Messages in this thread Patch in this message |  | | From | Andrea Tomassetti <> | | Subject | [PATCH RESEND] mux: gpio-mux: add support for 4:1 2-channels mux | | Date | Thu, 30 Apr 2026 16:11:54 +0200 |
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Some gpio multiplexers, like TMUX1209, offer differential 4:1 or dual 4:1 single-ended channels. Similarly to what already done by the adg792a driver, the gpio-mux driver has to take into account the #mux-control-cells property and allocate as many controllers as advised by it.
So, in the DTS you can now define:
tmux1209: mux-controller { compatible = "gpio-mux"; #mux-control-cells = <1>;
mux-gpios = <&gpio_expander 01 GPIO_ACTIVE_HIGH>, <&gpio_expander 02 GPIO_ACTIVE_HIGH>; };
adcmux30: adcmux30 { compatible = "io-channel-mux"; io-channels = <&adc1 4>; io-channel-names = "parent"; #io-channel-cells = <1>; mux-controls = <&tmux1209 0>;
channels = "S1A", "S2A", "S3A", "S4A"; };
adcmux31: adcmux31 { compatible = "io-channel-mux"; io-channels = <&adc1 5>; io-channel-names = "parent"; #io-channel-cells = <1>; mux-controls = <&tmux1209 1>;
channels = "S1B", "S2B", "S3B", "S4B"; };
Signed-off-by: Andrea Tomassetti <andrea.tomassetti@sipearl.com> --- drivers/mux/gpio.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/drivers/mux/gpio.c b/drivers/mux/gpio.c index 4cc3202c58f3..01ce3f878b9e 100644 --- a/drivers/mux/gpio.c +++ b/drivers/mux/gpio.c @@ -52,12 +52,23 @@ static int mux_gpio_probe(struct platform_device *pdev) int pins; s32 idle_state; int ret; + u32 cells; + int i;
pins = gpiod_count(dev, "mux"); if (pins < 0) return pins;
- mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio)); + ret = device_property_read_u32(dev, "#mux-control-cells", &cells); + if (ret < 0) + cells = 0; + + if (cells >= 2) { + dev_err(dev, "invalid control-cells %u\n", cells); + return -EINVAL; + } + + mux_chip = devm_mux_chip_alloc(dev, cells + 1, sizeof(*mux_gpio)); if (IS_ERR(mux_chip)) return PTR_ERR(mux_chip);
@@ -69,7 +80,9 @@ static int mux_gpio_probe(struct platform_device *pdev) return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios), "failed to get gpios\n"); WARN_ON(pins != mux_gpio->gpios->ndescs); - mux_chip->mux->states = BIT(pins); + + for (i = 0; i < mux_chip->controllers; ++i) + mux_chip->mux[i].states = BIT(pins);
ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state); if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) { base-commit: 80234b5ab240f52fa45d201e899e207b9265ef91 -- 2.51.2
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