Re: [PATCH v4] clock: max77686: Add driver for Maxim 77686 32KHz crystal oscillator

[jonghwa3.lee@samsung.com]

Hi Mike,

On 2012년 08월 24일 11:07, Mike Turquette wrote:
> Hello Jonghwa,
>
> Quoting Jonghwa Lee (2012-06-27 03:31:17)
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/err.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/mfd/max77686.h>
>> +#include <linux/mfd/max77686-private.h>
>> +#include <linux/clk-private.h>
> Please use clk-provider.h.  I don't see any reason for this code to need
> clk-private.h.
Yes, you're right. I missed to change it. I'll update it.
>> +#include <linux/mutex.h>
>> +#include <linux/clkdev.h>
>> +
>> +#define        MAX77686_CLKS_NUM 3
>> +
>> +struct clk_max77686 {
>> +       struct max77686_dev *iodev;
>> +       u32 mask;
>> +       struct clk_hw hw;
>> +       struct clk_lookup *lookup;
>> +};
>> +
>> +static struct clk_max77686 *get_max77686_clk(struct clk_hw *hw)
>> +{
>> +       return container_of(hw, struct clk_max77686, hw);
>> +}
>> +
>> +static int max77686_clk_enable(struct clk_hw *hw)
> Please rename this function to max77686_clk_prepare to reflect that is
> is the .prepare callback.
Okay.
>> +{
>> +       struct clk_max77686 *max77686;
>> +       int ret;
>> +
>> +       max77686 = get_max77686_clk(hw);
>> +       if (!max77686)
>> +               return -ENOMEM;
>> +
>> +       ret = regmap_update_bits(max77686->iodev->regmap,
>> +               MAX77686_REG_32KHZ, max77686->mask, max77686->mask);
>> +
>> +       return ret;
>> +}
>> +
>> +static void max77686_clk_disable(struct clk_hw *hw)
> Please rename this function to max77686_clk_unprepare to reflect that is
> is the .unprepare callback.

Okay.

>> +{
>> +       struct clk_max77686 *max77686;
>> +
>> +       max77686 = get_max77686_clk(hw);
>> +       if (!max77686)
>> +               return;
>> +
>> +       regmap_update_bits(max77686->iodev->regmap,
>> +               MAX77686_REG_32KHZ, max77686->mask, ~max77686->mask);
>> +}
>> +
>> +static int max77686_clk_is_enabled(struct clk_hw *hw)
>> +{
>> +       struct clk_max77686 *max77686;
>> +       int ret;
>> +       u32 val;
>> +
>> +       max77686 = get_max77686_clk(hw);
>> +       if (!max77686)
>> +               return -ENOMEM;
>> +
>> +       ret = regmap_read(max77686->iodev->regmap,
>> +                               MAX77686_REG_32KHZ, &val);
>> +
>> +       if (ret < 0)
>> +               return -EINVAL;
>> +
>> +       return val & max77686->mask;
>> +}
>> +
>> +static struct clk_ops clk_max77686_ops = {
>> +       .prepare        = max77686_clk_enable,
>> +       .unprepare      = max77686_clk_disable,
>> +       .is_enabled     = max77686_clk_is_enabled,
>> +};
>> +
>> +static int max77686_clk_register(struct device *dev,
>> +                               struct clk_max77686 *max77686, int clk_id)
>> +{
>> +       char clk_name[][10] = {"32khap", "32kcp", "p32kh"};
> const?

Okay, I agree that it is better to change definition into const.
>
>> +       struct clk *clk;
>> +
>> +       clk = clk_register(dev, clk_name[clk_id], &clk_max77686_ops,
>> +                               &max77686->hw, NULL, 0, CLK_IS_ROOT);
>> +
>> +       if (IS_ERR(clk))
>> +               return -ENOMEM;
>> +
>> +       max77686->lookup = devm_kzalloc(dev, sizeof(struct clk_lookup),
>> +                                       GFP_KERNEL);
>> +       if (IS_ERR(max77686->lookup))
>> +               return -ENOMEM;
>> +
>> +       max77686->lookup->con_id = clk_name[clk_id];
>> +       max77686->lookup->clk = clk;
>> +
>> +       clkdev_add(max77686->lookup);
>> +
>> +       return 0;
>> +}
>> +
>> +static __devinit int max77686_clk_probe(struct platform_device *pdev)
>> +{
>> +       struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);
>> +       struct clk_max77686 *max77686[MAX77686_CLKS_NUM];
>> +       int i, ret;
>> +
>> +       for (i = 0; i < MAX77686_CLKS_NUM; i++) {
>> +               max77686[i] = devm_kzalloc(&pdev->dev,
>> +                                sizeof(struct clk_max77686), GFP_KERNEL);
>> +               if (!max77686[i])
>> +                       return -ENOMEM;
>> +
>> +               max77686[i]->iodev = iodev;
>> +               max77686[i]->mask = 1 << i;
>> +
>> +               ret = max77686_clk_register(&pdev->dev, max77686[i], i);
>> +               if (ret) {
>> +                       dev_err(&pdev->dev, "Fail to register clock\n");
>> +                       return ret;
>> +               }
> There is a memory leak if you successfully register any clocks and then
> fail to register the others.  Be sure to unwind the loop and kfree those
> clocks in such a case (since this appears fatal).
I think it'll free memory allocation automatically, because It is used
devm_kzalloc. Am I wrong?

> You only have three clocks, so I think the loop could be completely
> replaced with an array and three calls to clk_register and clkdev_add
> (each).

Okay, I'll consider it.

Thanks and Best regard.
> Regards,
> Mike
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