On Mon, Feb 21, 2022 at 09:29:10PM +0300, Ivan Bornyakov wrote:
> Add OF reconfiguration notifier handler for WEIM bus to setup Chip
> Select timings on runtime creation of child devices.
>
> However, it is not possible to load another DT overlay with conflicting
> CS timings with previously loaded overlay, even if the first one is
> unloaded. The reason is that there is no acces to CS timing property of
> a device node being removed, thus we can't track which of configured CS
> are available for re-configuration.
>
> Signed-off-by: Ivan Bornyakov <[email protected]>
> ---
> Changelog:
> v1 -> v2: minor style fixes
> * rename "priv" -> weim_priv"
Sorry for not being clear on this, but I was suggesting something like
below.
struct weim_priv {
void __iomem *base;
struct cs_timing_state timing_state;
};
struct weim_priv *priv;
Shawn
> * remove excessive newline
>
> drivers/bus/imx-weim.c | 135 ++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 126 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
> index bccb275b65ba..80656d413750 100644
> --- a/drivers/bus/imx-weim.c
> +++ b/drivers/bus/imx-weim.c
> @@ -64,6 +64,11 @@ struct cs_timing_state {
> struct cs_timing cs[MAX_CS_COUNT];
> };
>
> +struct weim_data {
> + void __iomem *base;
> + struct cs_timing_state timing_state;
> +};
> +
> static const struct of_device_id weim_id_table[] = {
> /* i.MX1/21 */
> { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
> @@ -128,21 +133,26 @@ static int imx_weim_gpr_setup(struct platform_device *pdev)
> }
>
> /* Parse and set the timing for this device. */
> -static int weim_timing_setup(struct device *dev,
> - struct device_node *np, void __iomem *base,
> - const struct imx_weim_devtype *devtype,
> - struct cs_timing_state *ts)
> +static int weim_timing_setup(struct device *dev, struct device_node *np,
> + const struct imx_weim_devtype *devtype)
> {
> u32 cs_idx, value[MAX_CS_REGS_COUNT];
> int i, ret;
> int reg_idx, num_regs;
> struct cs_timing *cst;
> + struct weim_data *weim_priv;
> + struct cs_timing_state *ts;
> + void __iomem *base;
>
> if (WARN_ON(devtype->cs_regs_count > MAX_CS_REGS_COUNT))
> return -EINVAL;
> if (WARN_ON(devtype->cs_count > MAX_CS_COUNT))
> return -EINVAL;
>
> + weim_priv = dev_get_drvdata(dev);
> + base = weim_priv->base;
> + ts = &weim_priv->timing_state;
> +
> ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
> value, devtype->cs_regs_count);
> if (ret)
> @@ -189,14 +199,15 @@ static int weim_timing_setup(struct device *dev,
> return 0;
> }
>
> -static int weim_parse_dt(struct platform_device *pdev, void __iomem *base)
> +static int weim_parse_dt(struct platform_device *pdev)
> {
> const struct of_device_id *of_id = of_match_device(weim_id_table,
> &pdev->dev);
> const struct imx_weim_devtype *devtype = of_id->data;
> struct device_node *child;
> int ret, have_child = 0;
> - struct cs_timing_state ts = {};
> + struct weim_data *weim_priv;
> + void __iomem *base;
> u32 reg;
>
> if (devtype == &imx50_weim_devtype) {
> @@ -205,6 +216,9 @@ static int weim_parse_dt(struct platform_device *pdev, void __iomem *base)
> return ret;
> }
>
> + weim_priv = dev_get_drvdata(&pdev->dev);
> + base = weim_priv->base;
> +
> if (of_property_read_bool(pdev->dev.of_node, "fsl,burst-clk-enable")) {
> if (devtype->wcr_bcm) {
> reg = readl(base + devtype->wcr_offset);
> @@ -229,7 +243,7 @@ static int weim_parse_dt(struct platform_device *pdev, void __iomem *base)
> }
>
> for_each_available_child_of_node(pdev->dev.of_node, child) {
> - ret = weim_timing_setup(&pdev->dev, child, base, devtype, &ts);
> + ret = weim_timing_setup(&pdev->dev, child, devtype);
> if (ret)
> dev_warn(&pdev->dev, "%pOF set timing failed.\n",
> child);
> @@ -248,17 +262,25 @@ static int weim_parse_dt(struct platform_device *pdev, void __iomem *base)
>
> static int weim_probe(struct platform_device *pdev)
> {
> + struct weim_data *weim_priv;
> struct resource *res;
> struct clk *clk;
> void __iomem *base;
> int ret;
>
> + weim_priv = devm_kzalloc(&pdev->dev, sizeof(*weim_priv), GFP_KERNEL);
> + if (!weim_priv)
> + return -ENOMEM;
> +
> /* get the resource */
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> base = devm_ioremap_resource(&pdev->dev, res);
> if (IS_ERR(base))
> return PTR_ERR(base);
>
> + weim_priv->base = base;
> + dev_set_drvdata(&pdev->dev, weim_priv);
> +
> /* get the clock */
> clk = devm_clk_get(&pdev->dev, NULL);
> if (IS_ERR(clk))
> @@ -269,7 +291,7 @@ static int weim_probe(struct platform_device *pdev)
> return ret;
>
> /* parse the device node */
> - ret = weim_parse_dt(pdev, base);
> + ret = weim_parse_dt(pdev);
> if (ret)
> clk_disable_unprepare(clk);
> else
> @@ -278,6 +300,81 @@ static int weim_probe(struct platform_device *pdev)
> return ret;
> }
>
> +#if IS_ENABLED(CONFIG_OF_DYNAMIC)
> +static int of_weim_notify(struct notifier_block *nb, unsigned long action,
> + void *arg)
> +{
> + const struct imx_weim_devtype *devtype;
> + struct of_reconfig_data *rd = arg;
> + const struct of_device_id *of_id;
> + struct platform_device *pdev;
> + int ret = NOTIFY_OK;
> +
> + switch (of_reconfig_get_state_change(action, rd)) {
> + case OF_RECONFIG_CHANGE_ADD:
> + of_id = of_match_node(weim_id_table, rd->dn->parent);
> + if (!of_id)
> + return NOTIFY_OK; /* not for us */
> +
> + devtype = of_id->data;
> +
> + pdev = of_find_device_by_node(rd->dn->parent);
> + if (!pdev) {
> + pr_err("%s: could not find platform device for '%pOF'\n",
> + __func__, rd->dn->parent);
> +
> + return notifier_from_errno(-EINVAL);
> + }
> +
> + if (weim_timing_setup(&pdev->dev, rd->dn, devtype))
> + dev_warn(&pdev->dev,
> + "Failed to setup timing for '%pOF'\n", rd->dn);
> +
> + if (!of_node_check_flag(rd->dn, OF_POPULATED)) {
> + if (!of_platform_device_create(rd->dn, NULL, &pdev->dev)) {
> + dev_err(&pdev->dev,
> + "Failed to create child device '%pOF'\n",
> + rd->dn);
> + ret = notifier_from_errno(-EINVAL);
> + }
> + }
> +
> + platform_device_put(pdev);
> +
> + break;
> + case OF_RECONFIG_CHANGE_REMOVE:
> + if (!of_node_check_flag(rd->dn, OF_POPULATED))
> + return NOTIFY_OK; /* device already destroyed */
> +
> + of_id = of_match_node(weim_id_table, rd->dn->parent);
> + if (!of_id)
> + return NOTIFY_OK; /* not for us */
> +
> + pdev = of_find_device_by_node(rd->dn);
> + if (!pdev) {
> + dev_err(&pdev->dev,
> + "Could not find platform device for '%pOF'\n",
> + rd->dn);
> +
> + ret = notifier_from_errno(-EINVAL);
> + } else {
> + of_platform_device_destroy(&pdev->dev, NULL);
> + platform_device_put(pdev);
> + }
> +
> + break;
> + default:
> + break;
> + }
> +
> + return ret;
> +}
> +
> +struct notifier_block weim_of_notifier = {
> + .notifier_call = of_weim_notify,
> +};
> +#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
> +
> static struct platform_driver weim_driver = {
> .driver = {
> .name = "imx-weim",
> @@ -285,7 +382,27 @@ static struct platform_driver weim_driver = {
> },
> .probe = weim_probe,
> };
> -module_platform_driver(weim_driver);
> +
> +static int __init weim_init(void)
> +{
> +#if IS_ENABLED(CONFIG_OF_DYNAMIC)
> + WARN_ON(of_reconfig_notifier_register(&weim_of_notifier));
> +#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
> +
> + return platform_driver_register(&weim_driver);
> +}
> +module_init(weim_init);
> +
> +static void __exit weim_exit(void)
> +{
> +#if IS_ENABLED(CONFIG_OF_DYNAMIC)
> + of_reconfig_notifier_unregister(&weim_of_notifier);
> +#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
> +
> + return platform_driver_unregister(&weim_driver);
> +
> +}
> +module_exit(weim_exit);
>
> MODULE_AUTHOR("Freescale Semiconductor Inc.");
> MODULE_DESCRIPTION("i.MX EIM Controller Driver");
> --
> 2.34.1
>
>