On Thu 03 Feb 08:47 PST 2022, Vladimir Zapolskiy wrote:
> The change adds handling of optional vbus regulators in the driver.
>
> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-qcom-cci.c | 49 +++++++++++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
> index 775945f7b4cd..2fc7f1f2616f 100644
> --- a/drivers/i2c/busses/i2c-qcom-cci.c
> +++ b/drivers/i2c/busses/i2c-qcom-cci.c
> @@ -11,6 +11,7 @@
> #include <linux/of.h>
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
>
> #define CCI_HW_VERSION 0x0
> #define CCI_RESET_CMD 0x004
> @@ -480,6 +481,20 @@ static void cci_disable_clocks(struct cci *cci)
> static int __maybe_unused cci_suspend_runtime(struct device *dev)
> {
> struct cci *cci = dev_get_drvdata(dev);
> + struct regulator *bus_regulator;
> + unsigned int i;
> +
> + for (i = 0; i < cci->data->num_masters; i++) {
> + if (!cci->master[i].cci)
> + continue;
> +
> + bus_regulator = cci->master[i].adap.bus_regulator;
> + if (!bus_regulator)
> + continue;
> +
> + if (regulator_is_enabled(bus_regulator) > 0)
> + regulator_disable(bus_regulator);
> + }
>
> cci_disable_clocks(cci);
> return 0;
> @@ -488,12 +503,30 @@ static int __maybe_unused cci_suspend_runtime(struct device *dev)
> static int __maybe_unused cci_resume_runtime(struct device *dev)
> {
> struct cci *cci = dev_get_drvdata(dev);
> + struct regulator *bus_regulator;
> + unsigned int i;
> int ret;
>
> ret = cci_enable_clocks(cci);
> if (ret)
> return ret;
>
> + for (i = 0; i < cci->data->num_masters; i++) {
> + if (!cci->master[i].cci)
> + continue;
> +
> + bus_regulator = cci->master[i].adap.bus_regulator;
> + if (!bus_regulator)
> + continue;
> +
> + if (!regulator_is_enabled(bus_regulator)) {
regulator_is_enabled() tests if the regulator is enabled, not if you
have enabled it. So if this is a shared regulator you might learn that
it's already on, skip your regulator_enable() and then the other
consumer turns it off behind your back.
If you want the regulator to be on, you should regulator_enable().
> + ret = regulator_enable(bus_regulator);
> + if (ret)
> + dev_err(dev, "failed to enable regulator: %d\n",
> + ret);
> + }
> + }
> +
> cci_init(cci);
> return 0;
> }
> @@ -593,6 +626,7 @@ static int cci_probe(struct platform_device *pdev)
> dev_dbg(dev, "CCI HW version = 0x%08x", val);
>
> for_each_available_child_of_node(dev->of_node, child) {
> + struct regulator *bus_regulator;
> struct cci_master *master;
> u32 idx;
>
> @@ -637,6 +671,21 @@ static int cci_probe(struct platform_device *pdev)
> master->cci = NULL;
> goto error_i2c;
> }
> +
> + /*
> + * It might be possible to find an optional vbus supply, but
> + * it requires to pass the registration of an I2C adapter
> + * device and its association with a bus device tree node.
> + */
I'm afraid that I don't understand this comment. The regulator is
optional because most of the time we don't control it explicitly.
So a comment like "Control of IO supply is optional" seems more
relevant.
Regards,
Bjorn
> + bus_regulator = devm_regulator_get_optional(&master->adap.dev,
> + "vbus");
> + if (IS_ERR(bus_regulator)) {
> + ret = PTR_ERR(bus_regulator);
> + if (ret == -EPROBE_DEFER)
> + goto error_i2c;
> + bus_regulator = NULL;
> + }
> + master->adap.bus_regulator = bus_regulator;
> }
>
> ret = cci_reset(cci);
> --
> 2.33.0
>
