gpio: max732x driver

This adds a driver supporting a family of I2C port expanders from Maxim,
which includes the MAX7319 and MAX7320-7327 chips.

[dbrownell@users.sourceforge.net: minor fixes]
Signed-off-by: Jack Ren <jack.ren@marvell.com>
Signed-off-by: Eric Miao <eric.miao@marvell.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 385 insertions, 0 deletions

diff --git a/drivers/gpio/max732x.c b/drivers/gpio/max732x.c
new file mode 100644
index 000000000000..b51c8135ca28
--- /dev/null
+++ b/drivers/gpio/max732x.c
@@ -0,0 +1,385 @@
+/*
+ *  max732x.c - I2C Port Expander with 8/16 I/O
+ *
+ *  Copyright (C) 2007 Marvell International Ltd.
+ *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
+ *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
+ *
+ *  Derived from drivers/gpio/pca953x.c
+ *
+ *  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; version 2 of the License.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/gpio.h>
+
+#include <linux/i2c.h>
+#include <linux/i2c/max732x.h>
+
+
+/*
+ * Each port of MAX732x (including MAX7319) falls into one of the
+ * following three types:
+ *
+ *   - Push Pull Output
+ *   - Input
+ *   - Open Drain I/O
+ *
+ * designated by 'O', 'I' and 'P' individually according to MAXIM's
+ * datasheets.
+ *
+ * There are two groups of I/O ports, each group usually includes
+ * up to 8 I/O ports, and is accessed by a specific I2C address:
+ *
+ *   - Group A : by I2C address 0b'110xxxx
+ *   - Group B : by I2C address 0b'101xxxx
+ *
+ * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
+ * address used also affects the initial state of output signals.
+ *
+ * Within each group of ports, there are five known combinations of
+ * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
+ * the detailed organization of these ports.
+ *
+ * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
+ * and GPIOs from GROUP_A are numbered before those from GROUP_B
+ * (if there are two groups).
+ *
+ * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
+ * they are not supported by this driver.
+ */
+
+#define PORT_NONE       0x0     /* '/' No Port */
+#define PORT_OUTPUT     0x1     /* 'O' Push-Pull, Output Only */
+#define PORT_INPUT      0x2     /* 'I' Input Only */
+#define PORT_OPENDRAIN  0x3     /* 'P' Open-Drain, I/O */
+
+#define IO_4I4O         0x5AA5  /* O7 O6 I5 I4 I3 I2 O1 O0 */
+#define IO_4P4O         0x5FF5  /* O7 O6 P5 P4 P3 P2 O1 O0 */
+#define IO_8I           0xAAAA  /* I7 I6 I5 I4 I3 I2 I1 I0 */
+#define IO_8P           0xFFFF  /* P7 P6 P5 P4 P3 P2 P1 P0 */
+#define IO_8O           0x5555  /* O7 O6 O5 O4 O3 O2 O1 O0 */
+
+#define GROUP_A(x)      ((x) & 0xffff)  /* I2C Addr: 0b'110xxxx */
+#define GROUP_B(x)      ((x) << 16)     /* I2C Addr: 0b'101xxxx */
+
+static const struct i2c_device_id max732x_id[] = {
+        { "max7319", GROUP_A(IO_8I) },
+        { "max7320", GROUP_B(IO_8O) },
+        { "max7321", GROUP_A(IO_8P) },
+        { "max7322", GROUP_A(IO_4I4O) },
+        { "max7323", GROUP_A(IO_4P4O) },
+        { "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
+        { "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
+        { "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
+        { "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
+        { },
+};
+MODULE_DEVICE_TABLE(i2c, max732x_id);
+
+struct max732x_chip {
+        struct gpio_chip gpio_chip;
+
+        struct i2c_client *client;      /* "main" client */
+        struct i2c_client *client_dummy;
+        struct i2c_client *client_group_a;
+        struct i2c_client *client_group_b;
+
+        unsigned int    mask_group_a;
+        unsigned int    dir_input;
+        unsigned int    dir_output;
+
+        struct mutex    lock;
+        uint8_t         reg_out[2];
+};
+
+static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
+{
+        struct i2c_client *client;
+        int ret;
+
+        client = group_a ? chip->client_group_a : chip->client_group_b;
+        ret = i2c_smbus_write_byte(client, val);
+        if (ret < 0) {
+                dev_err(&client->dev, "failed writing\n");
+                return ret;
+        }
+
+        return 0;
+}
+
+static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
+{
+        struct i2c_client *client;
+        int ret;
+
+        client = group_a ? chip->client_group_a : chip->client_group_b;
+        ret = i2c_smbus_read_byte(client);
+        if (ret < 0) {
+                dev_err(&client->dev, "failed reading\n");
+                return ret;
+        }
+
+        *val = (uint8_t)ret;
+        return 0;
+}
+
+static inline int is_group_a(struct max732x_chip *chip, unsigned off)
+{
+        return (1u << off) & chip->mask_group_a;
+}
+
+static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
+{
+        struct max732x_chip *chip;
+        uint8_t reg_val;
+        int ret;
+
+        chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+        ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
+        if (ret < 0)
+                return 0;
+
+        return reg_val & (1u << (off & 0x7));
+}
+
+static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
+{
+        struct max732x_chip *chip;
+        uint8_t reg_out, mask = 1u << (off & 0x7);
+        int ret;
+
+        chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+        mutex_lock(&chip->lock);
+
+        reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
+        reg_out = (val) ? reg_out | mask : reg_out & ~mask;
+
+        ret = max732x_write(chip, is_group_a(chip, off), reg_out);
+        if (ret < 0)
+                goto out;
+
+        /* update the shadow register then */
+        if (off > 7)
+                chip->reg_out[1] = reg_out;
+        else
+                chip->reg_out[0] = reg_out;
+out:
+        mutex_unlock(&chip->lock);
+}
+
+static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
+{
+        struct max732x_chip *chip;
+        unsigned int mask = 1u << off;
+
+        chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+        if ((mask & chip->dir_input) == 0) {
+                dev_dbg(&chip->client->dev, "%s port %d is output only\n",
+                        chip->client->name, off);
+                return -EACCES;
+        }
+
+        return 0;
+}
+
+static int max732x_gpio_direction_output(struct gpio_chip *gc,
+                unsigned off, int val)
+{
+        struct max732x_chip *chip;
+        unsigned int mask = 1u << off;
+
+        chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+        if ((mask & chip->dir_output) == 0) {
+                dev_dbg(&chip->client->dev, "%s port %d is input only\n",
+                        chip->client->name, off);
+                return -EACCES;
+        }
+
+        max732x_gpio_set_value(gc, off, val);
+        return 0;
+}
+
+static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
+                                        const struct i2c_device_id *id,
+                                        unsigned gpio_start)
+{
+        struct gpio_chip *gc = &chip->gpio_chip;
+        uint32_t id_data = id->driver_data;
+        int i, port = 0;
+
+        for (i = 0; i < 16; i++, id_data >>= 2) {
+                unsigned int mask = 1 << port;
+
+                switch (id_data & 0x3) {
+                case PORT_OUTPUT:
+                        chip->dir_output |= mask;
+                        break;
+                case PORT_INPUT:
+                        chip->dir_input |= mask;
+                        break;
+                case PORT_OPENDRAIN:
+                        chip->dir_output |= mask;
+                        chip->dir_input |= mask;
+                        break;
+                default:
+                        continue;
+                }
+
+                if (i < 8)
+                        chip->mask_group_a |= mask;
+                port++;
+        }
+
+        if (chip->dir_input)
+                gc->direction_input = max732x_gpio_direction_input;
+        if (chip->dir_output) {
+                gc->direction_output = max732x_gpio_direction_output;
+                gc->set = max732x_gpio_set_value;
+        }
+        gc->get = max732x_gpio_get_value;
+        gc->can_sleep = 1;
+
+        gc->base = gpio_start;
+        gc->ngpio = port;
+        gc->label = chip->client->name;
+        gc->owner = THIS_MODULE;
+
+        return port;
+}
+
+static int __devinit max732x_probe(struct i2c_client *client,
+                                   const struct i2c_device_id *id)
+{
+        struct max732x_platform_data *pdata;
+        struct max732x_chip *chip;
+        struct i2c_client *c;
+        uint16_t addr_a, addr_b;
+        int ret, nr_port;
+
+        pdata = client->dev.platform_data;
+        if (pdata == NULL)
+                return -ENODEV;
+
+        chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
+        if (chip == NULL)
+                return -ENOMEM;
+        chip->client = client;
+
+        nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
+
+        addr_a = (client->addr & 0x0f) | 0x60;
+        addr_b = (client->addr & 0x0f) | 0x50;
+
+        switch (client->addr & 0x70) {
+        case 0x60:
+                chip->client_group_a = client;
+                if (nr_port > 7) {
+                        c = i2c_new_dummy(client->adapter, addr_b);
+                        chip->client_group_b = chip->client_dummy = c;
+                }
+                break;
+        case 0x50:
+                chip->client_group_b = client;
+                if (nr_port > 7) {
+                        c = i2c_new_dummy(client->adapter, addr_a);
+                        chip->client_group_a = chip->client_dummy = c;
+                }
+                break;
+        default:
+                dev_err(&client->dev, "invalid I2C address specified %02x\n",
+                                client->addr);
+                ret = -EINVAL;
+                goto out_failed;
+        }
+
+        mutex_init(&chip->lock);
+
+        max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
+        if (nr_port > 7)
+                max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);
+
+        ret = gpiochip_add(&chip->gpio_chip);
+        if (ret)
+                goto out_failed;
+
+        if (pdata->setup) {
+                ret = pdata->setup(client, chip->gpio_chip.base,
+                                chip->gpio_chip.ngpio, pdata->context);
+                if (ret < 0)
+                        dev_warn(&client->dev, "setup failed, %d\n", ret);
+        }
+
+        i2c_set_clientdata(client, chip);
+        return 0;
+
+out_failed:
+        kfree(chip);
+        return ret;
+}
+
+static int __devexit max732x_remove(struct i2c_client *client)
+{
+        struct max732x_platform_data *pdata = client->dev.platform_data;
+        struct max732x_chip *chip = i2c_get_clientdata(client);
+        int ret;
+
+        if (pdata->teardown) {
+                ret = pdata->teardown(client, chip->gpio_chip.base,
+                                chip->gpio_chip.ngpio, pdata->context);
+                if (ret < 0) {
+                        dev_err(&client->dev, "%s failed, %d\n",
+                                        "teardown", ret);
+                        return ret;
+                }
+        }
+
+        ret = gpiochip_remove(&chip->gpio_chip);
+        if (ret) {
+                dev_err(&client->dev, "%s failed, %d\n",
+                                "gpiochip_remove()", ret);
+                return ret;
+        }
+
+        /* unregister any dummy i2c_client */
+        if (chip->client_dummy)
+                i2c_unregister_device(chip->client_dummy);
+
+        kfree(chip);
+        return 0;
+}
+
+static struct i2c_driver max732x_driver = {
+        .driver = {
+                .name   = "max732x",
+                .owner  = THIS_MODULE,
+        },
+        .probe          = max732x_probe,
+        .remove         = __devexit_p(max732x_remove),
+        .id_table       = max732x_id,
+};
+
+static int __init max732x_init(void)
+{
+        return i2c_add_driver(&max732x_driver);
+}
+module_init(max732x_init);
+
+static void __exit max732x_exit(void)
+{
+        i2c_del_driver(&max732x_driver);
+}
+module_exit(max732x_exit);
+
+MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
+MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
+MODULE_LICENSE("GPL");