Re: [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the NVMEM framework

Vladimir Zapolskiy
2016-03-02T22:08:23Z

Hi Andrew,

On 26.02.2016 21:59, Andrew Lunn wrote:
> Add a regmap for accessing the EEPROM, and then use that with the
> NVMEM framework. Enable backward compatibility in the NVMEM config
> structure, so that the 'eeprom' file in sys is provided by the
> framework.
>
> Signed-off-by: Andrew Lunn <andrew@lunn.ch>
> Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
> ---

[snip]

>
> static ssize_t
> -eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
> - struct bin_attribute *bin_attr,
> - char *buf, loff_t off, size_t count)
> +eeprom_93xx46_read(struct eeprom_93xx46_dev *edev, char *buf,
> + unsigned off, size_t count)
> {
> - struct eeprom_93xx46_dev *edev;
> - struct device *dev;
> ssize_t ret = 0;
>
> - dev = kobj_to_dev(kobj);
> - edev = dev_get_drvdata(dev);
> + if (unlikely(off >= edev->size))
> + return 0;
> + if ((off + count) > edev->size)
> + count = edev->size - off;
> + if (unlikely(!count))
> + return count;
>

I'm scratching my head, do you want to kind of revert
the change https://lkml.org/lkml/2015/7/26/89 ? Why?

If you know regmap_config.max_register, then all necessary
boundary checks can be done inside NVMEM core.

> mutex_lock(&edev->lock);
>
> @@ -226,16 +231,17 @@ eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
> }
>
> static ssize_t
> -eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
> - struct bin_attribute *bin_attr,
> - char *buf, loff_t off, size_t count)
> +eeprom_93xx46_write(struct eeprom_93xx46_dev *edev, const char *buf,
> + loff_t off, size_t count)
> {
> - struct eeprom_93xx46_dev *edev;
> - struct device *dev;
> int i, ret, step = 1;
>
> - dev = kobj_to_dev(kobj);
> - edev = dev_get_drvdata(dev);
> + if (unlikely(off >= edev->size))
> + return -EFBIG;
> + if ((off + count) > edev->size)
> + count = edev->size - off;
> + if (unlikely(!count))
> + return count;
>

See a comment above.

> /* only write even number of bytes on 16-bit devices */
> if (edev->addrlen == 6) {
> @@ -272,6 +278,49 @@ eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
> return ret ? : count;
> }
>
> +/*
> + * Provide a regmap interface, which is registered with the NVMEM
> + * framework
> +*/
> +static int eeprom_93xx46_regmap_read(void *context, const void *reg,
> + size_t reg_size, void *val,
> + size_t val_size)
> +{
> + struct eeprom_93xx46_dev *eeprom_93xx46 = context;
> + off_t offset = *(u32 *)reg;
> + int err;
> +
> + err = eeprom_93xx46_read(eeprom_93xx46, val, offset, val_size);
> + if (err)
> + return err;
> + return 0;

return eeprom_93xx46_read(eeprom_93xx46, val, offset, val_size);

> +}
> +
> +static int eeprom_93xx46_regmap_write(void *context, const void *data,
> + size_t count)
> +{
> + struct eeprom_93xx46_dev *eeprom_93xx46 = context;
> + const char *buf;
> + u32 offset;
> + size_t len;
> + int err;
> +
> + memcpy(&offset, data, sizeof(offset));
> + buf = (const char *)data + sizeof(offset);
> + len = count - sizeof(offset);
> +
> + err = eeprom_93xx46_write(eeprom_93xx46, buf, offset, len);
> + if (err)
> + return err;
> + return 0;

return eeprom_93xx46_write(eeprom_93xx46, buf, offset, len);

> +}
> +

--
With best wishes,
Vladimir