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Date: Sat, 28 Aug 2010 22:19:16 +0200
From: Florian Fainelli <florian@...nwrt.org>
To: linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
Samuel Ortiz <sameo@...ux.intel.com>,
Miguel Gaio <miguel.gaio@...xo.com>,
Juhos Gabor <juhosg@...nwrt.org>,
David Brownell <dbrownell@...rs.sourceforge.net>
Subject: [PATCH] GPIO: add support for NXP 74HC164 GPIO expander
From: Miguel Gaio <miguel.gaio@...xo.com>
This patch adds support for NXP's 74HC164 GPIO expander.
Signed-off-by: Miguel Gaio <miguel.gaio@...xo.com>
Signed-off-by: Juhos Gabor <jushog@...nwrt.org>
Signed-off-by: Florian Fainelli <florian@...nwrt.org>
---
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 510aa20..1008901 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -361,4 +361,12 @@ config GPIO_JANZ_TTL
This driver provides support for driving the pins in output
mode only. Input mode is not supported.
+comment "Other GPIO expanders"
+
+config GPIO_NXP_74HC164
+ tristate "NXP 74HC164 Output expanders"
+ help
+ Platform driver for NXP 74HC164 8-output Expanders. This
+ provides a GPIO interface supporting outputs.
+
endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fc6019d..63221bf 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-$(CONFIG_GPIO_NXP_74HC164) += nxp_74hc164.o
obj-$(CONFIG_GPIO_PCA953X) += pca953x.o
obj-$(CONFIG_GPIO_PCF857X) += pcf857x.o
obj-$(CONFIG_GPIO_PL061) += pl061.o
diff --git a/drivers/gpio/nxp_74hc164.c b/drivers/gpio/nxp_74hc164.c
new file mode 100644
index 0000000..88cfe8a
--- /dev/null
+++ b/drivers/gpio/nxp_74hc164.c
@@ -0,0 +1,227 @@
+/*
+ * NXP 74HC164 - output expander GPIO driver
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@...nwrt.org>
+ * Copyright (C) 2010 Miguel Gaio <miguel.gaio@...xo.com>
+ *
+ * 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.
+ *
+ * Copy from nxp_74hc153.c code
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+#include <linux/nxp_74hc164.h>
+
+#define NXP_74HC164_NUM_GPIOS 8
+
+struct nxp_74hc164_chip {
+ struct device *parent;
+ struct gpio_chip gpio_chip;
+ struct mutex lock;
+ long mask;
+};
+
+static void nxp_74hc164_set_value(struct gpio_chip *, unsigned, int);
+
+static struct nxp_74hc164_chip *gpio_to_nxp(struct gpio_chip *gc)
+{
+ return container_of(gc, struct nxp_74hc164_chip, gpio_chip);
+}
+
+static int nxp_74hc164_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+ WARN_ON(1);
+ return -EINVAL;
+}
+
+static int nxp_74hc164_direction_output(struct gpio_chip *gc,
+ unsigned offset, int val)
+{
+ nxp_74hc164_set_value(gc, offset, val);
+ return 0;
+}
+
+static int nxp_74hc164_get_value(struct gpio_chip *gc, unsigned offset)
+{
+ struct nxp_74hc164_chip *nxp = gpio_to_nxp(gc);
+ int ret;
+
+ mutex_lock(&nxp->lock);
+ ret = test_bit(offset, &nxp->mask);
+ mutex_unlock(&nxp->lock);
+
+ return ret;
+}
+
+static void nxp_74hc164_set_value(struct gpio_chip *gc,
+ unsigned offset, int val)
+{
+ struct nxp_74hc164_chip *nxp;
+ struct nxp_74hc164_platform_data *pdata;
+ long mask;
+ int refresh;
+ int i;
+
+ nxp = gpio_to_nxp(gc);
+ pdata = nxp->parent->platform_data;
+
+ mutex_lock(&nxp->lock);
+ if (val)
+ refresh = (test_and_set_bit(offset, &nxp->mask) != val);
+ else
+ refresh = (test_and_clear_bit(offset, &nxp->mask) != val);
+
+ if (refresh) {
+ mask = nxp->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(&nxp->lock);
+}
+
+static int __devinit nxp_74hc164_probe(struct platform_device *pdev)
+{
+ struct nxp_74hc164_platform_data *pdata;
+ struct nxp_74hc164_chip *nxp;
+ 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;
+ }
+
+ nxp = kzalloc(sizeof(struct nxp_74hc164_chip), GFP_KERNEL);
+ if (nxp == 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_nxp;
+ }
+
+ 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;
+ }
+
+ nxp->parent = &pdev->dev;
+ mutex_init(&nxp->lock);
+
+ gc = &nxp->gpio_chip;
+
+ gc->direction_input = nxp_74hc164_direction_input;
+ gc->direction_output = nxp_74hc164_direction_output;
+ gc->get = nxp_74hc164_get_value;
+ gc->set = nxp_74hc164_set_value;
+ gc->can_sleep = 1;
+
+ gc->base = pdata->gpio_base;
+ gc->ngpio = NXP_74HC164_NUM_GPIOS;
+ gc->label = dev_name(nxp->parent);
+ gc->dev = nxp->parent;
+ gc->owner = THIS_MODULE;
+
+ err = gpiochip_add(&nxp->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, nxp);
+ return 0;
+
+err_free_data:
+ gpio_free(pdata->gpio_pin_data);
+err_free_clk:
+ gpio_free(pdata->gpio_pin_clk);
+err_free_nxp:
+ kfree(nxp);
+ return err;
+}
+
+static int nxp_74hc164_remove(struct platform_device *pdev)
+{
+ struct nxp_74hc164_chip *nxp = platform_get_drvdata(pdev);
+ struct nxp_74hc164_platform_data *pdata = pdev->dev.platform_data;
+
+ if (nxp) {
+ int err;
+
+ err = gpiochip_remove(&nxp->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(nxp);
+ platform_set_drvdata(pdev, NULL);
+ }
+
+ return 0;
+}
+
+static struct platform_driver nxp_74hc164_driver = {
+ .probe = nxp_74hc164_probe,
+ .remove = __devexit_p(nxp_74hc164_remove),
+ .driver = {
+ .name = NXP_74HC164_DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init nxp_74hc164_init(void)
+{
+ return platform_driver_register(&nxp_74hc164_driver);
+}
+subsys_initcall(nxp_74hc164_init);
+
+static void __exit nxp_74hc164_exit(void)
+{
+ platform_driver_unregister(&nxp_74hc164_driver);
+}
+module_exit(nxp_74hc164_exit);
+
+MODULE_AUTHOR("Gabor Juhos <juhosg@...nwrt.org>");
+MODULE_AUTHOR("Miguel Gaio <miguel.gaio@...xo.com>");
+MODULE_DESCRIPTION("GPIO expander driver for NXP 74HC164");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" NXP_74HC164_DRIVER_NAME);
diff --git a/include/linux/nxp_74hc164.h b/include/linux/nxp_74hc164.h
new file mode 100644
index 0000000..eb0201f
--- /dev/null
+++ b/include/linux/nxp_74hc164.h
@@ -0,0 +1,22 @@
+/*
+ * NXP 74HC164 - Dual 4-input multiplexer defines
+ *
+ * Copyright (C) 2010 Gabor Juhos <juhosg@...nwrt.org>
+ *
+ * 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 _NXP_74HC164_H
+#define _NXP_74HC164_H
+
+#define NXP_74HC164_DRIVER_NAME "nxp-74hc164"
+
+struct nxp_74hc164_platform_data {
+ unsigned gpio_base;
+ unsigned gpio_pin_data;
+ unsigned gpio_pin_clk;
+};
+
+#endif /* _NXP_74HC164_H */
--
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