i2c: muxes: pca954x: Fix broken reset-gpio usage

Revert commit 690de2902dca ("i2c: muxes: pca954x: Use reset controller
only") and its dependent commit 94c296776403 ("i2c: muxes: pca954x:
Reset if (de)select fails") because the first breaks all users of the
driver, by requiring a completely optional reset-gpio driver.  These
commits cause that mux driver simply stops working when optional
reset-gpio is not included, but that reset-gpio is not pulled anyhow.

Driver cannot remove legacy reset-gpios handling.

Fixes: 690de2902dca ("i2c: muxes: pca954x: Use reset controller only")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index 75c8d08fa24e56fcb22b755133efeab79ea85397..b9f370c9f018c2b065888869e8218399b875f5eb 100644 (file)
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -118,6 +118,7 @@ struct pca954x {
        raw_spinlock_t lock;
        struct regulator *supply;
 
+       struct gpio_desc *reset_gpio;
        struct reset_control *reset_cont;
 };
 
@@ -315,25 +316,6 @@ static u8 pca954x_regval(struct pca954x *data, u8 chan)
                return 1 << chan;
 }
 
-static void pca954x_reset_assert(struct pca954x *data)
-{
-       if (data->reset_cont)
-               reset_control_assert(data->reset_cont);
-}
-
-static void pca954x_reset_deassert(struct pca954x *data)
-{
-       if (data->reset_cont)
-               reset_control_deassert(data->reset_cont);
-}
-
-static void pca954x_reset_mux(struct pca954x *data)
-{
-       pca954x_reset_assert(data);
-       udelay(1);
-       pca954x_reset_deassert(data);
-}
-
 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
        struct pca954x *data = i2c_mux_priv(muxc);
@@ -347,8 +329,6 @@ static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
                ret = pca954x_reg_write(muxc->parent, client, regval);
                data->last_chan = ret < 0 ? 0 : regval;
        }
-       if (ret == -ETIMEDOUT && data->reset_cont)
-               pca954x_reset_mux(data);
 
        return ret;
 }
@@ -358,7 +338,6 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
        struct pca954x *data = i2c_mux_priv(muxc);
        struct i2c_client *client = data->client;
        s32 idle_state;
-       int ret = 0;
 
        idle_state = READ_ONCE(data->idle_state);
        if (idle_state >= 0)
@@ -368,10 +347,8 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
        if (idle_state == MUX_IDLE_DISCONNECT) {
                /* Deselect active channel */
                data->last_chan = 0;
-               ret = pca954x_reg_write(muxc->parent, client,
-                                       data->last_chan);
-               if (ret == -ETIMEDOUT && data->reset_cont)
-                       pca954x_reset_mux(data);
+               return pca954x_reg_write(muxc->parent, client,
+                                        data->last_chan);
        }
 
        /* otherwise leave as-is */
@@ -550,10 +527,29 @@ static int pca954x_get_reset(struct device *dev, struct pca954x *data)
        if (IS_ERR(data->reset_cont))
                return dev_err_probe(dev, PTR_ERR(data->reset_cont),
                                     "Failed to get reset\n");
+       else if (data->reset_cont)
+               return 0;
+
+       /*
+        * fallback to legacy reset-gpios
+        */
+       data->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(data->reset_gpio)) {
+               return dev_err_probe(dev, PTR_ERR(data->reset_gpio),
+                                    "Failed to get reset gpio");
+       }
 
        return 0;
 }
 
+static void pca954x_reset_deassert(struct pca954x *data)
+{
+       if (data->reset_cont)
+               reset_control_deassert(data->reset_cont);
+       else
+               gpiod_set_value_cansleep(data->reset_gpio, 0);
+}
+
 /*
  * I2C init/probing/exit functions
  */
@@ -593,7 +589,7 @@ static int pca954x_probe(struct i2c_client *client)
        if (ret)
                goto fail_cleanup;
 
-       if (data->reset_cont) {
+       if (data->reset_cont || data->reset_gpio) {
                udelay(1);
                pca954x_reset_deassert(data);
                /* Give the chip some time to recover. */