Re: [PATCH RFC 2/3] ARM: regulator: add Freescale MXS regulator driver

Stefan Wahren
2014-09-09T18:55:28Z

Hi,

Am 09.09.2014 20:22, schrieb Mark Rutland:
> [...]
>
>> + regs = (__raw_readl(sreg->base_addr) & ~BM_POWER_LEVEL_TRG);
>
> I suspect you should be using the *_relaxed accessors rather than the
> __raw_* accessors.
>
> [...]
>
>> +static int mxs_regulator_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct device_node *np = dev->of_node;
>> + struct device_node *parent;
>> + struct regulator_desc *rdesc;
>> + struct regulator_dev *rdev;
>> + struct mxs_regulator *sreg;
>> + struct regulator_init_data *initdata;
>> + struct regulation_constraints *con;
>> + struct regulator_config config = { };
>> + void __iomem *base_addr = NULL;
>> + void __iomem *power_addr = NULL;
>> + u64 regaddr64 = 0;
>> + const u32 *regaddr_p;
>> + u32 val = 0;
>> + int ret;
>> +
>> + if (!np) {
>> + dev_err(dev, "missing device tree\n");
>> + return -EINVAL;
>> + }
>> +
>> + /* get device base address */
>> + base_addr = of_iomap(np, 0);
>> + if (!base_addr)
>> + return -ENXIO;
>> +
>> + parent = of_get_parent(np);
>> + if (!parent)
>> + return -ENXIO;
>
> Leak of the (successfully mapped) base_addr.
>
>> +
>> + power_addr = of_iomap(parent, 0);
>> + if (!power_addr)
>> + return -ENXIO;
>
> Leak of base_addr and dangling refcount on parent. These apply to all
> subsequent returns.
>
>> +
>> + regaddr_p = of_get_address(np, 0, NULL, NULL);
>
> of_get_address returns a __be32*, not a u32*, so sparse will be very
> unhappy here...
>
>> + if (regaddr_p)
>> + regaddr64 = of_translate_address(np, regaddr_p);
>
> ...and as of_translate_address returns a u64 you'll need a separate
> variable for the input and output.
>
>> +
>> + if (!regaddr64) {
>> + dev_err(dev, "no or invalid reg property set\n");
>> + return -EINVAL;
>> + }
>> +
>> + initdata = of_get_regulator_init_data(dev, np);
>> + if (!initdata)
>> + return -EINVAL;
>> +
>> + ret = of_property_read_u32(np, "mxs-max-reg-val",
>> + &val);
>> + if (!val) {
>> + dev_err(dev, "no or invalid mxs-max-reg-val property set\n");
>> + return ret;
>> + }
>> +
>> + dev_info(dev, "regulator found\n");
>> +
>> + sreg = devm_kzalloc(dev, sizeof(*sreg), GFP_KERNEL);
>> + if (!sreg)
>> + return -ENOMEM;
>> + sreg->initdata = initdata;
>> + sreg->name = of_get_property(np, "regulator-name", NULL);
>
> I'm not keen on using of_get_property here. We have no idea if
> regulator-name is even a string (it should be, but we have no
> guarantee).

Better using of_property_read_string?

>
>> + sreg->cur_uA = 0;
>> + sreg->cur_uV = 0;
>> + sreg->base_addr = base_addr;
>> + sreg->power_addr = power_addr;
>> + init_waitqueue_head(&sreg->wait_q);
>> + spin_lock_init(&sreg->lock);
>> + sreg->max_reg_val = val;
>> +
>> + rdesc = &sreg->rdesc;
>> + rdesc->name = sreg->name;
>> + rdesc->owner = THIS_MODULE;
>> + rdesc->ops = &mxs_rops;
>> +
>> + if (strcmp(rdesc->name, "overall_current") == 0)
>> + rdesc->type = REGULATOR_CURRENT;
>> + else
>> + rdesc->type = REGULATOR_VOLTAGE;
>
> Wouldn't it make more sense to explicitly match the names you expect?
>

Okay, i make "regulator-name" a required property and use a white list
of all possible regulators.

>> + con = &initdata->constraints;
>> + rdesc->n_voltages = sreg->max_reg_val;
>> + rdesc->min_uV = con->min_uV;
>> + rdesc->uV_step = (con->max_uV - con->min_uV) / sreg->max_reg_val;
>> + rdesc->linear_min_sel = 0;
>> + rdesc->vsel_reg = regaddr64;
>> + rdesc->vsel_mask = BM_POWER_LEVEL_TRG;
>> +
>> + config.dev = &pdev->dev;
>> + config.init_data = initdata;
>> + config.driver_data = sreg;
>> + config.of_node = np;
>> +
>> + pr_debug("probing regulator %s %s %d\n",
>> + sreg->name,
>> + rdesc->name,
>> + pdev->id);
>
> Aren't those two names always the same per the code above?
>

Sure, i will fix that.

>> +
>> + /* register regulator */
>> + rdev = devm_regulator_register(dev, rdesc, &config);
>> +
>> + if (IS_ERR(rdev)) {
>> + dev_err(&pdev->dev, "failed to register %s\n",
>> + rdesc->name);
>> + return PTR_ERR(rdev);
>> + }
>> +
>> + if (sreg->max_uA) {
>> + struct regulator *regu;
>> +
>> + regu = regulator_get(NULL, sreg->name);
>> + sreg->nb.notifier_call = reg_callback;
>> + regulator_register_notifier(regu, &sreg->nb);
>> + }
>> +
>> + platform_set_drvdata(pdev, rdev);
>> +
>> + of_property_read_u32(np, "mxs-default-microvolt",
>> + &val);
>> +
>> + if (val)
>> + mxs_set_voltage(rdev, val, val, NULL);
>
> As I mentioned in my comments on the binding, I'd like to know why this
> is necessary and if it is why it shouldn't be a standardised property.

From my understanding the standardised properties only defines a range,
but no default state of the regulators. If the initialization from the
bootloader or a hardcoded initialization in the driver is okay then the
property is not necessary.

> Mark.
>

Thanks for your feedback.

Stefan