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Message-Id: <20230615132023.13801-5-andriy.shevchenko@linux.intel.com>
Date: Thu, 15 Jun 2023 16:20:22 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Linus Walleij <linus.walleij@...aro.org>,
Alexander Stein <alexander.stein@...tq-group.com>,
linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org
Cc: Bartosz Golaszewski <brgl@...ev.pl>,
Andy Shevchenko <andy@...nel.org>
Subject: [PATCH v3 4/5] gpio: aggregator: Set up a parser of delay line parameters
The aggregator mode can also handle properties of the platform,
that do not belong to the GPIO controller itself. One of such
a property is a signal delay line. Set up a parser to support it.
Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
drivers/gpio/gpio-aggregator.c | 72 +++++++++++++++++++++++++++++++++-
1 file changed, 70 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c
index 8892cb37ad79..b944ce9e030e 100644
--- a/drivers/gpio/gpio-aggregator.c
+++ b/drivers/gpio/gpio-aggregator.c
@@ -18,6 +18,7 @@
#include <linux/mutex.h>
#include <linux/overflow.h>
#include <linux/platform_device.h>
+#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
@@ -423,6 +424,59 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset)
return gpiod_to_irq(fwd->descs[offset]);
}
+/*
+ * The GPIO delay provides a way to configure platform specific delays
+ * for the GPIO ramp-up or ramp-down delays. This can serve the following
+ * purposes:
+ * - Open-drain output using an RC filter
+ */
+#define FWD_FEATURE_DELAY BIT(0)
+
+#ifdef CONFIG_OF_GPIO
+static int gpiochip_fwd_delay_of_xlate(struct gpio_chip *chip,
+ const struct of_phandle_args *gpiospec,
+ u32 *flags)
+{
+ struct gpiochip_fwd *fwd = gpiochip_get_data(chip);
+ struct gpiochip_fwd_timing *timings;
+ u32 line;
+
+ if (gpiospec->args_count != chip->of_gpio_n_cells)
+ return -EINVAL;
+
+ line = gpiospec->args[0];
+ if (line >= chip->ngpio)
+ return -EINVAL;
+
+ timings = &fwd->delay_timings[line];
+ timings->ramp_up_us = gpiospec->args[1];
+ timings->ramp_down_us = gpiospec->args[2];
+
+ return line;
+}
+
+static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
+ struct gpiochip_fwd *fwd)
+{
+ fwd->delay_timings = devm_kcalloc(dev, chip->ngpio,
+ sizeof(*fwd->delay_timings),
+ GFP_KERNEL);
+ if (!fwd->delay_timings)
+ return -ENOMEM;
+
+ chip->of_xlate = gpiochip_fwd_delay_of_xlate;
+ chip->of_gpio_n_cells = 3;
+
+ return 0;
+}
+#else
+static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *chip,
+ struct gpiochip_fwd *fwd)
+{
+ return 0;
+}
+#endif /* !CONFIG_OF_GPIO */
+
/**
* gpiochip_fwd_create() - Create a new GPIO forwarder
* @dev: Parent device pointer
@@ -430,6 +484,7 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset)
* @descs: Array containing the GPIO descriptors to forward to.
* This array must contain @ngpios entries, and must not be deallocated
* before the forwarder has been destroyed again.
+ * @features: Bitwise ORed features as defined with FWD_FEATURE_*.
*
* This function creates a new gpiochip, which forwards all GPIO operations to
* the passed GPIO descriptors.
@@ -439,7 +494,8 @@ static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset)
*/
static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
unsigned int ngpios,
- struct gpio_desc *descs[])
+ struct gpio_desc *descs[],
+ unsigned long features)
{
const char *label = dev_name(dev);
struct gpiochip_fwd *fwd;
@@ -492,6 +548,12 @@ static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
else
spin_lock_init(&fwd->slock);
+ if (features & FWD_FEATURE_DELAY) {
+ error = gpiochip_fwd_setup_delay_line(dev, chip, fwd);
+ if (error)
+ return ERR_PTR(error);
+ }
+
error = devm_gpiochip_add_data(dev, chip, fwd);
if (error)
return ERR_PTR(error);
@@ -509,6 +571,7 @@ static int gpio_aggregator_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct gpio_desc **descs;
struct gpiochip_fwd *fwd;
+ unsigned long features;
int i, n;
n = gpiod_count(dev, NULL);
@@ -525,7 +588,8 @@ static int gpio_aggregator_probe(struct platform_device *pdev)
return PTR_ERR(descs[i]);
}
- fwd = gpiochip_fwd_create(dev, n, descs);
+ features = (uintptr_t)device_get_match_data(dev);
+ fwd = gpiochip_fwd_create(dev, n, descs, features);
if (IS_ERR(fwd))
return PTR_ERR(fwd);
@@ -534,6 +598,10 @@ static int gpio_aggregator_probe(struct platform_device *pdev)
}
static const struct of_device_id gpio_aggregator_dt_ids[] = {
+ {
+ .compatible = "gpio-delay",
+ .data = (void *)FWD_FEATURE_DELAY,
+ },
/*
* Add GPIO-operated devices controlled from userspace below,
* or use "driver_override" in sysfs.
--
2.40.0.1.gaa8946217a0b
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