On 18/01/24 00:16, Philipp Zabel wrote:
On Di, 2024-01-16 at 19:58 +0000, Chris Packham wrote:
On 17/01/24 04:18, Philipp Zabel wrote:
On Fr, 2024-01-12 at 17:36 +0100, Krzysztof Kozlowski wrote:
From: Chris Packham chris.packham@alliedtelesis.co.nz
Some hardware designs with multiple PCA954x devices use a reset GPIO connected to all the muxes. Support this configuration by making use of the reset controller framework which can deal with the shared reset GPIOs. Fall back to the old GPIO descriptor method if the reset controller framework is not enabled.
Signed-off-by: Chris Packham chris.packham@alliedtelesis.co.nz Acked-by: Peter Rosin peda@axentia.se Reviewed-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Link: https://scanmail.trustwave.com/?c=20988&d=_ban5W3xRzKSimJ9ijTJ74p10otfq8... Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org
If previous patches are fine, then this commit is independent and could be taken via I2C.
Cc: Chris Packham chris.packham@alliedtelesis.co.nz Cc: Bartosz Golaszewski brgl@bgdev.pl Cc: Sean Anderson sean.anderson@seco.com
drivers/i2c/muxes/i2c-mux-pca954x.c | 46 ++++++++++++++++++++++++----- 1 file changed, 38 insertions(+), 8 deletions(-)
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c index 2219062104fb..1702e8d49b91 100644 --- a/drivers/i2c/muxes/i2c-mux-pca954x.c +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c @@ -49,6 +49,7 @@ #include <linux/pm.h> #include <linux/property.h> #include <linux/regulator/consumer.h> +#include <linux/reset.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <dt-bindings/mux/mux.h> @@ -102,6 +103,9 @@ struct pca954x { unsigned int irq_mask; raw_spinlock_t lock; struct regulator *supply;
struct gpio_desc *reset_gpio;
struct reset_control *reset_cont; };
/* Provide specs for the MAX735x, PCA954x and PCA984x types we know about */
@@ -477,6 +481,35 @@ static int pca954x_init(struct i2c_client *client, struct pca954x *data) return ret; }
+static int pca954x_get_reset(struct device *dev, struct pca954x *data) +{
- data->reset_cont = devm_reset_control_get_optional_shared(dev, NULL);
- 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*/devm_reset_control_get_optional_shared() won't return NULL if the "reset-gpios" property is found in the device tree, so the GPIO fallback is dead code.
Hmm, I was attempting to handle the case where CONFIG_RESET_GPIO wasn't set [...] [...] it looks like we'd get -EPROBE_DEFER. I could change to check for that or just remove the GPIO fallback entirely. Any preference?
I hadn't considered this.
If CONFIG_RESET_GPIO=n, devm_reset_control_get_optional_shared() probably shouldn't return -EPROBE_DEFER. If we change that, the GPIO fallback here can stay as is.
The alternative would be to drop the fallback and select RESET_GPIO. Using -EPROBE_DEFER for fallback detection is no good, as there could be a valid probe deferral if reset-gpio is compiled as a module that will be loaded later.
I did consider adding `select RESET_GPIO` (or maybe just `imply RESET_GPIO`) initially but decided on the fallback as a way of avoiding surprises for existing users. I'll see if anyone else has a different suggestion but assuming nothing else changes I'll work with Krzystof to get an updated patch for this series.