mfd: bcm590xx: Add support for secondary I2C slave address

BCM590xx utilizes a secondary I2C slave address to access additional
register space. Add support for the secondary address space by
instantiating a dummy I2C device with the appropriate secondary
I2C slave address. Also expose a secondary regmap register space so
that MFD drivers can access this secondary i2c slave address space.

Signed-off-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

1 files changed, 46 insertions, 14 deletions

diff --git a/drivers/mfd/bcm590xx.c b/drivers/mfd/bcm590xx.c
index e9a33c79431b..43cba1a1973c 100644
--- a/drivers/mfd/bcm590xx.c
+++ b/drivers/mfd/bcm590xx.c
@@ -28,39 +28,71 @@ static const struct mfd_cell bcm590xx_devs[] = {
         },
 };
 
-static const struct regmap_config bcm590xx_regmap_config = {
+static const struct regmap_config bcm590xx_regmap_config_pri = {
         .reg_bits       = 8,
         .val_bits       = 8,
-        .max_register   = BCM590XX_MAX_REGISTER,
+        .max_register   = BCM590XX_MAX_REGISTER_PRI,
         .cache_type     = REGCACHE_RBTREE,
 };
 
-static int bcm590xx_i2c_probe(struct i2c_client *i2c,
+static const struct regmap_config bcm590xx_regmap_config_sec = {
+        .reg_bits       = 8,
+        .val_bits       = 8,
+        .max_register   = BCM590XX_MAX_REGISTER_SEC,
+        .cache_type     = REGCACHE_RBTREE,
+};
+
+static int bcm590xx_i2c_probe(struct i2c_client *i2c_pri,
                               const struct i2c_device_id *id)
 {
         struct bcm590xx *bcm590xx;
         int ret;
 
-        bcm590xx = devm_kzalloc(&i2c->dev, sizeof(*bcm590xx), GFP_KERNEL);
+        bcm590xx = devm_kzalloc(&i2c_pri->dev, sizeof(*bcm590xx), GFP_KERNEL);
         if (!bcm590xx)
                 return -ENOMEM;
 
-        i2c_set_clientdata(i2c, bcm590xx);
-        bcm590xx->dev = &i2c->dev;
-        bcm590xx->i2c_client = i2c;
+        i2c_set_clientdata(i2c_pri, bcm590xx);
+        bcm590xx->dev = &i2c_pri->dev;
+        bcm590xx->i2c_pri = i2c_pri;
 
-        bcm590xx->regmap = devm_regmap_init_i2c(i2c, &bcm590xx_regmap_config);
-        if (IS_ERR(bcm590xx->regmap)) {
-                ret = PTR_ERR(bcm590xx->regmap);
-                dev_err(&i2c->dev, "regmap initialization failed: %d\n", ret);
+        bcm590xx->regmap_pri = devm_regmap_init_i2c(i2c_pri,
+                                                 &bcm590xx_regmap_config_pri);
+        if (IS_ERR(bcm590xx->regmap_pri)) {
+                ret = PTR_ERR(bcm590xx->regmap_pri);
+                dev_err(&i2c_pri->dev, "primary regmap init failed: %d\n", ret);
                 return ret;
         }
 
-        ret = mfd_add_devices(&i2c->dev, -1, bcm590xx_devs,
+        /* Secondary I2C slave address is the base address with A(2) asserted */
+        bcm590xx->i2c_sec = i2c_new_dummy(i2c_pri->adapter,
+                                          i2c_pri->addr | BIT(2));
+        if (IS_ERR_OR_NULL(bcm590xx->i2c_sec)) {
+                dev_err(&i2c_pri->dev, "failed to add secondary I2C device\n");
+                return -ENODEV;
+        }
+        i2c_set_clientdata(bcm590xx->i2c_sec, bcm590xx);
+
+        bcm590xx->regmap_sec = devm_regmap_init_i2c(bcm590xx->i2c_sec,
+                                                &bcm590xx_regmap_config_sec);
+        if (IS_ERR(bcm590xx->regmap_sec)) {
+                ret = PTR_ERR(bcm590xx->regmap_sec);
+                dev_err(&bcm590xx->i2c_sec->dev,
+                        "secondary regmap init failed: %d\n", ret);
+                goto err;
+        }
+
+        ret = mfd_add_devices(&i2c_pri->dev, -1, bcm590xx_devs,
                               ARRAY_SIZE(bcm590xx_devs), NULL, 0, NULL);
-        if (ret < 0)
-                dev_err(&i2c->dev, "failed to add sub-devices: %d\n", ret);
+        if (ret < 0) {
+                dev_err(&i2c_pri->dev, "failed to add sub-devices: %d\n", ret);
+                goto err;
+        }
+
+        return 0;
 
+err:
+        i2c_unregister_device(bcm590xx->i2c_sec);
         return ret;
 }