[U-Boot] [PATCH v2] i2c: muxes: pca954x: Add support for GPIO reset line

[Moritz Fischer]

This commit adds support for GPIO reset lines matching the
common linux "reset-gpios" devicetree binding.

Signed-off-by: Moritz Fischer <moritz.fisc...@ettus.com>
---

Changes from v1:
- Simon's feedback on ifdef vs IS_ENABLED()

---
 drivers/i2c/muxes/pca954x.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/pca954x.c b/drivers/i2c/muxes/pca954x.c
index 383f72f552..7dee12166d 100644
--- a/drivers/i2c/muxes/pca954x.c
+++ b/drivers/i2c/muxes/pca954x.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2015 - 2016 Xilinx, Inc.
+ * Copyright (C) 2017 National Instruments Corp
  * Written by Michal Simek
  *
  * SPDX-License-Identifier:    GPL-2.0+
@@ -9,7 +10,8 @@
 #include <dm.h>
 #include <errno.h>
 #include <i2c.h>
-#include <asm/gpio.h>
+
+#include <asm-generic/gpio.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -30,6 +32,9 @@ struct chip_desc {
 struct pca954x_priv {
        u32 addr; /* I2C mux address */
        u32 width; /* I2C mux width - number of busses */
+#ifdef CONFIG_DM_GPIO
+       struct gpio_desc gpio_mux_reset;
+#endif /* CONFIG_DM_GPIO */
 };
 
 static const struct chip_desc chips[] = {
@@ -105,10 +110,45 @@ static int pca954x_ofdata_to_platdata(struct udevice *dev)
        return 0;
 }
 
+static int pca954x_probe(struct udevice *dev)
+{
+       if (IS_ENABLED(CONFIG_DM_GPIO)) {
+               struct pca954x_priv *priv = dev_get_priv(dev);
+               int err;
+
+               err = gpio_request_by_name(dev, "reset-gpios", 0,
+                               &priv->gpio_mux_reset, GPIOD_IS_OUT);
+
+               /* it's optional so only bail if we get a real error */
+               if (err && (err != -ENOENT))
+                       return err;
+
+               /* dm will take care of polarity */
+               if (dm_gpio_is_valid(&priv->gpio_mux_reset))
+                       dm_gpio_set_value(&priv->gpio_mux_reset, 0);
+       }
+
+       return 0;
+}
+
+static int pca954x_remove(struct udevice *dev)
+{
+       if (IS_ENABLED(CONFIG_DM_GPIO)) {
+               struct pca954x_priv *priv = dev_get_priv(dev);
+
+               if (dm_gpio_is_valid(&priv->gpio_mux_reset))
+                       dm_gpio_free(dev, &priv->gpio_mux_reset);
+       }
+
+       return 0;
+}
+
 U_BOOT_DRIVER(pca954x) = {
        .name = "pca954x",
        .id = UCLASS_I2C_MUX,
        .of_match = pca954x_ids,
+       .probe = pca954x_probe,
+       .remove = pca954x_remove,
        .ops = &pca954x_ops,
        .ofdata_to_platdata = pca954x_ofdata_to_platdata,
        .priv_auto_alloc_size = sizeof(struct pca954x_priv),
-- 
2.14.1

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