On 2/27/25 2:22 PM, Chintan Vankar wrote:
MMIO mux driver is designed to parse "mux-reg-masks" and "idle-states"
property independently to configure mux registers. Drawback of this
approach is, while configuring mux-controller one need to specify every
register of memory space with offset and mask in "mux-reg-masks" and
register state to "idle-states", that would be more complex for devices
with large memory space.
Add support to extend the mmio mux driver to configure a specific
register
or set of register in memory space.
Signed-off-by: Chintan Vankar <c-vankar@xxxxxx>
---
drivers/mux/mmio.c | 148 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 122 insertions(+), 26 deletions(-)
diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
index 30a952c34365..8937d0ea2b11 100644
--- a/drivers/mux/mmio.c
+++ b/drivers/mux/mmio.c
@@ -2,7 +2,7 @@
/*
* MMIO register bitfield-controlled multiplexer driver
*
- * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@xxxxxxxxxxxxxx>
+ * Copyright (C) 2017-2025 Pengutronix, Philipp Zabel
<kernel@xxxxxxxxxxxxxx>
*/
#include <linux/bitops.h>
@@ -33,10 +33,84 @@ static const struct of_device_id mux_mmio_dt_ids[]
= {
};
MODULE_DEVICE_TABLE(of, mux_mmio_dt_ids);
+static int reg_mux_get_controllers(const struct device_node *np, char
*prop_name)
+{
+ int ret;
+
+ ret = of_property_count_u32_elems(np, prop_name);
+ if (ret == 0 || ret % 2)
+ ret = -EINVAL;
+
+ return ret;
+}
+
+static int reg_mux_get_controllers_extended(const struct device_node
*np, char *prop_name)
+{
+ int ret;
+
+ ret = of_property_count_u32_elems(np, prop_name);
+ if (ret == 0 || ret % 3)
+ ret = -EINVAL;
+
+ return ret;
+}
+
+static int reg_mux_parse_dt(const struct device_node *np, bool
*mux_reg_masks_state,
+ int *num_fields)
+{
+ int ret;
+
+ if (*mux_reg_masks_state) {
+ ret = reg_mux_get_controllers_extended(np,
"mux-reg-masks-state");
+ if (ret < 0)
+ return ret;
+ *num_fields = ret / 3;
+ } else {
+ ret = reg_mux_get_controllers(np, "mux-reg-masks");
+ if (ret < 0)
+ return ret;
+ *num_fields = ret / 2;
+ }
+ return ret;
+}
+
+static int mux_reg_set_parameters(const struct device_node *np, char
*prop_name, u32 *reg,
+ u32 *mask, int index)
+{
+ int ret;
+
+ ret = of_property_read_u32_index(np, prop_name,
+ 2 * index, reg);
+ if (!ret)
+ ret = of_property_read_u32_index(np, prop_name,
+ 2 * index + 1, mask);
+
+ return ret;
+}
+
+static int mux_reg_set_parameters_extended(const struct device_node
*np, char *prop_name, u32 *reg,
+ u32 *mask, u32 *state, int index)
+{
+ int ret;
+
+ ret = of_property_read_u32_index(np, prop_name,
+ 3 * index, reg);
This is some odd line wrapping, why newline at 55 chars here?
You can go to 80 or 100 if it is readable.
+ if (!ret) {
Just return early, no need for this MISRA-like "single return" junk.
+ ret = of_property_read_u32_index(np, prop_name,
+ 3 * index + 1, mask);
+ if (!ret)
+ ret = of_property_read_u32_index(np, prop_name,
+ 3 * index + 2, state);
+ }
+
+ return ret;
+}
+
static int mux_mmio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
+ bool mux_reg_masks_state = false;
struct regmap_field **fields;
struct mux_chip *mux_chip;
struct regmap *regmap;
@@ -59,15 +133,19 @@ static int mux_mmio_probe(struct platform_device
*pdev)
return dev_err_probe(dev, PTR_ERR(regmap),
"failed to get regmap\n");
- ret = of_property_count_u32_elems(np, "mux-reg-masks");
- if (ret == 0 || ret % 2)
- ret = -EINVAL;
+ if (of_property_present(np, "mux-reg-masks-state"))
+ mux_reg_masks_state = true;
+
+ ret = reg_mux_parse_dt(np, &mux_reg_masks_state, &num_fields);
Why are you passing this bool by pointer? You don't modify it in the
function..
if (ret < 0) {
- dev_err(dev, "mux-reg-masks property missing or invalid: %d\n",
- ret);
+ if (mux_reg_masks_state)
+ dev_err(dev, "mux-reg-masks-state property missing or
invalid: %d\n",
+ ret);
+ else
+ dev_err(dev, "mux-reg-masks property missing or invalid:
%d\n",
+ ret);
return ret;
}
- num_fields = ret / 2;
mux_chip = devm_mux_chip_alloc(dev, num_fields, num_fields *
sizeof(*fields));
@@ -79,19 +157,25 @@ static int mux_mmio_probe(struct platform_device
*pdev)
for (i = 0; i < num_fields; i++) {
struct mux_control *mux = &mux_chip->mux[i];
struct reg_field field;
- s32 idle_state = MUX_IDLE_AS_IS;
+ s32 state, idle_state = MUX_IDLE_AS_IS;
u32 reg, mask;
int bits;
- ret = of_property_read_u32_index(np, "mux-reg-masks",
- 2 * i, ®);
- if (!ret)
- ret = of_property_read_u32_index(np, "mux-reg-masks",
- 2 * i + 1, &mask);
- if (ret < 0) {
- dev_err(dev, "bitfield %d: failed to read mux-reg-masks
property: %d\n",
- i, ret);
- return ret;
+ if (!mux_reg_masks_state) {
+ ret = mux_reg_set_parameters(np, "mux-reg-masks", ®,
&mask, i);
+ if (ret < 0) {
+ dev_err(dev, "bitfield %d: failed to read
mux-reg-masks property: %d\n",
+ i, ret);
+ return ret;
+ }
+ } else {
+ ret = mux_reg_set_parameters_extended(np,
"mux-reg-masks-state", ®,
+ &mask, &state, i);
+ if (ret < 0) {
+ dev_err(dev, "bitfield %d: failed to read
custom-states property: %d\n",
+ i, ret);
+ return ret;
+ }
}
field.reg = reg;
@@ -115,16 +199,28 @@ static int mux_mmio_probe(struct platform_device
*pdev)
bits = 1 + field.msb - field.lsb;
mux->states = 1 << bits;
- of_property_read_u32_index(np, "idle-states", i,
- (u32 *)&idle_state);
- if (idle_state != MUX_IDLE_AS_IS) {
- if (idle_state < 0 || idle_state >= mux->states) {
- dev_err(dev, "bitfield: %d: out of range idle state
%d\n",
- i, idle_state);
- return -EINVAL;
+ if (!mux_reg_masks_state) {
+ of_property_read_u32_index(np, "idle-states", i,
+ (u32 *)&idle_state);
From here down, both branches of this are almost identical, idle_state and
your new "state" var do the same thing, why do you need both?
