linux-kernel - Re: [PATCH v10 char-misc-next 1/2] misc: microchip: pci1xxxx: Add support to read and write into PCI1XXXX OTP via NVMEM sysfs

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Message-ID: <50d10f649ac1314f07d53db89fe76c39e2764486.camel@microchip.com>
Date:   Thu, 27 Apr 2023 12:42:07 +0000
From:   <VaibhaavRam.TL@...rochip.com>
To:     <michael@...le.cc>
CC:     <gregkh@...uxfoundation.org>, <linux-gpio@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <UNGLinuxDriver@...rochip.com>,
        <arnd@...db.de>
Subject: Re: [PATCH v10 char-misc-next 1/2] misc: microchip: pci1xxxx: Add
 support to read and write into PCI1XXXX OTP via NVMEM sysfs

On Tue, 2023-04-25 at 09:33 +0200, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you
> know the content is safe
> 
> Hi,
> 
> > +static int pci1xxxx_otp_read(void *priv_t, unsigned int off,
> > +                          void *buf_t, size_t count)
> > +{
> > +     struct pci1xxxx_otp_eeprom_device *priv = priv_t;
> > +     void __iomem *rb = priv->reg_base;
> > +     char *buf = buf_t;
> > +     u32 regval;
> > +     u32 byte;
> > +     int ret;
> > +     u8 data;
> > +
> > +     if (off >= priv->nvmem_config_otp.size)
> > +             return -EFAULT;
> > +
> > +     if ((off + count) > priv->nvmem_config_otp.size)
> > +             count = priv->nvmem_config_otp.size - off;
> > +
> > +     ret = set_sys_lock(priv);
> > +     if (ret)
> > +             return ret;
> > +
> > +     for (byte = 0; byte < count; byte++) {
> > +             otp_device_set_address(priv, (u16)(off + byte));
> > +             data = readl(rb +
> > MMAP_OTP_OFFSET(OTP_FUNC_CMD_OFFSET));
> > +             writel(data | OTP_FUNC_RD_BIT,
> > +                    rb + MMAP_OTP_OFFSET(OTP_FUNC_CMD_OFFSET));
> > +             data = readl(rb +
> > MMAP_OTP_OFFSET(OTP_CMD_GO_OFFSET));
> > +             writel(data | OTP_CMD_GO_BIT,
> > +                    rb + MMAP_OTP_OFFSET(OTP_CMD_GO_OFFSET));
> > +
> > +             ret = read_poll_timeout(readl, regval,
> > +                                     !(regval &
> > OTP_STATUS_BUSY_BIT),
> > +                                     STATUS_READ_DELAY_US,
> > +                                     STATUS_READ_TIMEOUT_US, true,
> > +                                     rb +
> > MMAP_OTP_OFFSET(OTP_STATUS_OFFSET));
> > +
> > +             data = readl(rb +
> > MMAP_OTP_OFFSET(OTP_PASS_FAIL_OFFSET));
> > +             if (ret < 0 || data & OTP_FAIL_BIT)
> > +                     return -EIO;
> 
> Don't you need to release the lock?
Yes, release_sys_lock should be done. Will fix in next version of patch
> 
> > +
> > +             buf[byte] = readl(rb +
> > MMAP_OTP_OFFSET(OTP_RD_DATA_OFFSET));
> > +     }
> > +     release_sys_lock(priv);
> > +
> > +     return byte;
> > +}
>