onewire: w1-gpio: add ext_pullup_enable pin in platform data

In the process of porting boards to devicetree implemenation, we should
keep information about external circuitry where they belong - the
individual drivers.

This patch adds a way to specify a GPIO to drive the (optional) external
pull-up logic, rather than using a function pointer for that.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Ville Syrjälä <syrjala@sci.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index f01c336233da..6012c4ea3206 100644
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -104,6 +104,13 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
         if (err)
                 goto free_master;
 
+        if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
+                err = gpio_request_one(pdata->ext_pullup_enable_pin,
+                                       GPIOF_INIT_LOW, "w1 pullup");
+                if (err < 0)
+                        goto free_gpio;
+        }
+
         master->data = pdata;
         master->read_bit = w1_gpio_read_bit;
 
@@ -117,15 +124,21 @@ static int __init w1_gpio_probe(struct platform_device *pdev)
 
         err = w1_add_master_device(master);
         if (err)
-                goto free_gpio;
+                goto free_gpio_ext_pu;
 
         if (pdata->enable_external_pullup)
                 pdata->enable_external_pullup(1);
 
+        if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+                gpio_set_value(pdata->ext_pullup_enable_pin, 1);
+
         platform_set_drvdata(pdev, master);
 
         return 0;
 
+ free_gpio_ext_pu:
+        if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+                gpio_free(pdata->ext_pullup_enable_pin);
  free_gpio:
         gpio_free(pdata->pin);
  free_master:
@@ -142,6 +155,9 @@ static int __exit w1_gpio_remove(struct platform_device *pdev)
         if (pdata->enable_external_pullup)
                 pdata->enable_external_pullup(0);
 
+        if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+                gpio_set_value(pdata->ext_pullup_enable_pin, 0);
+
         w1_remove_master_device(master);
         gpio_free(pdata->pin);
         kfree(master);