repeating parent above.
...
> +static const struct of_device_id gpio_latch_ids[] = {
> + {
> + .compatible = "gpio-latch",
> + }, {
> + /* sentinel */
> + }
You may compress this to the 2 LoCs.
> +};
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 20:50 ` Andy Shevchenko
@ 2022-09-01 8:20 ` Sascha Hauer
0 siblings, 0 replies; 12+ messages in thread
From: Sascha Hauer @ 2022-09-01 8:20 UTC (permalink / raw)
To: Andy Shevchenko
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Bartosz Golaszewski,
Sascha Hauer
On Wed, Aug 31, 2022 at 11:50:47PM +0300, Andy Shevchenko wrote:
> On Wed, Aug 31, 2022 at 9:02 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> >
> > This driver implements a GPIO multiplexer based on latches connected to
> > other GPIOs. A set of data GPIOs is connected to the data input of
> > multiple latches. The clock input of each latch is driven by another
> > set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> > 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> > are output only.
>
> I'm still unsure it shouldn't be a part of the (not yet in upstream)
> driver that I have mentioned before. But let's leave this apart right
> now.
I don't see how this could be done. The before mentioned driver depends
on a gpio-mux which is a binary decoder. This doesn't have a
correspondence in this driver.
>
> ...
>
> > +#include <linux/err.h>
> > +#include <linux/module.h>
>
> > +#include <linux/of_device.h>
>
> Why?
> It seems you misplaced it instead of mod_devicetable.h.
Ok.
>
> > +#include <linux/gpio/driver.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/gpio/consumer.h>
>
> Keep above sorted?
>
> ...
>
> > + struct mutex mutex;
> > + spinlock_t spinlock;
>
> Checkpatch usually complains if locks are not commented. Looking at
> the below code, why it's not an (anonymous) union?
checkpatch only complains here when given a --subjective. Anyway,
commenting it is a good thing, and a union can be used here.
>
> ...
>
> > + if (val)
> > + priv->shadow[latch] |= BIT(offset % priv->n_pins);
> > + else
> > + priv->shadow[latch] &= ~BIT(offset % priv->n_pins);
>
> I believe shadow should be defined as unsigned long * and hence normal
> bit operations can be applied. For example here is assign_bit().
Good point.
> > +static const struct of_device_id gpio_latch_ids[] = {
> > + {
> > + .compatible = "gpio-latch",
> > + }, {
> > + /* sentinel */
> > + }
>
> You may compress this to the 2 LoCs.
I usually prefer not doing that as it means that we have to reformat it
once we initialize other fields as well, like here for example .data.
Sascha
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 5:58 ` [PATCH v2 1/2] gpio: Add gpio latch driver Sascha Hauer
` (2 preceding siblings ...)
2022-08-31 20:50 ` Andy Shevchenko
@ 2022-08-31 20:52 ` kernel test robot
2022-09-02 6:42 ` Andy Shevchenko
4 siblings, 0 replies; 12+ messages in thread
From: kernel test robot @ 2022-08-31 20:52 UTC (permalink / raw)
To: Sascha Hauer, linux-gpio
Cc: kbuild-all, linux-kernel, Geert Uytterhoeven, Linus Walleij,
Bartosz Golaszewski, kernel, Sascha Hauer
Hi Sascha,
I love your patch! Yet something to improve:
[auto build test ERROR on brgl/gpio/for-next]
[also build test ERROR on linus/master v6.0-rc3 next-20220830]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Sascha-Hauer/gpio-Add-gpio-latch-driver/20220831-135855
base: https://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux.git gpio/for-next
config: s390-randconfig-r021-20220831 (https://download.01.org/0day-ci/archive/20220901/202209010432.NKyeVosI-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/8fab8b8c35fd4faebb003751d6d34fc06093c19e
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Sascha-Hauer/gpio-Add-gpio-latch-driver/20220831-135855
git checkout 8fab8b8c35fd4faebb003751d6d34fc06093c19e
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash drivers/gpio/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
drivers/gpio/gpio-latch.c: In function 'gpio_latch_probe':
>> drivers/gpio/gpio-latch.c:163:18: error: 'struct gpio_chip' has no member named 'of_node'; did you mean 'fwnode'?
163 | priv->gc.of_node = pdev->dev.of_node;
| ^~~~~~~
| fwnode
vim +163 drivers/gpio/gpio-latch.c
123
124 static int gpio_latch_probe(struct platform_device *pdev)
125 {
126 struct gpio_latch_priv *priv;
127
128 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
129 if (!priv)
130 return -ENOMEM;
131
132 priv->clk_gpios = devm_gpiod_get_array(&pdev->dev, "clk", GPIOD_OUT_LOW);
133 if (IS_ERR(priv->clk_gpios))
134 return PTR_ERR(priv->clk_gpios);
135
136 priv->data_gpios = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_OUT_LOW);
137 if (IS_ERR(priv->data_gpios))
138 return PTR_ERR(priv->data_gpios);
139
140 priv->n_ports = priv->clk_gpios->ndescs;
141 priv->n_pins = priv->data_gpios->ndescs;
142
143 priv->shadow = devm_kcalloc(&pdev->dev, priv->n_ports, sizeof(*priv->shadow),
144 GFP_KERNEL);
145 if (!priv->shadow)
146 return -ENOMEM;
147
148 if (gpio_latch_can_sleep(priv)) {
149 priv->gc.can_sleep = true;
150 priv->gc.set = gpio_latch_set_can_sleep;
151 mutex_init(&priv->mutex);
152 } else {
153 priv->gc.can_sleep = false;
154 priv->gc.set = gpio_latch_set;
155 spin_lock_init(&priv->spinlock);
156 }
157
158 priv->gc.get_direction = gpio_latch_get_direction;
159 priv->gc.ngpio = priv->n_ports * priv->n_pins;
160 priv->gc.owner = THIS_MODULE;
161 priv->gc.base = -1;
162 priv->gc.parent = &pdev->dev;
> 163 priv->gc.of_node = pdev->dev.of_node;
164
165 platform_set_drvdata(pdev, priv);
166
167 return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
168 }
169
--
0-DAY CI Kernel Test Service
https://01.org/lkp
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-08-31 5:58 ` [PATCH v2 1/2] gpio: Add gpio latch driver Sascha Hauer
` (3 preceding siblings ...)
2022-08-31 20:52 ` kernel test robot
@ 2022-09-02 6:42 ` Andy Shevchenko
2022-09-02 7:16 ` Sascha Hauer
4 siblings, 1 reply; 12+ messages in thread
From: Andy Shevchenko @ 2022-09-02 6:42 UTC (permalink / raw)
To: Sascha Hauer
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Bartosz Golaszewski,
Sascha Hauer
On Wed, Aug 31, 2022 at 9:02 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
>
> This driver implements a GPIO multiplexer based on latches connected to
> other GPIOs. A set of data GPIOs is connected to the data input of
> multiple latches. The clock input of each latch is driven by another
> set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> are output only.
So, this is for only one type of latches, now I'm wondering why
gpio-74xx-mmio can't cover this case (with probably small
modifications to the code)?
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 12+ messages in thread* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-09-02 6:42 ` Andy Shevchenko
@ 2022-09-02 7:16 ` Sascha Hauer
2022-09-02 7:20 ` Andy Shevchenko
0 siblings, 1 reply; 12+ messages in thread
From: Sascha Hauer @ 2022-09-02 7:16 UTC (permalink / raw)
To: Andy Shevchenko
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Bartosz Golaszewski,
Sascha Hauer
On Fri, Sep 02, 2022 at 09:42:21AM +0300, Andy Shevchenko wrote:
> On Wed, Aug 31, 2022 at 9:02 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> >
> > This driver implements a GPIO multiplexer based on latches connected to
> > other GPIOs. A set of data GPIOs is connected to the data input of
> > multiple latches. The clock input of each latch is driven by another
> > set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> > 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> > are output only.
>
> So, this is for only one type of latches, now I'm wondering why
> gpio-74xx-mmio can't cover this case (with probably small
> modifications to the code)?
gpio-74xx-mmio is about latches connected to a parallel bus. You can
access the GPIOs by doing readl/writel operations. The latches are
driven by the bus logic and likely an additional address decoder.
What I have here instead is a latch fully driven by GPIOs.
Yes, with enough force you could implement it in the gpio-74xx-mmio
driver, but that wouldn't be mmio at all and likely completely different
code pathes.
Sascha
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v2 1/2] gpio: Add gpio latch driver
2022-09-02 7:16 ` Sascha Hauer
@ 2022-09-02 7:20 ` Andy Shevchenko
0 siblings, 0 replies; 12+ messages in thread
From: Andy Shevchenko @ 2022-09-02 7:20 UTC (permalink / raw)
To: Sascha Hauer
Cc: open list:GPIO SUBSYSTEM, Linux Kernel Mailing List,
Geert Uytterhoeven, Linus Walleij, Bartosz Golaszewski,
Sascha Hauer
On Fri, Sep 2, 2022 at 10:16 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Fri, Sep 02, 2022 at 09:42:21AM +0300, Andy Shevchenko wrote:
> > On Wed, Aug 31, 2022 at 9:02 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> > >
> > > This driver implements a GPIO multiplexer based on latches connected to
> > > other GPIOs. A set of data GPIOs is connected to the data input of
> > > multiple latches. The clock input of each latch is driven by another
> > > set of GPIOs. With two 8-bit latches 10 GPIOs can be multiplexed into
> > > 16 GPIOs. GPOs might be a better term as in fact the multiplexed pins
> > > are output only.
> >
> > So, this is for only one type of latches, now I'm wondering why
> > gpio-74xx-mmio can't cover this case (with probably small
> > modifications to the code)?
>
> gpio-74xx-mmio is about latches connected to a parallel bus. You can
> access the GPIOs by doing readl/writel operations. The latches are
> driven by the bus logic and likely an additional address decoder.
>
> What I have here instead is a latch fully driven by GPIOs.
But this reminds me of some kind of gpio-aggregator with a specific
layer on top. To me it really feels that we are (semi-)reinventing a
wheel between the lines...
> Yes, with enough force you could implement it in the gpio-74xx-mmio
> driver, but that wouldn't be mmio at all and likely completely different
> code pathes.
Got it, thanks for elaboration.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 12+ messages in thread