mfd: twl4030-gpio driver

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@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

1 files changed, 521 insertions, 0 deletions

diff --git a/drivers/gpio/twl4030-gpio.c b/drivers/gpio/twl4030-gpio.c
new file mode 100644
index 000000000000..37d3eec8730a
--- /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@ti.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");