[PATCH v3 2/2] can: m_can: add Bosch M_CAN controller support
Marc Kleine-Budde
mkl at pengutronix.de
Fri Jul 11 05:03:22 PDT 2014
On 07/11/2014 01:13 PM, Varka Bhadram wrote:
> On 07/11/2014 03:59 PM, Dong Aisheng wrote:
>
> (...)
>
>> +/* m_can private data structure */
>> +struct m_can_priv {
>> + struct can_priv can; /* must be the first member */
>> + struct napi_struct napi;
>> + struct net_device *dev;
>> + struct device *device;
>> + struct clk *hclk;
>> + struct clk *cclk;
>> + void __iomem *base;
>> + u32 irqstatus;
>> +
>> + /* message ram configuration */
>> + void __iomem *mram_base;
>> + struct mram_cfg mcfg[MRAM_CFG_NUM];
>> +};
>> +
>
> It will be good if we write the comments for the driver private structure
>
>> +static inline u32 m_can_read(const struct m_can_priv *priv, enum
>> m_can_reg reg)
>> +{
>> + return readl(priv->base + reg);
>> +}
>> +
>
> (...)
>
>> +static void free_m_can_dev(struct net_device *dev)
>> +{
>> + free_candev(dev);
>> +}
>> +
>
> Why do we need a separate function which calls a single function... :-)
To be symetric with alloc_m_can_dev()
>
>> +static struct net_device *alloc_m_can_dev(void)
>> +{
>> + struct net_device *dev;
>> + struct m_can_priv *priv;
>> +
>> + dev = alloc_candev(sizeof(struct m_can_priv), 1);
>
> sizeof(*priv)...?
>
>> + if (!dev)
>> + return NULL;
>
> Return value -ENOMEM ?
I'm okay with NULL, however if we want to return an arror value, it must
be ERR_PTR() wrapped.
>
>> +
>> + priv = netdev_priv(dev);
>> + netif_napi_add(dev, &priv->napi, m_can_poll, M_CAN_NAPI_WEIGHT);
>> +
>> + priv->dev = dev;
>> + priv->can.bittiming_const = &m_can_bittiming_const;
>> + priv->can.do_set_mode = m_can_set_mode;
>> + priv->can.do_get_berr_counter = m_can_get_berr_counter;
>> + priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
>> + CAN_CTRLMODE_LISTENONLY |
>> + CAN_CTRLMODE_BERR_REPORTING;
>> +
>> + return dev;
>> +}
>> +
>> +static int m_can_open(struct net_device *dev)
>> +{
>> + struct m_can_priv *priv = netdev_priv(dev);
>> + int err;
>> +
>> + err = clk_prepare_enable(priv->hclk);
>> + if (err)
>> + return err;
>> +
>> + err = clk_prepare_enable(priv->cclk);
>> + if (err)
>> + goto exit_disable_hclk;
>> +
>> + /* open the can device */
>> + err = open_candev(dev);
>> + if (err) {
>> + netdev_err(dev, "failed to open can device\n");
>> + goto exit_disable_cclk;
>> + }
>> +
>> + /* register interrupt handler */
>> + err = request_irq(dev->irq, m_can_isr, IRQF_SHARED, dev->name,
>> + dev);
>
> why don't we use devm_request_irq()...? If you use this no need to worry
> about freeing the irq
...because the IRQ is allocated during ifup and released during ifdown.
>
>> + if (err < 0) {
>> + netdev_err(dev, "failed to request interrupt\n");
>> + goto exit_irq_fail;
>> + }
>> +
>> + /* start the m_can controller */
>> + m_can_start(dev);
>> +
>> + can_led_event(dev, CAN_LED_EVENT_OPEN);
>> + napi_enable(&priv->napi);
>> + netif_start_queue(dev);
>> +
>> + return 0;
>> +
>> +exit_irq_fail:
>> + close_candev(dev);
>> +exit_disable_cclk:
>> + clk_disable_unprepare(priv->cclk);
>> +exit_disable_hclk:
>> + clk_disable_unprepare(priv->hclk);
>> + return err;
>> +}
>> +
>> +static void m_can_stop(struct net_device *dev)
>> +{
>> + struct m_can_priv *priv = netdev_priv(dev);
>> +
>> + /* disable all interrupts */
>> + m_can_disable_all_interrupts(priv);
>> +
>> + clk_disable_unprepare(priv->hclk);
>> + clk_disable_unprepare(priv->cclk);
>> +
>> + /* set the state as STOPPED */
>> + priv->can.state = CAN_STATE_STOPPED;
>> +}
>> +
>> +static int m_can_close(struct net_device *dev)
>> +{
>> + struct m_can_priv *priv = netdev_priv(dev);
>> +
>> + netif_stop_queue(dev);
>> + napi_disable(&priv->napi);
>> + m_can_stop(dev);
>> + free_irq(dev->irq, dev);
>
> not required when you use devm_request_irq()
No....see above.
>
>> + close_candev(dev);
>> + can_led_event(dev, CAN_LED_EVENT_STOP);
>> +
>> + return 0;
>> +}
>> +
>
> (...)
>
>> +
>> +static const struct of_device_id m_can_of_table[] = {
>> + { .compatible = "bosch,m_can", .data = NULL },
>
> we can simply give '0' . No need of .data = NULL. Things should be
> simple right.... :-)
.data should be a pointer, while "0" isn't. (Although 0 is valid C, we
don't want a integer 0 to initialize a pointer.) However, you can omit
.data = NULL completely. When initialzing via C99, any omited members of
the struct will automatically be initialized with 0x0. I like to see the
.data = NULL because it documents that there isn't any data (yet), once
another compatible is added, we need the .data anyways.
>
>> + { /* sentinel */ },
>> +};
>> +MODULE_DEVICE_TABLE(of, m_can_of_table);
>> +
>> +static int m_can_of_parse_mram(struct platform_device *pdev,
>> + struct m_can_priv *priv)
>> +{
>> + struct device_node *np = pdev->dev.of_node;
>> + struct resource *res;
>> + void __iomem *addr;
>> + u32 out_val[MRAM_CFG_LEN];
>> + int ret;
>> +
>> + /* message ram could be shared */
>> + res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>> "message_ram");
>> + if (!res)
>> + return -ENODEV;
>> +
>> + addr = devm_ioremap(&pdev->dev, res->start, resource_size(res));
>> + if (!addr)
>> + return -ENODEV;
>
> Is this err return is appropriate ... ?
-ENOMEM seems to be more commonly used.
>
>> +
>> + /* get message ram configuration */
>> + ret = of_property_read_u32_array(np, "mram-cfg",
>> + out_val, sizeof(out_val) / 4);
>> + if (ret) {
>> + dev_err(&pdev->dev, "can not get message ram configuration\n");
>> + return -ENODEV;
>> + }
>> +
>
> Is this err return is appropriate ... ?
Whay do you suggest?
>
>> + priv->mram_base = addr;
>> + priv->mcfg[MRAM_SIDF].off = out_val[0];
>> + priv->mcfg[MRAM_SIDF].num = out_val[1];
>> + priv->mcfg[MRAM_XIDF].off = priv->mcfg[MRAM_SIDF].off +
>> + priv->mcfg[MRAM_SIDF].num * SIDF_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_XIDF].num = out_val[2];
>> + priv->mcfg[MRAM_RXF0].off = priv->mcfg[MRAM_XIDF].off +
>> + priv->mcfg[MRAM_XIDF].num * XIDF_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_RXF0].num = out_val[3] & RXFC_FS_MASK;
>> + priv->mcfg[MRAM_RXF1].off = priv->mcfg[MRAM_RXF0].off +
>> + priv->mcfg[MRAM_RXF0].num * RXF0_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_RXF1].num = out_val[4] & RXFC_FS_MASK;
>> + priv->mcfg[MRAM_RXB].off = priv->mcfg[MRAM_RXF1].off +
>> + priv->mcfg[MRAM_RXF1].num * RXF1_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_RXB].num = out_val[5];
>> + priv->mcfg[MRAM_TXE].off = priv->mcfg[MRAM_RXB].off +
>> + priv->mcfg[MRAM_RXB].num * RXB_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_TXE].num = out_val[6];
>> + priv->mcfg[MRAM_TXB].off = priv->mcfg[MRAM_TXE].off +
>> + priv->mcfg[MRAM_TXE].num * TXE_ELEMENT_SIZE;
>> + priv->mcfg[MRAM_TXB].num = out_val[7] & TXBC_NDTB_MASK;
>> +
>> + dev_dbg(&pdev->dev, "mram_base %p sidf 0x%x %d xidf 0x%x %d rxf0
>> 0x%x %d rxf1 0x%x %d rxb 0x%x %d txe 0x%x %d txb 0x%x %d\n",
>> + priv->mram_base,
>> + priv->mcfg[MRAM_SIDF].off, priv->mcfg[MRAM_SIDF].num,
>> + priv->mcfg[MRAM_XIDF].off, priv->mcfg[MRAM_XIDF].num,
>> + priv->mcfg[MRAM_RXF0].off, priv->mcfg[MRAM_RXF0].num,
>> + priv->mcfg[MRAM_RXF1].off, priv->mcfg[MRAM_RXF1].num,
>> + priv->mcfg[MRAM_RXB].off, priv->mcfg[MRAM_RXB].num,
>> + priv->mcfg[MRAM_TXE].off, priv->mcfg[MRAM_TXE].num,
>> + priv->mcfg[MRAM_TXB].off, priv->mcfg[MRAM_TXB].num);
>> +
>
> dev_dbg() will insert the new lines in b/w. It wont print the values as
> you expected.
> Check this by enabling debug ...
What do you mean by b/w?
>
>> + return 0;
>> +}
>> +
>
> (...)
>
>> +
>> +static void unregister_m_can_dev(struct net_device *dev)
>> +{
>> + unregister_candev(dev);
>> +}
>> +
>
> again a function which calls a single func.
>
>> +static int m_can_plat_remove(struct platform_device *pdev)
>> +{
>> + struct net_device *dev = platform_get_drvdata(pdev);
>> +
>> + unregister_m_can_dev(dev);
>> + platform_set_drvdata(pdev, NULL);
>> +
>> + free_m_can_dev(dev);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct dev_pm_ops m_can_pmops = {
>> + SET_SYSTEM_SLEEP_PM_OPS(m_can_suspend, m_can_resume)
>> +};
>> +
>> +static struct platform_driver m_can_plat_driver = {
>> + .driver = {
>> + .name = KBUILD_MODNAME,
>> + .owner = THIS_MODULE,
>
> No need to update .owner. module_platform_driver() will do for you.
> see:http://lxr.free-electrons.com/source/include/linux/platform_device.h#L190
Oh, right.
>> + .of_match_table = of_match_ptr(m_can_of_table),
>> + .pm = &m_can_pmops,
>> + },
>> + .probe = m_can_plat_probe,
>> + .remove = m_can_plat_remove,
>> +};
>> +
>> +module_platform_driver(m_can_plat_driver);
>> +
>> +MODULE_AUTHOR("Dong Aisheng <b29396 at freescale.com>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("CAN bus driver for Bosch M_CAN controller");
>
>
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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