Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757165Ab0HaKxF (ORCPT ); Tue, 31 Aug 2010 06:53:05 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:61068 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757083Ab0HaKxC (ORCPT ); Tue, 31 Aug 2010 06:53:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:from:to:subject:date:user-agent:cc:references:in-reply-to :organization:mime-version:content-type:content-transfer-encoding :message-id; b=s4pmQLHWdRImf4SDVqCWnbqofpoDdi0I26g6x0NZhbCQ2CDojsQwNyZX5HCYt70PEK J8yuE2uOaKt6oxD4nQ5jTmChdvN4FoxaNdR7mXPakci1VTte6dDAb6bi/5yn08oj8aYJ eV9vAAMo7+r1TsG2UEEunke9iMGEu42VziTwA= From: Florian Fainelli To: David Brownell Subject: [PATCH v3] GPIO: add support for 74x164 serial-in/parallel-out 8-bit shift register Date: Tue, 31 Aug 2010 12:44:07 +0200 User-Agent: KMail/1.13.2 (Linux/2.6.32-24-server; KDE/4.4.2; x86_64; ; ) Cc: Willy Tarreau , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Samuel Ortiz , Miguel Gaio , Juhos Gabor , dbrownell@users.sourceforge.net References: <887649.75421.qm@web180316.mail.gq1.yahoo.com> <201008311017.30445.florian@openwrt.org> In-Reply-To: <201008311017.30445.florian@openwrt.org> Organization: OpenWrt MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201008311244.07567.florian@openwrt.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8479 Lines: 314 From: Miguel Gaio This patch adds support for generic 74x164 serial-in/parallel-out 8-bits shift register. This driver can be used as a GPIO output expander. Signed-off-by: Miguel Gaio Signed-off-by: Juhos Gabor Signed-off-by: Florian Fainelli --- Changes since v1: - renamed nxp_ to gen_ since this driver is generic to all 74HC164 chips - added comment on this driver not handling the 74HC164 daisy-chaining - renamed misused GPIO expanders to Shift registers Changes since v2: - rename 74hc164 to 74x164 diff --git a/drivers/gpio/74x164.c b/drivers/gpio/74x164.c new file mode 100644 index 0000000..9adeed4 --- /dev/null +++ b/drivers/gpio/74x164.c @@ -0,0 +1,228 @@ +/* + * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver + * + * Copyright (C) 2010 Gabor Juhos + * Copyright (C) 2010 Miguel Gaio + * + * 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. + * + * Note: this driver does not support the way 74x164 chips can be + * daisy-chained. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define GEN_74X164_NUM_GPIOS 8 + +struct gen_74x164_chip { + struct device *parent; + struct gpio_chip gpio_chip; + struct mutex lock; + long mask; +}; + +static void gen_74x164_set_value(struct gpio_chip *, unsigned, int); + +static struct gen_74x164_chip *gpio_to_chip(struct gpio_chip *gc) +{ + return container_of(gc, struct gen_74x164_chip, gpio_chip); +} + +static int gen_74x164_direction_input(struct gpio_chip *gc, unsigned offset) +{ + WARN_ON(1); + return -EINVAL; +} + +static int gen_74x164_direction_output(struct gpio_chip *gc, + unsigned offset, int val) +{ + gen_74x164_set_value(gc, offset, val); + return 0; +} + +static int gen_74x164_get_value(struct gpio_chip *gc, unsigned offset) +{ + struct gen_74x164_chip *chip = gpio_to_chip(gc); + int ret; + + mutex_lock(&chip->lock); + ret = test_bit(offset, &chip->mask); + mutex_unlock(&chip->lock); + + return ret; +} + +static void gen_74x164_set_value(struct gpio_chip *gc, + unsigned offset, int val) +{ + struct gen_74x164_chip *chip; + struct gen_74x164_platform_data *pdata; + long mask; + int refresh; + int i; + + chip = gpio_to_chip(gc); + pdata = chip->parent->platform_data; + + mutex_lock(&chip->lock); + if (val) + refresh = (test_and_set_bit(offset, &chip->mask) != val); + else + refresh = (test_and_clear_bit(offset, &chip->mask) != val); + + if (refresh) { + mask = chip->mask; + for (i = 8; i > 0; --i, mask <<= 1) { + gpio_set_value(pdata->gpio_pin_data, mask & 0x80); + gpio_set_value(pdata->gpio_pin_clk, 1); + gpio_set_value(pdata->gpio_pin_clk, 0); + } + } + mutex_unlock(&chip->lock); +} + +static int __devinit gen_74x164_probe(struct platform_device *pdev) +{ + struct gen_74x164_platform_data *pdata; + struct gen_74x164_chip *chip; + struct gpio_chip *gc; + int err; + + pdata = pdev->dev.platform_data; + if (pdata == NULL) { + dev_dbg(&pdev->dev, "no platform data specified\n"); + return -EINVAL; + } + + chip = kzalloc(sizeof(struct gen_74x164_chip), GFP_KERNEL); + if (chip == NULL) { + dev_err(&pdev->dev, "no memory for private data\n"); + return -ENOMEM; + } + + err = gpio_request(pdata->gpio_pin_clk, dev_name(&pdev->dev)); + if (err) { + dev_err(&pdev->dev, "unable to claim gpio %u, err=%d\n", + pdata->gpio_pin_clk, err); + goto err_free_chip; + } + + err = gpio_request(pdata->gpio_pin_data, dev_name(&pdev->dev)); + if (err) { + dev_err(&pdev->dev, "unable to claim gpio %u, err=%d\n", + pdata->gpio_pin_data, err); + goto err_free_clk; + } + + err = gpio_direction_output(pdata->gpio_pin_clk, 0); + if (err) { + dev_err(&pdev->dev, + "unable to set direction of gpio %u, err=%d\n", + pdata->gpio_pin_clk, err); + goto err_free_data; + } + + err = gpio_direction_output(pdata->gpio_pin_data, 0); + if (err) { + dev_err(&pdev->dev, + "unable to set direction of gpio %u, err=%d\n", + pdata->gpio_pin_data, err); + goto err_free_data; + } + + chip->parent = &pdev->dev; + mutex_init(&chip->lock); + + gc = &chip->gpio_chip; + + gc->direction_input = gen_74x164_direction_input; + gc->direction_output = gen_74x164_direction_output; + gc->get = gen_74x164_get_value; + gc->set = gen_74x164_set_value; + gc->can_sleep = 1; + + gc->base = pdata->gpio_base; + gc->ngpio = GEN_74X164_NUM_GPIOS; + gc->label = dev_name(chip->parent); + gc->dev = chip->parent; + gc->owner = THIS_MODULE; + + err = gpiochip_add(&chip->gpio_chip); + if (err) { + dev_err(&pdev->dev, "unable to add gpio chip, err=%d\n", err); + goto err_free_data; + } + + platform_set_drvdata(pdev, chip); + return 0; + +err_free_data: + gpio_free(pdata->gpio_pin_data); +err_free_clk: + gpio_free(pdata->gpio_pin_clk); +err_free_chip: + kfree(chip); + return err; +} + +static int gen_74x164_remove(struct platform_device *pdev) +{ + struct gen_74x164_chip *chip = platform_get_drvdata(pdev); + struct gen_74x164_platform_data *pdata = pdev->dev.platform_data; + + if (chip) { + int err; + + err = gpiochip_remove(&chip->gpio_chip); + if (err) { + dev_err(&pdev->dev, + "unable to remove gpio chip, err=%d\n", + err); + return err; + } + + gpio_free(pdata->gpio_pin_clk); + gpio_free(pdata->gpio_pin_data); + + kfree(chip); + platform_set_drvdata(pdev, NULL); + } + + return 0; +} + +static struct platform_driver gen_74x164_driver = { + .probe = gen_74x164_probe, + .remove = __devexit_p(gen_74x164_remove), + .driver = { + .name = GEN_74X164_DRIVER_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init gen_74x164_init(void) +{ + return platform_driver_register(&gen_74x164_driver); +} +subsys_initcall(gen_74x164_init); + +static void __exit gen_74x164_exit(void) +{ + platform_driver_unregister(&gen_74x164_driver); +} +module_exit(gen_74x164_exit); + +MODULE_AUTHOR("Gabor Juhos "); +MODULE_AUTHOR("Miguel Gaio "); +MODULE_DESCRIPTION("GPIO expander driver for 74X164 8-bits shift register"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" GEN_74X164_DRIVER_NAME); diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 510aa20..fc82c23 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -361,4 +361,13 @@ config GPIO_JANZ_TTL This driver provides support for driving the pins in output mode only. Input mode is not supported. +comment "Shift registers:" + +config GPIO_74X164 + tristate "74x164 serial-in/parallel-out 8-bits shift register" + help + Platform driver for 74x164 compatible serial-in/parallel-out + 8-outputs shift registers. This driver can be used to provide access + to more gpio outputs. + endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index fc6019d..60456a4 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_GPIO_MAX7301) += max7301.o obj-$(CONFIG_GPIO_MAX732X) += max732x.o obj-$(CONFIG_GPIO_MC33880) += mc33880.o obj-$(CONFIG_GPIO_MCP23S08) += mcp23s08.o +obj-$(CONFIG_GPIO_74X164) += 74x164.o obj-$(CONFIG_GPIO_PCA953X) += pca953x.o obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o obj-$(CONFIG_GPIO_PL061) += pl061.o diff --git a/include/linux/74x164.h b/include/linux/74x164.h new file mode 100644 index 0000000..1705732 --- /dev/null +++ b/include/linux/74x164.h @@ -0,0 +1,22 @@ +/* + * 74x164 - Serial-in/parallel-out 8-bits shift register + * + * Copyright (C) 2010 Gabor Juhos + * + * 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. + */ + +#ifndef __74X164_H +#define __74X164_H + +#define GEN_74X164_DRIVER_NAME "74x164" + +struct gen_74x164_platform_data { + unsigned gpio_base; + unsigned gpio_pin_data; + unsigned gpio_pin_clk; +}; + +#endif /* __74x164_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/