mux: mmio: Add suspend and resume support

The status of each mux is read during suspend and stored in the private
memory of the mux_chip.
Then the state is restored during the resume.

Reviewed-by: Andrew Davis <afd@ti.com>
Signed-off-by: Thomas Richard (TI.com) <thomas.richard@bootlin.com>
Link: https://patch.msgid.link/20251013-mux-mmio-resume-support-v5-1-de9467ceb2b2@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
index 9993ce38a818de12237cd700e4c19359ea7f4c29..e4ddb1e619237dbb307677a20564eb08f62d11ab 100644 (file)
--- a/drivers/mux/mmio.c
+++ b/drivers/mux/mmio.c
@@ -15,11 +15,25 @@
 #include <linux/property.h>
 #include <linux/regmap.h>
 
+struct mux_mmio {
+       struct regmap_field **fields;
+       unsigned int *hardware_states;
+};
+
+static int mux_mmio_get(struct mux_control *mux, int *state)
+{
+       struct mux_mmio *mux_mmio = mux_chip_priv(mux->chip);
+       unsigned int index = mux_control_get_index(mux);
+
+       return regmap_field_read(mux_mmio->fields[index], state);
+}
+
 static int mux_mmio_set(struct mux_control *mux, int state)
 {
-       struct regmap_field **fields = mux_chip_priv(mux->chip);
+       struct mux_mmio *mux_mmio = mux_chip_priv(mux->chip);
+       unsigned int index = mux_control_get_index(mux);
 
-       return regmap_field_write(fields[mux_control_get_index(mux)], state);
+       return regmap_field_write(mux_mmio->fields[index], state);
 }
 
 static const struct mux_control_ops mux_mmio_ops = {
@@ -43,8 +57,8 @@ static int mux_mmio_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
-       struct regmap_field **fields;
        struct mux_chip *mux_chip;
+       struct mux_mmio *mux_mmio;
        struct regmap *regmap;
        void __iomem *base;
        int num_fields;
@@ -80,12 +94,20 @@ static int mux_mmio_probe(struct platform_device *pdev)
        }
        num_fields = ret / 2;
 
-       mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
-                                      sizeof(*fields));
+       mux_chip = devm_mux_chip_alloc(dev, num_fields, sizeof(struct mux_mmio));
        if (IS_ERR(mux_chip))
                return PTR_ERR(mux_chip);
 
-       fields = mux_chip_priv(mux_chip);
+       mux_mmio = mux_chip_priv(mux_chip);
+
+       mux_mmio->fields = devm_kmalloc(dev, num_fields * sizeof(*mux_mmio->fields), GFP_KERNEL);
+       if (IS_ERR(mux_mmio->fields))
+               return PTR_ERR(mux_mmio->fields);
+
+       mux_mmio->hardware_states = devm_kmalloc(dev, num_fields *
+                                                sizeof(*mux_mmio->hardware_states), GFP_KERNEL);
+       if (IS_ERR(mux_mmio->hardware_states))
+               return PTR_ERR(mux_mmio->hardware_states);
 
        for (i = 0; i < num_fields; i++) {
                struct mux_control *mux = &mux_chip->mux[i];
@@ -115,9 +137,9 @@ static int mux_mmio_probe(struct platform_device *pdev)
                        return -EINVAL;
                }
 
-               fields[i] = devm_regmap_field_alloc(dev, regmap, field);
-               if (IS_ERR(fields[i])) {
-                       ret = PTR_ERR(fields[i]);
+               mux_mmio->fields[i] = devm_regmap_field_alloc(dev, regmap, field);
+               if (IS_ERR(mux_mmio->fields[i])) {
+                       ret = PTR_ERR(mux_mmio->fields[i]);
                        dev_err(dev, "bitfield %d: failed to allocate: %d\n",
                                i, ret);
                        return ret;
@@ -141,13 +163,55 @@ static int mux_mmio_probe(struct platform_device *pdev)
 
        mux_chip->ops = &mux_mmio_ops;
 
+       dev_set_drvdata(dev, mux_chip);
+
        return devm_mux_chip_register(dev, mux_chip);
 }
 
+static int mux_mmio_suspend_noirq(struct device *dev)
+{
+       struct mux_chip *mux_chip = dev_get_drvdata(dev);
+       struct mux_mmio *mux_mmio = mux_chip_priv(mux_chip);
+       unsigned int state;
+       int ret, i;
+
+       for (i = 0; i < mux_chip->controllers; i++) {
+               ret = mux_mmio_get(&mux_chip->mux[i], &state);
+               if (ret) {
+                       dev_err(dev, "control %u: error saving mux: %d\n", i, ret);
+                       return ret;
+               }
+
+               mux_mmio->hardware_states[i] = state;
+       }
+
+       return 0;
+}
+
+static int mux_mmio_resume_noirq(struct device *dev)
+{
+       struct mux_chip *mux_chip = dev_get_drvdata(dev);
+       struct mux_mmio *mux_mmio = mux_chip_priv(mux_chip);
+       int ret, i;
+
+       for (i = 0; i < mux_chip->controllers; i++) {
+               ret = mux_mmio_set(&mux_chip->mux[i], mux_mmio->hardware_states[i]);
+               if (ret) {
+                       dev_err(dev, "control %u: error restoring mux: %d\n", i, ret);
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+
+static DEFINE_NOIRQ_DEV_PM_OPS(mux_mmio_pm_ops, mux_mmio_suspend_noirq, mux_mmio_resume_noirq);
+
 static struct platform_driver mux_mmio_driver = {
        .driver = {
                .name = "mmio-mux",
                .of_match_table = mux_mmio_dt_ids,
+               .pm = pm_sleep_ptr(&mux_mmio_pm_ops),
        },
        .probe = mux_mmio_probe,
 };