Re: [PATCH v3] media: dvb: Provide 4 devm variants

[Marc Gonzalez]

On 21/07/2019 17:02, Ezequiel Garcia wrote:

> On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
>
>> Provide devm variants for automatic resource release on device removal.
>> Makes error-handling in probe() simpler, thus less error-prone.
>> Once all resources are devmanaged, remove() is no longer needed.
> 
> I think it would be better to add this API as part of a series
> that also uses it.

I have an outstanding RFC for a new driver:

        https://patchwork.kernel.org/patch/11040435/

Locally, I've updated the probe function to use the proposed devm functions.

I was mainly hoping to get initial feedback from the maintainers.
1) See if they're OK with devm APIs
2) See if they're OK with the way I implemented devm APIs
3) See what's missing to get an Ack

static int tsif_probe(struct platform_device *pdev)
{
        int err, virq;
        struct tsif *tsif;
        struct resource *res;
        struct dvb_frontend *fe;
        struct dvb_adapter *adap;
        struct device *dev = &pdev->dev;
        short num = DVB_UNSET;

        fe = dvb_get_demod_fe(dev->of_node);
        if (!fe)
                return -ENXIO;

        tsif = devm_kzalloc(dev, sizeof(*tsif), GFP_KERNEL);
        if (!tsif)
                return -ENOMEM;

        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsif0");
        tsif->base = devm_ioremap_resource(dev, res);
        if (IS_ERR(tsif->base))
                return PTR_ERR(tsif->base);

        virq = platform_get_irq_byname(pdev, "tsif0");
        err = devm_request_irq(dev, virq, tsif_isr, IRQF_SHARED, "tsif", tsif);
        if (err)
                return err;

        tsif->clk = devm_clk_get(dev, "iface");
        if (IS_ERR(tsif->clk))
                return PTR_ERR(tsif->clk);

        err = devm_clk_prepare_enable(dev, tsif->clk);
        if (err)
                return err;

        adap = &tsif->adapter;
        err = devm_dvb_register_adapter(dev, adap, "tsif", THIS_MODULE, &num);
        if (err) return err;

        /* Not sure the diff between filter and feed? */
        tsif->demux.filternum = 16; /*** Dunno what to put here ***/
        tsif->demux.feednum = 16;       /*** Dunno what to put here ***/
        tsif->demux.start_feed = noop;
        tsif->demux.stop_feed = noop;
        err = devm_dvb_dmx_init(dev, &tsif->demux);
        if (err) return err;

        /* What relation to dvb_demux.filternum??? */
        /* Do I need this object?? */
        tsif->dmxdev.filternum = 16;
        tsif->dmxdev.demux = &tsif->demux.dmx;
        err = devm_dvb_dmxdev_init(dev, &tsif->dmxdev, adap);
        if (err) return err;

        err = devm_dvb_register_frontend(dev, adap, fe);
        if (err) return err;

        writel_relaxed(TSIF_START + ENABLE_IRQ, tsif->base + TSIF_STS_CTL);
        devm_add_action(dev, stop_tsif, tsif);
        INIT_WORK(&tsif->work, handle_pkt);

        return 0;
}