Message-Id: <200810171915.22830.david-b@pacbell.net>
Date:	Fri, 17 Oct 2008 19:15:22 -0700
From:	David Brownell <david-b@...bell.net>
To:	Samuel Ortiz <sameo@...nedhand.com>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	Tony Lindgren <tony@...mide.com>
Subject: [patch 3/3] twl4030-gpio driver

From: David Brownell <dbrownell@...rs.sourceforge.net>

This adds basic support for the GPIOs in the twl4030 power management
chip.  That includes two open drain LED drivers, and the use of GPIO-0
(and GPIO-1) as MMC/SD card detect switches which can control whether
the VMMC1 (and VMMC2) regulators are active.

This version of the code has a debounce call that will probably be
replaced before long, when a more generic interface exists.

Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@...mide.com>
---
Patch depends on the twl4030-irq patch.

 drivers/gpio/Kconfig        |    7 
 drivers/gpio/Makefile       |    1 
 drivers/gpio/twl4030-gpio.c |  521 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 529 insertions(+)

--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -127,6 +127,13 @@ config GPIO_PCF857X
 	  This driver provides an in-kernel interface to those GPIOs using
 	  platform-neutral GPIO calls.
 
+config GPIO_TWL4030
+	tristate "TWL4030, TWL5030, and TPS659x0 GPIOs"
+	depends on TWL4030_CORE
+	help
+	  Say yes here to access the GPIO signals of various multi-function
+	  power management chips from Texas Instruments.
+
 comment "PCI GPIO expanders:"
 
 config GPIO_BT8XX
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -9,4 +9,5 @@ obj-$(CONFIG_GPIO_MAX732X)	+= max732x.o
 obj-$(CONFIG_GPIO_MCP23S08)	+= mcp23s08.o
 obj-$(CONFIG_GPIO_PCA953X)	+= pca953x.o
 obj-$(CONFIG_GPIO_PCF857X)	+= pcf857x.o
+obj-$(CONFIG_GPIO_TWL4030)	+= twl4030-gpio.o
 obj-$(CONFIG_GPIO_BT8XX)	+= bt8xxgpio.o
--- /dev/null
+++ b/drivers/gpio/twl4030-gpio.c
@@ -0,0 +1,521 @@
+/*
+ * twl4030_gpio.c -- access to GPIOs on TWL4030/TPS659x0 chips
+ *
+ * Copyright (C) 2006-2007 Texas Instruments, Inc.
+ * Copyright (C) 2006 MontaVista Software, Inc.
+ *
+ * Code re-arranged and cleaned up by:
+ *	Syed Mohammed Khasim <x0khasim@...com>
+ *
+ * Initial Code:
+ *	Andy Lowe / Nishanth Menon
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kthread.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/i2c/twl4030.h>
+
+
+/*
+ * The GPIO "subchip" supports 18 GPIOs which can be configured as
+ * inputs or outputs, with pullups or pulldowns on each pin.  Each
+ * GPIO can trigger interrupts on either or both edges.
+ *
+ * GPIO interrupts can be fed to either of two IRQ lines; this is
+ * intended to support multiple hosts.
+ *
+ * There are also two LED pins used sometimes as output-only GPIOs.
+ */
+
+
+static struct gpio_chip twl_gpiochip;
+static int twl4030_gpio_irq_base;
+
+/* genirq interfaces are not available to modules */
+#ifdef MODULE
+#define is_module()	true
+#else
+#define is_module()	false
+#endif
+
+/* GPIO_CTRL Fields */
+#define MASK_GPIO_CTRL_GPIO0CD1		BIT(0)
+#define MASK_GPIO_CTRL_GPIO1CD2		BIT(1)
+#define MASK_GPIO_CTRL_GPIO_ON		BIT(2)
+
+/* Mask for GPIO registers when aggregated into a 32-bit integer */
+#define GPIO_32_MASK			0x0003ffff
+
+/* Data structures */
+static DEFINE_MUTEX(gpio_lock);
+
+/* store usage of each GPIO. - each bit represents one GPIO */
+static unsigned int gpio_usage_count;
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * To configure TWL4030 GPIO module registers
+ */
+static inline int gpio_twl4030_write(u8 address, u8 data)
+{
+	return twl4030_i2c_write_u8(TWL4030_MODULE_GPIO, data, address);
+}
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * LED register offsets (use TWL4030_MODULE_{LED,PWMA,PWMB}))
+ * PWMs A and B are dedicated to LEDs A and B, respectively.
+ */
+
+#define TWL4030_LED_LEDEN	0x0
+
+/* LEDEN bits */
+#define LEDEN_LEDAON		BIT(0)
+#define LEDEN_LEDBON		BIT(1)
+#define LEDEN_LEDAEXT		BIT(2)
+#define LEDEN_LEDBEXT		BIT(3)
+#define LEDEN_LEDAPWM		BIT(4)
+#define LEDEN_LEDBPWM		BIT(5)
+#define LEDEN_PWM_LENGTHA	BIT(6)
+#define LEDEN_PWM_LENGTHB	BIT(7)
+
+#define TWL4030_PWMx_PWMxON	0x0
+#define TWL4030_PWMx_PWMxOFF	0x1
+
+#define PWMxON_LENGTH		BIT(7)
+
+/*----------------------------------------------------------------------*/
+
+/*
+ * To read a TWL4030 GPIO module register
+ */
+static inline int gpio_twl4030_read(u8 address)
+{
+	u8 data;
+	int ret = 0;
+
+	ret = twl4030_i2c_read_u8(TWL4030_MODULE_GPIO, &data, address);
+	return (ret < 0) ? ret : data;
+}
+
+/*----------------------------------------------------------------------*/
+
+static u8 cached_leden;		/* protected by gpio_lock */
+
+/* The LED lines are open drain outputs ... a FET pulls to GND, so an
+ * external pullup is needed.  We could also expose the integrated PWM
+ * as a LED brightness control; we initialize it as "always on".
+ */
+static void twl4030_led_set_value(int led, int value)
+{
+	u8 mask = LEDEN_LEDAON | LEDEN_LEDAPWM;
+	int status;
+
+	if (led)
+		mask <<= 1;
+
+	mutex_lock(&gpio_lock);
+	if (value)
+		cached_leden &= ~mask;
+	else
+		cached_leden |= mask;
+	status = twl4030_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
+			TWL4030_LED_LEDEN);
+	mutex_unlock(&gpio_lock);
+}
+
+static int twl4030_set_gpio_direction(int gpio, int is_input)
+{
+	u8 d_bnk = gpio >> 3;
+	u8 d_msk = BIT(gpio & 0x7);
+	u8 reg = 0;
+	u8 base = REG_GPIODATADIR1 + d_bnk;
+	int ret = 0;
+
+	mutex_lock(&gpio_lock);
+	ret = gpio_twl4030_read(base);
+	if (ret >= 0) {
+		if (is_input)
+			reg = ret & ~d_msk;
+		else
+			reg = ret | d_msk;
+
+		ret = gpio_twl4030_write(base, reg);
+	}
+	mutex_unlock(&gpio_lock);
+	return ret;
+}
+
+static int twl4030_set_gpio_dataout(int gpio, int enable)
+{
+	u8 d_bnk = gpio >> 3;
+	u8 d_msk = BIT(gpio & 0x7);
+	u8 base = 0;
+
+	if (enable)
+		base = REG_SETGPIODATAOUT1 + d_bnk;
+	else
+		base = REG_CLEARGPIODATAOUT1 + d_bnk;
+
+	return gpio_twl4030_write(base, d_msk);
+}
+
+static int twl4030_get_gpio_datain(int gpio)
+{
+	u8 d_bnk = gpio >> 3;
+	u8 d_off = gpio & 0x7;
+	u8 base = 0;
+	int ret = 0;
+
+	if (unlikely((gpio >= TWL4030_GPIO_MAX)
+		|| !(gpio_usage_count & BIT(gpio))))
+		return -EPERM;
+
+	base = REG_GPIODATAIN1 + d_bnk;
+	ret = gpio_twl4030_read(base);
+	if (ret > 0)
+		ret = (ret >> d_off) & 0x1;
+
+	return ret;
+}
+
+/*
+ * Configure debounce timing value for a GPIO pin on TWL4030
+ */
+int twl4030_set_gpio_debounce(int gpio, int enable)
+{
+	u8 d_bnk = gpio >> 3;
+	u8 d_msk = BIT(gpio & 0x7);
+	u8 reg = 0;
+	u8 base = 0;
+	int ret = 0;
+
+	if (unlikely((gpio >= TWL4030_GPIO_MAX)
+		|| !(gpio_usage_count & BIT(gpio))))
+		return -EPERM;
+
+	base = REG_GPIO_DEBEN1 + d_bnk;
+	mutex_lock(&gpio_lock);
+	ret = gpio_twl4030_read(base);
+	if (ret >= 0) {
+		if (enable)
+			reg = ret | d_msk;
+		else
+			reg = ret & ~d_msk;
+
+		ret = gpio_twl4030_write(base, reg);
+	}
+	mutex_unlock(&gpio_lock);
+	return ret;
+}
+EXPORT_SYMBOL(twl4030_set_gpio_debounce);
+
+/*----------------------------------------------------------------------*/
+
+static int twl_request(struct gpio_chip *chip, unsigned offset)
+{
+	int status = 0;
+
+	mutex_lock(&gpio_lock);
+
+	/* Support the two LED outputs as output-only GPIOs. */
+	if (offset >= TWL4030_GPIO_MAX) {
+		u8	ledclr_mask = LEDEN_LEDAON | LEDEN_LEDAEXT
+				| LEDEN_LEDAPWM | LEDEN_PWM_LENGTHA;
+		u8	module = TWL4030_MODULE_PWMA;
+
+		offset -= TWL4030_GPIO_MAX;
+		if (offset) {
+			ledclr_mask <<= 1;
+			module = TWL4030_MODULE_PWMB;
+		}
+
+		/* initialize PWM to always-drive */
+		status = twl4030_i2c_write_u8(module, 0x7f,
+				TWL4030_PWMx_PWMxOFF);
+		if (status < 0)
+			goto done;
+		status = twl4030_i2c_write_u8(module, 0x7f,
+				TWL4030_PWMx_PWMxON);
+		if (status < 0)
+			goto done;
+
+		/* init LED to not-driven (high) */
+		module = TWL4030_MODULE_LED;
+		status = twl4030_i2c_read_u8(module, &cached_leden,
+				TWL4030_LED_LEDEN);
+		if (status < 0)
+			goto done;
+		cached_leden &= ~ledclr_mask;
+		status = twl4030_i2c_write_u8(module, cached_leden,
+				TWL4030_LED_LEDEN);
+		if (status < 0)
+			goto done;
+
+		status = 0;
+		goto done;
+	}
+
+	/* on first use, turn GPIO module "on" */
+	if (!gpio_usage_count) {
+		struct twl4030_gpio_platform_data *pdata;
+		u8 value = MASK_GPIO_CTRL_GPIO_ON;
+
+		/* optionally have the first two GPIOs switch vMMC1
+		 * and vMMC2 power supplies based on card presence.
+		 */
+		pdata = chip->dev->platform_data;
+		value |= pdata->mmc_cd & 0x03;
+
+		status = gpio_twl4030_write(REG_GPIO_CTRL, value);
+	}
+
+	if (!status)
+		gpio_usage_count |= (0x1 << offset);
+
+done:
+	mutex_unlock(&gpio_lock);
+	return status;
+}
+
+static void twl_free(struct gpio_chip *chip, unsigned offset)
+{
+	if (offset >= TWL4030_GPIO_MAX) {
+		twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1);
+		return;
+	}
+
+	mutex_lock(&gpio_lock);
+
+	gpio_usage_count &= ~BIT(offset);
+
+	/* on last use, switch off GPIO module */
+	if (!gpio_usage_count)
+		gpio_twl4030_write(REG_GPIO_CTRL, 0x0);
+
+	mutex_unlock(&gpio_lock);
+}
+
+static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
+{
+	return (offset < TWL4030_GPIO_MAX)
+		? twl4030_set_gpio_direction(offset, 1)
+		: -EINVAL;
+}
+
+static int twl_get(struct gpio_chip *chip, unsigned offset)
+{
+	int status = 0;
+
+	if (offset < TWL4030_GPIO_MAX)
+		status = twl4030_get_gpio_datain(offset);
+	else if (offset == TWL4030_GPIO_MAX)
+		status = cached_leden & LEDEN_LEDAON;
+	else
+		status = cached_leden & LEDEN_LEDBON;
+	return (status < 0) ? 0 : status;
+}
+
+static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
+{
+	if (offset < TWL4030_GPIO_MAX) {
+		twl4030_set_gpio_dataout(offset, value);
+		return twl4030_set_gpio_direction(offset, 0);
+	} else {
+		twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
+		return 0;
+	}
+}
+
+static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	if (offset < TWL4030_GPIO_MAX)
+		twl4030_set_gpio_dataout(offset, value);
+	else
+		twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
+}
+
+static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	return (twl4030_gpio_irq_base && (offset < TWL4030_GPIO_MAX))
+		? (twl4030_gpio_irq_base + offset)
+		: -EINVAL;
+}
+
+static struct gpio_chip twl_gpiochip = {
+	.label			= "twl4030",
+	.owner			= THIS_MODULE,
+	.request		= twl_request,
+	.free			= twl_free,
+	.direction_input	= twl_direction_in,
+	.get			= twl_get,
+	.direction_output	= twl_direction_out,
+	.set			= twl_set,
+	.to_irq			= twl_to_irq,
+	.can_sleep		= 1,
+};
+
+/*----------------------------------------------------------------------*/
+
+static int __devinit gpio_twl4030_pulls(u32 ups, u32 downs)
+{
+	u8		message[6];
+	unsigned	i, gpio_bit;
+
+	/* For most pins, a pulldown was enabled by default.
+	 * We should have data that's specific to this board.
+	 */
+	for (gpio_bit = 1, i = 1; i < 6; i++) {
+		u8		bit_mask;
+		unsigned	j;
+
+		for (bit_mask = 0, j = 0; j < 8; j += 2, gpio_bit <<= 1) {
+			if (ups & gpio_bit)
+				bit_mask |= 1 << (j + 1);
+			else if (downs & gpio_bit)
+				bit_mask |= 1 << (j + 0);
+		}
+		message[i] = bit_mask;
+	}
+
+	return twl4030_i2c_write(TWL4030_MODULE_GPIO, message,
+				REG_GPIOPUPDCTR1, 5);
+}
+
+static int gpio_twl4030_remove(struct platform_device *pdev);
+
+static int __devinit gpio_twl4030_probe(struct platform_device *pdev)
+{
+	struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
+	int ret;
+
+	/* maybe setup IRQs */
+	if (pdata->irq_base) {
+		if (is_module()) {
+			dev_err(&pdev->dev,
+				"can't dispatch IRQs from modules\n");
+			goto no_irqs;
+		}
+		ret = twl4030_sih_setup(TWL4030_MODULE_GPIO);
+		if (ret < 0)
+			return ret;
+		WARN_ON(ret != pdata->irq_base);
+		twl4030_gpio_irq_base = ret;
+	}
+
+no_irqs:
+	/*
+	 * NOTE:  boards may waste power if they don't set pullups
+	 * and pulldowns correctly ... default for non-ULPI pins is
+	 * pulldown, and some other pins may have external pullups
+	 * or pulldowns.  Careful!
+	 */
+	ret = gpio_twl4030_pulls(pdata->pullups, pdata->pulldowns);
+	if (ret)
+		dev_dbg(&pdev->dev, "pullups %.05x %.05x --> %d\n",
+				pdata->pullups, pdata->pulldowns,
+				ret);
+
+	twl_gpiochip.base = pdata->gpio_base;
+	twl_gpiochip.ngpio = TWL4030_GPIO_MAX;
+	twl_gpiochip.dev = &pdev->dev;
+
+	/* NOTE: we assume VIBRA_CTL.VIBRA_EN, in MODULE_AUDIO_VOICE,
+	 * is (still) clear if use_leds is set.
+	 */
+	if (pdata->use_leds)
+		twl_gpiochip.ngpio += 2;
+
+	ret = gpiochip_add(&twl_gpiochip);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+				"could not register gpiochip, %d\n",
+				ret);
+		twl_gpiochip.ngpio = 0;
+		gpio_twl4030_remove(pdev);
+	} else if (pdata->setup) {
+		int status;
+
+		status = pdata->setup(&pdev->dev,
+				pdata->gpio_base, TWL4030_GPIO_MAX);
+		if (status)
+			dev_dbg(&pdev->dev, "setup --> %d\n", status);
+	}
+
+	return ret;
+}
+
+static int __devexit gpio_twl4030_remove(struct platform_device *pdev)
+{
+	struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
+	int status;
+
+	if (pdata->teardown) {
+		status = pdata->teardown(&pdev->dev,
+				pdata->gpio_base, TWL4030_GPIO_MAX);
+		if (status) {
+			dev_dbg(&pdev->dev, "teardown --> %d\n", status);
+			return status;
+		}
+	}
+
+	status = gpiochip_remove(&twl_gpiochip);
+	if (status < 0)
+		return status;
+
+	if (is_module())
+		return 0;
+
+	/* REVISIT no support yet for deregistering all the IRQs */
+	WARN_ON(1);
+	return -EIO;
+}
+
+/* Note:  this hardware lives inside an I2C-based multi-function device. */
+MODULE_ALIAS("platform:twl4030_gpio");
+
+static struct platform_driver gpio_twl4030_driver = {
+	.driver.name	= "twl4030_gpio",
+	.driver.owner	= THIS_MODULE,
+	.probe		= gpio_twl4030_probe,
+	.remove		= __devexit_p(gpio_twl4030_remove),
+};
+
+static int __init gpio_twl4030_init(void)
+{
+	return platform_driver_register(&gpio_twl4030_driver);
+}
+subsys_initcall(gpio_twl4030_init);
+
+static void __exit gpio_twl4030_exit(void)
+{
+	platform_driver_unregister(&gpio_twl4030_driver);
+}
+module_exit(gpio_twl4030_exit);
+
+MODULE_AUTHOR("Texas Instruments, Inc.");
+MODULE_DESCRIPTION("GPIO interface for TWL4030");
+MODULE_LICENSE("GPL");
--
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