From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56CDDECAAA3 for ; Fri, 26 Aug 2022 05:53:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233064AbiHZFxM (ORCPT ); Fri, 26 Aug 2022 01:53:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231315AbiHZFxL (ORCPT ); Fri, 26 Aug 2022 01:53:11 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACB50D074A for ; Thu, 25 Aug 2022 22:53:09 -0700 (PDT) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oRSHD-00020d-Rx; Fri, 26 Aug 2022 07:53:07 +0200 Received: from mfe by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1oRSHD-00071E-0q; Fri, 26 Aug 2022 07:53:07 +0200 Date: Fri, 26 Aug 2022 07:53:07 +0200 From: Marco Felsch To: Sascha Hauer Cc: linux-gpio@vger.kernel.org, Linus Walleij , linux-kernel@vger.kernel.org, kernel@pengutronix.de, Bartosz Golaszewski Subject: Re: [PATCH 1/2] gpio: Add gpio latch driver Message-ID: <20220826055306.tdsmdambl6fjoiop@pengutronix.de> References: <20220825094132.1268174-1-s.hauer@pengutronix.de> <20220825094132.1268174-2-s.hauer@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220825094132.1268174-2-s.hauer@pengutronix.de> User-Agent: NeoMutt/20180716 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: mfe@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-gpio@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org Hi Sascha, nice patche, please see inline. On 22-08-25, 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 > --- > drivers/gpio/Kconfig | 6 ++ > drivers/gpio/Makefile | 1 + > drivers/gpio/gpio-latch.c | 188 ++++++++++++++++++++++++++++++++++++++ > 3 files changed, 195 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..117fcadf76a51 > --- /dev/null > +++ b/drivers/gpio/gpio-latch.c > @@ -0,0 +1,188 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * GPIO latch driver > + * > + * Copyright (C) 2022 Sascha Hauer > + * > + * 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 > +#include > +#include > +#include > +#include > +#include > + > +#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 const struct of_device_id gpio_latch_ids[] = { > + { > + .compatible = "gpio-latch", > + }, { > + /* sentinel */ > + } > +}; > +MODULE_DEVICE_TABLE(of, gpio_latch_ids); Nit normally this is at the end of the file. > +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, 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++) > + gpiod_set_value(priv->data_gpios->desc[i], priv->shadow[latch] & BIT(i)); > + > + gpiod_set_value(priv->clk_gpios->desc[latch], 1); > + gpiod_set_value(priv->clk_gpios->desc[latch], 0); Your have two access function for _can_sleep and "can not sleep" but here you don't resepect it. Regards, Marco > +} > + > +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, 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, 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 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 "); > +MODULE_DESCRIPTION("GPIO latch driver"); > -- > 2.30.2 > > >