linux-kernel - Re: [PATCH RFC i2c-master] i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoint of pci1xxxx switch

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Message-ID: <972a65f01b0077940cb4728e1fbfd3ea28860176.camel@microchip.com>
Date:   Wed, 24 Aug 2022 13:52:36 +0000
From:   <Tharunkumar.Pasumarthi@...rochip.com>
To:     <linux-i2c@...r.kernel.org>, <christophe.jaillet@...adoo.fr>,
        <linux-kernel@...r.kernel.org>, <wsa@...nel.org>
CC:     <krzk@...nel.org>, <andriy.shevchenko@...ux.intel.com>,
        <robh@...nel.org>, <jarkko.nikula@...ux.intel.com>,
        <sven@...npeter.dev>, <jsd@...ihalf.com>,
        <semen.protsenko@...aro.org>, <rafal@...ecki.pl>,
        <UNGLinuxDriver@...rochip.com>, <olof@...om.net>, <arnd@...db.de>
Subject: Re: [PATCH RFC i2c-master] i2c: microchip: pci1xxxx: Add driver for
 I2C host controller in multifunction endpoint of pci1xxxx switch

On Tue, 2022-08-23 at 13:48 +0200, Christophe JAILLET wrote:
> Le 23/08/2022 à 16:56, Tharun Kumar P a écrit :
> > Microchip PCI1XXXX is an unmanaged PCIe3.1a Switch for Consumer,
> > Industrial and Automotive applications. This switch has multiple
> > downstream ports. In one of the Switch's Downstream port, there
> > is a multifunction endpoint for peripherals which includes an I2C
> > host controller. The I2C function in the endpoint operates at 100KHz,
> > 400KHz and 1 MHz and has buffer depth of 128 bytes.
> > This patch provides the I2C controller driver for the I2C endpoint
> > of the switch.
> > 
> > Signed-off-by: Tharun Kumar P <tharunkumar.pasumarthi@...rochip.com>
> > ---
> >   MAINTAINERS                            |    8 +
> >   drivers/i2c/busses/Kconfig             |   10 +
> >   drivers/i2c/busses/Makefile            |    1 +
> >   drivers/i2c/busses/i2c-mchp-pci1xxxx.c | 1123 ++++++++++++++++++++++++
> >   4 files changed, 1142 insertions(+)
> >   create mode 100644 drivers/i2c/busses/i2c-mchp-pci1xxxx.c
> 
> 
> > +static int pci1xxxx_i2c_probe_pci(struct pci_dev *pdev,
> > +                               const struct pci_device_id *ent)
> > +{
> > +     struct pci1xxxx_i2c *i2c;
> > +     int ret;
> > +
> > +     i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
> > +     if (!i2c)
> > +             return -ENOMEM;
> > +
> > +     pci_set_drvdata(pdev, i2c);
> > +
> > +     i2c->i2c_xfer_in_progress = false;
> > +
> > +     ret = pcim_enable_device(pdev);
> > +     if (ret)
> > +             return ret;
> > +
> > +     pci_set_master(pdev);
> > +
> > +     /* we are getting the base address of the SMB core. SMB core uses
> > +      * BAR0 and 32K is the size here pci_resource_len returns 32K by
> > +      * reading BAR0
> > +      */
> > +
> > +     ret = pcim_iomap_regions(pdev, BIT(0), pci_name(pdev));
> > +     if (ret < 0)
> > +             return -ENOMEM;
> > +
> > +     i2c->i2c_base = pcim_iomap_table(pdev)[0];
> > +
> > +     init_completion(&i2c->i2c_xfer_done);
> > +
> > +     pci1xxxx_i2c_init(i2c);
> > +
> > +     dev_info(&pdev->dev, "i2c clock freq: %d\n", i2c->freq);
> > +
> > +     ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     /*Register the isr. we are not using any isr flags here.*/
> > +     ret = devm_request_irq(&pdev->dev, pci_irq_vector(pdev, 0),
> > +                            pci1xxxx_i2c_isr, PCI1XXXX_IRQ_FLAGS,
> > +                            pci_name(pdev), i2c);
> > +     if (ret)
> > +             goto err_free_region;
> > +
> > +     i2c->adap = pci1xxxx_i2c_ops;
> > +     i2c->adap.class = I2C_CLASS_SPD;
> > +     i2c->adap.dev.parent = &pdev->dev;
> > +
> > +     snprintf(i2c->adap.name, sizeof(i2c->adap.name),
> > +              "MCHP PCI1xxxx i2c adapter at %s", pci_name(pdev));
> > +
> > +     i2c_set_adapdata(&i2c->adap, i2c);
> > +
> > +     ret = i2c_add_adapter(&i2c->adap);
> > +     if (ret) {
> > +             dev_err(&pdev->dev, "i2c add adapter failed = %d\n", ret);
> > +             pci1xxxx_i2c_shutdown(i2c);
> > +             goto err_free_region;
> > +     }
> > +
> > +     return 0;
> > +
> > +err_free_region:
> > +     pci_free_irq_vectors(pdev);
> 
> Should this also be part of the .remove function?

Yes, I will include this API in remove callback

> > +     return ret;
> > +}
> > +
> > +static void pci1xxxx_i2c_remove_pci(struct pci_dev *pdev)
> > +{
> > +     struct pci1xxxx_i2c *i2c = pci_get_drvdata(pdev);
> > +
> > +     i2c_del_adapter(&i2c->adap);
> > +     pci1xxxx_i2c_shutdown(i2c);
> > +}
> > +