[PATCH 4/8] minnowboard: Add base platform driver for the MinnowBoard

From: Darren Hart <dvhart@linux.intel.com>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	peter.p.waskiewicz.jr@intel.com,
	andriy.shevchenko@linux.intel.com, danders@circuitco.com,
	vishal.l.verma@intel.com, dvhart@linux.intel.com
Cc: Matthew Garrett <matthew.garrett@nebula.com>,
	Grant Likely <grant.likely@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Richard Purdie <richard.purdie@linuxfoundation.org>,
	platform-driver-x86@vger.kernel.org
Subject: [PATCH 4/8] minnowboard: Add base platform driver for the MinnowBoard
Date: Tue, 25 Jun 2013 18:53:24 -0700	[thread overview]
Message-ID: <a459c0b97ea41148af901fc73dbeff98778c7419.1372211451.git.dvhart@linux.intel.com> (raw)
In-Reply-To: <cover.1372211451.git.dvhart@linux.intel.com>
In-Reply-To: <cover.1372211451.git.dvhart@linux.intel.com>

The MinnowBoard (http://www.minnowboard.org) is an Intel Atom (E6xx) plus EG20T
PCH development board. It uses a few GPIO lines for specific purposes and
exposes the rest to the user.

Request the dedicated GPIO lines:
	HWID
	LVDS_DETECT
	PHY_RESET
	LED0
	LED1

Setup platform drivers for the MinnowBoard LEDs using the leds-gpio
driver. Setup led0 and led1 with heartbeat and mmc0 default triggers
respectively.

GPIO lines SUS[0-4] are dual purpose, either for LVDS signaling or as
user GPIO. Determine which via the LVDS_DETECT signal and enable or
disable them accordingly.

Provide a minimal public interface:
	minnow_detect()
	minnow_lvds_detect()
	minnow_hwid()
	minnow_phy_reset()

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Matthew Garrett <matthew.garrett@nebula.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Richard Purdie <richard.purdie@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Waskiewicz <peter.p.waskiewicz.jr@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: platform-driver-x86@vger.kernel.org
---
 drivers/platform/x86/Kconfig            |  20 ++++
 drivers/platform/x86/Makefile           |   1 +
 drivers/platform/x86/minnowboard-gpio.h |  60 ++++++++++
 drivers/platform/x86/minnowboard.c      | 193 ++++++++++++++++++++++++++++++++
 include/linux/minnowboard.h             |  37 ++++++
 5 files changed, 311 insertions(+)
 create mode 100644 drivers/platform/x86/minnowboard-gpio.h
 create mode 100644 drivers/platform/x86/minnowboard.c
 create mode 100644 include/linux/minnowboard.h

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 8577261..154dbf6 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -15,6 +15,26 @@ menuconfig X86_PLATFORM_DEVICES
 
 if X86_PLATFORM_DEVICES
 
+config MINNOWBOARD
+	tristate "MinnowBoard GPIO and LVDS support"
+	depends on LPC_SCH
+	depends on GPIO_SCH
+	depends on GPIO_PCH
+	depends on LEDS_GPIO
+	default n
+	---help---
+	  This driver configures the MinnowBoard fixed functionality GPIO lines.
+
+	  It ensures that the E6XX SUS GPIOs muxed with LVDS signals (SUS[0:2])
+	  are disabled if the LVDS_DETECT signal is asserted.
+
+	  If LED_TRIGGER* are enabled, LED0 will use the heartbeat trigger and
+	  LED1 will use the mmc0 trigger.
+
+	  The Minnow Hardware ID is read from the GPIO HWID lines and logged.
+
+	  If you have a MinnowBoard, say Y or M here.
+
 config ACER_WMI
 	tristate "Acer WMI Laptop Extras"
 	depends on ACPI
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index ef0ec74..45ede1c 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -2,6 +2,7 @@
 # Makefile for linux/drivers/platform/x86
 # x86 Platform-Specific Drivers
 #
+obj-$(CONFIG_MINNOWBOARD)	+= minnowboard.o
 obj-$(CONFIG_ASUS_LAPTOP)	+= asus-laptop.o
 obj-$(CONFIG_ASUS_WMI)		+= asus-wmi.o
 obj-$(CONFIG_ASUS_NB_WMI)	+= asus-nb-wmi.o
diff --git a/drivers/platform/x86/minnowboard-gpio.h b/drivers/platform/x86/minnowboard-gpio.h
new file mode 100644
index 0000000..ccc8361
--- /dev/null
+++ b/drivers/platform/x86/minnowboard-gpio.h
@@ -0,0 +1,60 @@
+/*
+ * MinnowBoard Linux platform driver
+ * Copyright (c) 2013, Intel Corporation.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Author: Darren Hart <dvhart@linux.intel.com>
+ */
+
+/* MinnowBoard GPIO definitions */
+#define GPIO_BTN0 0
+#define GPIO_BTN1 1
+#define GPIO_BTN2 2
+#define GPIO_BTN3 3
+
+#define GPIO_PROG_VOLTAGE 4
+
+/*
+ * If !LVDS_DETECT, the AUX lines are available as GPIO,
+ * otherwise they are used for LVDS signals.
+ */
+#define GPIO_AUX0 5
+#define GPIO_AUX1 6
+#define GPIO_AUX2 7
+#define GPIO_AUX3 8
+#define GPIO_AUX4 9
+
+#define GPIO_LED0 10
+#define GPIO_LED1 11
+
+#define GPIO_USB_VBUS_DETECT 12
+
+#define GPIO_PHY_RESET 13
+
+#define GPIO_PCH0 244
+#define GPIO_PCH1 245
+#define GPIO_PCH2 246
+#define GPIO_PCH3 247
+#define GPIO_PCH4 248
+#define GPIO_PCH5 249
+#define GPIO_PCH6 250
+#define GPIO_PCH7 251
+
+#define GPIO_HWID0 252
+#define GPIO_HWID1 253
+#define GPIO_HWID2 254
+
+#define GPIO_LVDS_DETECT 255
diff --git a/drivers/platform/x86/minnowboard.c b/drivers/platform/x86/minnowboard.c
new file mode 100644
index 0000000..73d59c1
--- /dev/null
+++ b/drivers/platform/x86/minnowboard.c
@@ -0,0 +1,193 @@
+/*
+ * MinnowBoard Linux platform driver
+ * Copyright (c) 2013, Intel Corporation.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Author: Darren Hart <dvhart@linux.intel.com>
+ */
+
+#define pr_fmt(fmt) "MinnowBoard: " fmt
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/dmi.h>
+#include <linux/input.h>
+#include <linux/gpio.h>
+#include <linux/leds.h>
+#include <linux/gpio-sch.h>
+#include <linux/delay.h>
+#include <linux/minnowboard.h>
+#include "minnowboard-gpio.h"
+
+static int minnow_hwid_val = -1;
+
+/* leds-gpio platform device structures */
+static const struct gpio_led minnow_leds[] = {
+	{ .name = "minnow_led0", .gpio = GPIO_LED0, .active_low = 0,
+	  .retain_state_suspended = 1, .default_state = LEDS_GPIO_DEFSTATE_ON,
+	  .default_trigger = "heartbeat"},
+	{ .name = "minnow_led1", .gpio = GPIO_LED1, .active_low = 0,
+	  .retain_state_suspended = 1, .default_state = LEDS_GPIO_DEFSTATE_ON,
+	  .default_trigger = "mmc0"},
+};
+
+static struct gpio_led_platform_data minnow_leds_platform_data = {
+	.num_leds = ARRAY_SIZE(minnow_leds),
+	.leds = (void *) minnow_leds,
+};
+
+static struct platform_device minnow_gpio_leds = {
+	.name =	"leds-gpio",
+	.id = -1,
+	.dev = {
+		.platform_data = &minnow_leds_platform_data,
+	},
+};
+
+static struct gpio hwid_gpios[] = {
+	{ GPIO_HWID0, GPIOF_DIR_IN | GPIOF_EXPORT, "minnow_gpio_hwid0" },
+	{ GPIO_HWID1, GPIOF_DIR_IN | GPIOF_EXPORT, "minnow_gpio_hwid1" },
+	{ GPIO_HWID2, GPIOF_DIR_IN | GPIOF_EXPORT, "minnow_gpio_hwid2" },
+};
+
+int minnow_hwid(void)
+{
+	/* This should never be called prior to minnow_init_module() */
+	WARN_ON_ONCE(minnow_hwid_val == -1);
+	return minnow_hwid_val;
+}
+EXPORT_SYMBOL_GPL(minnow_hwid);
+
+bool minnow_detect(void)
+{
+	const char *cmp;
+
+	cmp = dmi_get_system_info(DMI_BOARD_NAME);
+	if (cmp && strstr(cmp, "MinnowBoard"))
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(minnow_detect);
+
+bool minnow_lvds_detect(void)
+{
+	return !!gpio_get_value(GPIO_LVDS_DETECT);
+}
+EXPORT_SYMBOL_GPL(minnow_lvds_detect);
+
+void minnow_phy_reset(void)
+{
+	/*
+	 * Hold reset for a little over 1ms and allow some time after to ensure
+	 * the PHY has fully woken up.
+	 */
+	gpio_set_value(GPIO_PHY_RESET, 0);
+	usleep_range(1250, 1500);
+	gpio_set_value(GPIO_PHY_RESET, 1);
+	usleep_range(1250, 1500);
+}
+EXPORT_SYMBOL_GPL(minnow_phy_reset);
+
+static int __init minnow_module_init(void)
+{
+	int err, val, i;
+
+	err = -ENODEV;
+	if (!minnow_detect())
+		goto out;
+
+#ifdef MODULE
+/* Load any implicit dependencies that are not built-in */
+#ifdef CONFIG_LPC_SCH_MODULE
+	if (request_module("lpc_sch"))
+		goto out;
+#endif
+#ifdef CONFIG_GPIO_SCH_MODULE
+	if (request_module("gpio-sch"))
+		goto out;
+#endif
+#ifdef CONFIG_GPIO_PCH_MODULE
+	if (request_module("gpio-pch"))
+		goto out;
+#endif
+#endif
+
+	/* HWID GPIOs */
+	err = gpio_request_array(hwid_gpios, ARRAY_SIZE(hwid_gpios));
+	if (err) {
+		pr_err("Failed to request hwid GPIO lines\n");
+		goto out;
+	}
+	minnow_hwid_val = (!!gpio_get_value(GPIO_HWID0)) |
+			  (!!gpio_get_value(GPIO_HWID1) << 1) |
+			  (!!gpio_get_value(GPIO_HWID2) << 2);
+
+	pr_info("Hardware ID: %d\n", minnow_hwid_val);
+
+	err = gpio_request_one(GPIO_LVDS_DETECT, GPIOF_DIR_IN | GPIOF_EXPORT,
+			       "minnow_lvds_detect");
+	if (err) {
+		pr_err("Failed to request LVDS_DETECT GPIO line (%d)\n",
+		       GPIO_LVDS_DETECT);
+		goto out;
+	}
+
+	/* Disable the GPIO lines if LVDS is detected */
+	val = minnow_lvds_detect() ? 1 : 0;
+	pr_info("Aux GPIO lines %s\n", val ? "Disabled" : "Enabled");
+	for (i = 0; i < 5; i++)
+		sch_gpio_resume_set_enable(i, !val);
+
+	/* Reserve the AR8031 PHY's ETH_RESET GPIO line */
+	err = gpio_request_one(GPIO_PHY_RESET,
+			       GPIOF_DIR_OUT | GPIOF_INIT_HIGH | GPIOF_EXPORT,
+			       "minnow_phy_reset");
+	if (err) {
+		pr_err("Failed to request PHY_RESET GPIO line (%d)\n",
+		       GPIO_PHY_RESET);
+		goto out_lvds;
+	}
+
+	/* GPIO LEDs */
+	err = platform_device_register(&minnow_gpio_leds);
+	if (err) {
+		pr_err("Failed to register leds-gpio platform device\n");
+		goto out_phy;
+	}
+	goto out;
+
+ out_phy:
+	gpio_free(GPIO_PHY_RESET);
+
+ out_lvds:
+	gpio_free(GPIO_LVDS_DETECT);
+
+ out:
+	return err;
+}
+
+static void __exit minnow_module_exit(void)
+{
+	gpio_free(GPIO_LVDS_DETECT);
+	gpio_free(GPIO_PHY_RESET);
+	platform_device_unregister(&minnow_gpio_leds);
+}
+
+module_init(minnow_module_init);
+module_exit(minnow_module_exit);
+
+MODULE_LICENSE("GPL");
diff --git a/include/linux/minnowboard.h b/include/linux/minnowboard.h
new file mode 100644
index 0000000..d3608b8
--- /dev/null
+++ b/include/linux/minnowboard.h
@@ -0,0 +1,37 @@
+/*
+ * MinnowBoard Linux platform driver
+ * Copyright (c) 2013, Intel Corporation.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Author: Darren Hart <dvhart@linux.intel.com>
+ */
+
+#ifndef _LINUX_MINNOWBOARD_H
+#define _LINUX_MINNOWBOARD_H
+
+#if defined(CONFIG_MINNOWBOARD) || defined(CONFIG_MINNOWBOARD_MODULE)
+bool minnow_detect(void);
+bool minnow_lvds_detect(void);
+int minnow_hwid(void);
+void minnow_phy_reset(void);
+#else
+#define minnow_detect() (false)
+#define minnow_lvds_detect() (false)
+#define minnow_hwid() (-1)
+#define minnow_phy_reset() do { } while (0)
+#endif /* MINNOWBOARD */
+
+#endif /* _LINUX_MINNOWBOARD_H */
-- 
1.8.1.2

