gpio: sx150x: add Semtech I2C sx150x gpio expander driver

Add support for Semtech SX150-series I2C GPIO expanders.  Compatible
models include:

8 bits:  sx1508q
16 bits: sx1509q

Signed-off-by: Gregory Bean <gbean@codeaurora.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Trilok Soni <tsoni@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 645 insertions, 0 deletions

diff --git a/drivers/gpio/sx150x.c b/drivers/gpio/sx150x.c
new file mode 100644
index 000000000000..b42f42ca70c3
--- /dev/null
+++ b/drivers/gpio/sx150x.c
@@ -0,0 +1,645 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/i2c/sx150x.h>
+
+struct sx150x_device_data {
+        u8 reg_pullup;
+        u8 reg_pulldn;
+        u8 reg_drain;
+        u8 reg_polarity;
+        u8 reg_dir;
+        u8 reg_data;
+        u8 reg_irq_mask;
+        u8 reg_irq_src;
+        u8 reg_sense;
+        u8 reg_clock;
+        u8 reg_misc;
+        u8 reg_reset;
+        u8 ngpios;
+};
+
+struct sx150x_chip {
+        struct gpio_chip                 gpio_chip;
+        struct i2c_client               *client;
+        const struct sx150x_device_data *dev_cfg;
+        int                              irq_summary;
+        int                              irq_base;
+        u32                              irq_sense;
+        unsigned long                    irq_set_type_pending;
+        struct irq_chip                  irq_chip;
+        struct mutex                     lock;
+};
+
+static const struct sx150x_device_data sx150x_devices[] = {
+        [0] = { /* sx1508q */
+                .reg_pullup   = 0x03,
+                .reg_pulldn   = 0x04,
+                .reg_drain    = 0x05,
+                .reg_polarity = 0x06,
+                .reg_dir      = 0x07,
+                .reg_data     = 0x08,
+                .reg_irq_mask = 0x09,
+                .reg_irq_src  = 0x0c,
+                .reg_sense    = 0x0b,
+                .reg_clock    = 0x0f,
+                .reg_misc     = 0x10,
+                .reg_reset    = 0x7d,
+                .ngpios       = 8
+        },
+        [1] = { /* sx1509q */
+                .reg_pullup   = 0x07,
+                .reg_pulldn   = 0x09,
+                .reg_drain    = 0x0b,
+                .reg_polarity = 0x0d,
+                .reg_dir      = 0x0f,
+                .reg_data     = 0x11,
+                .reg_irq_mask = 0x13,
+                .reg_irq_src  = 0x19,
+                .reg_sense    = 0x17,
+                .reg_clock    = 0x1e,
+                .reg_misc     = 0x1f,
+                .reg_reset    = 0x7d,
+                .ngpios       = 16
+        },
+};
+
+static const struct i2c_device_id sx150x_id[] = {
+        {"sx1508q", 0},
+        {"sx1509q", 1},
+        {}
+};
+MODULE_DEVICE_TABLE(i2c, sx150x_id);
+
+static s32 sx150x_i2c_write(struct i2c_client *client, u8 reg, u8 val)
+{
+        s32 err = i2c_smbus_write_byte_data(client, reg, val);
+
+        if (err < 0)
+                dev_warn(&client->dev,
+                        "i2c write fail: can't write %02x to %02x: %d\n",
+                        val, reg, err);
+        return err;
+}
+
+static s32 sx150x_i2c_read(struct i2c_client *client, u8 reg, u8 *val)
+{
+        s32 err = i2c_smbus_read_byte_data(client, reg);
+
+        if (err >= 0)
+                *val = err;
+        else
+                dev_warn(&client->dev,
+                        "i2c read fail: can't read from %02x: %d\n",
+                        reg, err);
+        return err;
+}
+
+static inline bool offset_is_oscio(struct sx150x_chip *chip, unsigned offset)
+{
+        return (chip->dev_cfg->ngpios == offset);
+}
+
+/*
+ * These utility functions solve the common problem of locating and setting
+ * configuration bits.  Configuration bits are grouped into registers
+ * whose indexes increase downwards.  For example, with eight-bit registers,
+ * sixteen gpios would have their config bits grouped in the following order:
+ * REGISTER N-1 [ f e d c b a 9 8 ]
+ *          N   [ 7 6 5 4 3 2 1 0 ]
+ *
+ * For multi-bit configurations, the pattern gets wider:
+ * REGISTER N-3 [ f f e e d d c c ]
+ *          N-2 [ b b a a 9 9 8 8 ]
+ *          N-1 [ 7 7 6 6 5 5 4 4 ]
+ *          N   [ 3 3 2 2 1 1 0 0 ]
+ *
+ * Given the address of the starting register 'N', the index of the gpio
+ * whose configuration we seek to change, and the width in bits of that
+ * configuration, these functions allow us to locate the correct
+ * register and mask the correct bits.
+ */
+static inline void sx150x_find_cfg(u8 offset, u8 width,
+                                u8 *reg, u8 *mask, u8 *shift)
+{
+        *reg   -= offset * width / 8;
+        *mask   = (1 << width) - 1;
+        *shift  = (offset * width) % 8;
+        *mask <<= *shift;
+}
+
+static s32 sx150x_write_cfg(struct sx150x_chip *chip,
+                        u8 offset, u8 width, u8 reg, u8 val)
+{
+        u8  mask;
+        u8  data;
+        u8  shift;
+        s32 err;
+
+        sx150x_find_cfg(offset, width, &reg, &mask, &shift);
+        err = sx150x_i2c_read(chip->client, reg, &data);
+        if (err < 0)
+                return err;
+
+        data &= ~mask;
+        data |= (val << shift) & mask;
+        return sx150x_i2c_write(chip->client, reg, data);
+}
+
+static int sx150x_get_io(struct sx150x_chip *chip, unsigned offset)
+{
+        u8  reg = chip->dev_cfg->reg_data;
+        u8  mask;
+        u8  data;
+        u8  shift;
+        s32 err;
+
+        sx150x_find_cfg(offset, 1, &reg, &mask, &shift);
+        err = sx150x_i2c_read(chip->client, reg, &data);
+        if (err >= 0)
+                err = (data & mask) != 0 ? 1 : 0;
+
+        return err;
+}
+
+static void sx150x_set_oscio(struct sx150x_chip *chip, int val)
+{
+        sx150x_i2c_write(chip->client,
+                        chip->dev_cfg->reg_clock,
+                        (val ? 0x1f : 0x10));
+}
+
+static void sx150x_set_io(struct sx150x_chip *chip, unsigned offset, int val)
+{
+        sx150x_write_cfg(chip,
+                        offset,
+                        1,
+                        chip->dev_cfg->reg_data,
+                        (val ? 1 : 0));
+}
+
+static int sx150x_io_input(struct sx150x_chip *chip, unsigned offset)
+{
+        return sx150x_write_cfg(chip,
+                                offset,
+                                1,
+                                chip->dev_cfg->reg_dir,
+                                1);
+}
+
+static int sx150x_io_output(struct sx150x_chip *chip, unsigned offset, int val)
+{
+        int err;
+
+        err = sx150x_write_cfg(chip,
+                        offset,
+                        1,
+                        chip->dev_cfg->reg_data,
+                        (val ? 1 : 0));
+        if (err >= 0)
+                err = sx150x_write_cfg(chip,
+                                offset,
+                                1,
+                                chip->dev_cfg->reg_dir,
+                                0);
+        return err;
+}
+
+static int sx150x_gpio_get(struct gpio_chip *gc, unsigned offset)
+{
+        struct sx150x_chip *chip;
+        int status = -EINVAL;
+
+        chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+        if (!offset_is_oscio(chip, offset)) {
+                mutex_lock(&chip->lock);
+                status = sx150x_get_io(chip, offset);
+                mutex_unlock(&chip->lock);
+        }
+
+        return status;
+}
+
+static void sx150x_gpio_set(struct gpio_chip *gc, unsigned offset, int val)
+{
+        struct sx150x_chip *chip;
+
+        chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+        mutex_lock(&chip->lock);
+        if (offset_is_oscio(chip, offset))
+                sx150x_set_oscio(chip, val);
+        else
+                sx150x_set_io(chip, offset, val);
+        mutex_unlock(&chip->lock);
+}
+
+static int sx150x_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+        struct sx150x_chip *chip;
+        int status = -EINVAL;
+
+        chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+        if (!offset_is_oscio(chip, offset)) {
+                mutex_lock(&chip->lock);
+                status = sx150x_io_input(chip, offset);
+                mutex_unlock(&chip->lock);
+        }
+        return status;
+}
+
+static int sx150x_gpio_direction_output(struct gpio_chip *gc,
+                                        unsigned offset,
+                                        int val)
+{
+        struct sx150x_chip *chip;
+        int status = 0;
+
+        chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+        if (!offset_is_oscio(chip, offset)) {
+                mutex_lock(&chip->lock);
+                status = sx150x_io_output(chip, offset, val);
+                mutex_unlock(&chip->lock);
+        }
+        return status;
+}
+
+static int sx150x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
+{
+        struct sx150x_chip *chip;
+
+        chip = container_of(gc, struct sx150x_chip, gpio_chip);
+
+        if (offset >= chip->dev_cfg->ngpios)
+                return -EINVAL;
+
+        if (chip->irq_base < 0)
+                return -EINVAL;
+
+        return chip->irq_base + offset;
+}
+
+static void sx150x_irq_mask(unsigned int irq)
+{
+        struct irq_chip *ic = get_irq_chip(irq);
+        struct sx150x_chip *chip;
+        unsigned n;
+
+        chip = container_of(ic, struct sx150x_chip, irq_chip);
+        n = irq - chip->irq_base;
+
+        sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
+        sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
+}
+
+static void sx150x_irq_unmask(unsigned int irq)
+{
+        struct irq_chip *ic = get_irq_chip(irq);
+        struct sx150x_chip *chip;
+        unsigned n;
+
+        chip = container_of(ic, struct sx150x_chip, irq_chip);
+        n = irq - chip->irq_base;
+
+        sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
+        sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
+                         chip->irq_sense >> (n * 2));
+}
+
+static int sx150x_irq_set_type(unsigned int irq, unsigned int flow_type)
+{
+        struct irq_chip *ic = get_irq_chip(irq);
+        struct sx150x_chip *chip;
+        unsigned n, val = 0;
+
+        if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+                return -EINVAL;
+
+        chip = container_of(ic, struct sx150x_chip, irq_chip);
+        n = irq - chip->irq_base;
+
+        if (flow_type & IRQ_TYPE_EDGE_RISING)
+                val |= 0x1;
+        if (flow_type & IRQ_TYPE_EDGE_FALLING)
+                val |= 0x2;
+
+        chip->irq_sense &= ~(3UL << (n * 2));
+        chip->irq_sense |= val << (n * 2);
+        chip->irq_set_type_pending |= BIT(n);
+        return 0;
+}
+
+static irqreturn_t sx150x_irq_thread_fn(int irq, void *dev_id)
+{
+        struct sx150x_chip *chip = (struct sx150x_chip *)dev_id;
+        unsigned nhandled = 0;
+        unsigned sub_irq;
+        unsigned n;
+        s32 err;
+        u8 val;
+        int i;
+
+        for (i = (chip->dev_cfg->ngpios / 8) - 1; i >= 0; --i) {
+                err = sx150x_i2c_read(chip->client,
+                                      chip->dev_cfg->reg_irq_src - i,
+                                      &val);
+                if (err < 0)
+                        continue;
+
+                sx150x_i2c_write(chip->client,
+                                chip->dev_cfg->reg_irq_src - i,
+                                val);
+                for (n = 0; n < 8; ++n) {
+                        if (val & (1 << n)) {
+                                sub_irq = chip->irq_base + (i * 8) + n;
+                                handle_nested_irq(sub_irq);
+                                ++nhandled;
+                        }
+                }
+        }
+
+        return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
+}
+
+static void sx150x_irq_bus_lock(unsigned int irq)
+{
+        struct irq_chip *ic = get_irq_chip(irq);
+        struct sx150x_chip *chip;
+
+        chip = container_of(ic, struct sx150x_chip, irq_chip);
+
+        mutex_lock(&chip->lock);
+}
+
+static void sx150x_irq_bus_sync_unlock(unsigned int irq)
+{
+        struct irq_chip *ic = get_irq_chip(irq);
+        struct sx150x_chip *chip;
+        unsigned n;
+
+        chip = container_of(ic, struct sx150x_chip, irq_chip);
+
+        while (chip->irq_set_type_pending) {
+                n = __ffs(chip->irq_set_type_pending);
+                chip->irq_set_type_pending &= ~BIT(n);
+                if (!(irq_to_desc(n + chip->irq_base)->status & IRQ_MASKED))
+                        sx150x_write_cfg(chip, n, 2,
+                                        chip->dev_cfg->reg_sense,
+                                        chip->irq_sense >> (n * 2));
+        }
+
+        mutex_unlock(&chip->lock);
+}
+
+static void sx150x_init_chip(struct sx150x_chip *chip,
+                        struct i2c_client *client,
+                        kernel_ulong_t driver_data,
+                        struct sx150x_platform_data *pdata)
+{
+        mutex_init(&chip->lock);
+
+        chip->client                     = client;
+        chip->dev_cfg                    = &sx150x_devices[driver_data];
+        chip->gpio_chip.label            = client->name;
+        chip->gpio_chip.direction_input  = sx150x_gpio_direction_input;
+        chip->gpio_chip.direction_output = sx150x_gpio_direction_output;
+        chip->gpio_chip.get              = sx150x_gpio_get;
+        chip->gpio_chip.set              = sx150x_gpio_set;
+        chip->gpio_chip.to_irq           = sx150x_gpio_to_irq;
+        chip->gpio_chip.base             = pdata->gpio_base;
+        chip->gpio_chip.can_sleep        = 1;
+        chip->gpio_chip.ngpio            = chip->dev_cfg->ngpios;
+        if (pdata->oscio_is_gpo)
+                ++chip->gpio_chip.ngpio;
+
+        chip->irq_chip.name            = client->name;
+        chip->irq_chip.mask            = sx150x_irq_mask;
+        chip->irq_chip.unmask          = sx150x_irq_unmask;
+        chip->irq_chip.set_type        = sx150x_irq_set_type;
+        chip->irq_chip.bus_lock        = sx150x_irq_bus_lock;
+        chip->irq_chip.bus_sync_unlock = sx150x_irq_bus_sync_unlock;
+        chip->irq_summary              = -1;
+        chip->irq_base                 = -1;
+        chip->irq_sense                = 0;
+        chip->irq_set_type_pending     = 0;
+}
+
+static int sx150x_init_io(struct sx150x_chip *chip, u8 base, u16 cfg)
+{
+        int err = 0;
+        unsigned n;
+
+        for (n = 0; err >= 0 && n < (chip->dev_cfg->ngpios / 8); ++n)
+                err = sx150x_i2c_write(chip->client, base - n, cfg >> (n * 8));
+        return err;
+}
+
+static int sx150x_init_hw(struct sx150x_chip *chip,
+                        struct sx150x_platform_data *pdata)
+{
+        int err = 0;
+
+        err = i2c_smbus_write_word_data(chip->client,
+                                        chip->dev_cfg->reg_reset,
+                                        0x3412);
+        if (err < 0)
+                return err;
+
+        err = sx150x_i2c_write(chip->client,
+                        chip->dev_cfg->reg_misc,
+                        0x01);
+        if (err < 0)
+                return err;
+
+        err = sx150x_init_io(chip, chip->dev_cfg->reg_pullup,
+                        pdata->io_pullup_ena);
+        if (err < 0)
+                return err;
+
+        err = sx150x_init_io(chip, chip->dev_cfg->reg_pulldn,
+                        pdata->io_pulldn_ena);
+        if (err < 0)
+                return err;
+
+        err = sx150x_init_io(chip, chip->dev_cfg->reg_drain,
+                        pdata->io_open_drain_ena);
+        if (err < 0)
+                return err;
+
+        err = sx150x_init_io(chip, chip->dev_cfg->reg_polarity,
+                        pdata->io_polarity);
+        if (err < 0)
+                return err;
+
+        if (pdata->oscio_is_gpo)
+                sx150x_set_oscio(chip, 0);
+
+        return err;
+}
+
+static int sx150x_install_irq_chip(struct sx150x_chip *chip,
+                                int irq_summary,
+                                int irq_base)
+{
+        int err;
+        unsigned n;
+        unsigned irq;
+
+        chip->irq_summary = irq_summary;
+        chip->irq_base    = irq_base;
+
+        for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
+                irq = irq_base + n;
+                set_irq_chip_and_handler(irq, &chip->irq_chip, handle_edge_irq);
+                set_irq_nested_thread(irq, 1);
+#ifdef CONFIG_ARM
+                set_irq_flags(irq, IRQF_VALID);
+#else
+                set_irq_noprobe(irq);
+#endif
+        }
+
+        err = request_threaded_irq(irq_summary,
+                                NULL,
+                                sx150x_irq_thread_fn,
+                                IRQF_SHARED | IRQF_TRIGGER_FALLING,
+                                chip->irq_chip.name,
+                                chip);
+        if (err < 0) {
+                chip->irq_summary = -1;
+                chip->irq_base    = -1;
+        }
+
+        return err;
+}
+
+static void sx150x_remove_irq_chip(struct sx150x_chip *chip)
+{
+        unsigned n;
+        unsigned irq;
+
+        free_irq(chip->irq_summary, chip);
+
+        for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
+                irq = chip->irq_base + n;
+                set_irq_handler(irq, NULL);
+                set_irq_chip(irq, NULL);
+        }
+}
+
+static int __devinit sx150x_probe(struct i2c_client *client,
+                                const struct i2c_device_id *id)
+{
+        static const u32 i2c_funcs = I2C_FUNC_SMBUS_BYTE_DATA |
+                                     I2C_FUNC_SMBUS_WRITE_WORD_DATA;
+        struct sx150x_platform_data *pdata;
+        struct sx150x_chip *chip;
+        int rc;
+
+        pdata = client->dev.platform_data;
+        if (!pdata)
+                return -EINVAL;
+
+        if (!i2c_check_functionality(client->adapter, i2c_funcs))
+                return -ENOSYS;
+
+        chip = kzalloc(sizeof(struct sx150x_chip), GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        sx150x_init_chip(chip, client, id->driver_data, pdata);
+        rc = sx150x_init_hw(chip, pdata);
+        if (rc < 0)
+                goto probe_fail_pre_gpiochip_add;
+
+        rc = gpiochip_add(&chip->gpio_chip);
+        if (rc < 0)
+                goto probe_fail_pre_gpiochip_add;
+
+        if (pdata->irq_summary >= 0) {
+                rc = sx150x_install_irq_chip(chip,
+                                        pdata->irq_summary,
+                                        pdata->irq_base);
+                if (rc < 0)
+                        goto probe_fail_post_gpiochip_add;
+        }
+
+        i2c_set_clientdata(client, chip);
+
+        return 0;
+probe_fail_post_gpiochip_add:
+        WARN_ON(gpiochip_remove(&chip->gpio_chip) < 0);
+probe_fail_pre_gpiochip_add:
+        kfree(chip);
+        return rc;
+}
+
+static int __devexit sx150x_remove(struct i2c_client *client)
+{
+        struct sx150x_chip *chip;
+        int rc;
+
+        chip = i2c_get_clientdata(client);
+        rc = gpiochip_remove(&chip->gpio_chip);
+        if (rc < 0)
+                return rc;
+
+        if (chip->irq_summary >= 0)
+                sx150x_remove_irq_chip(chip);
+
+        kfree(chip);
+
+        return 0;
+}
+
+static struct i2c_driver sx150x_driver = {
+        .driver = {
+                .name = "sx150x",
+                .owner = THIS_MODULE
+        },
+        .probe    = sx150x_probe,
+        .remove   = __devexit_p(sx150x_remove),
+        .id_table = sx150x_id,
+};
+
+static int __init sx150x_init(void)
+{
+        return i2c_add_driver(&sx150x_driver);
+}
+subsys_initcall(sx150x_init);
+
+static void __exit sx150x_exit(void)
+{
+        return i2c_del_driver(&sx150x_driver);
+}
+module_exit(sx150x_exit);
+
+MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
+MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("i2c:sx150x");