Skip to content

Commit

Permalink
bus: imx-weim: add DT overlay support for WEIM bus
Browse files Browse the repository at this point in the history 
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 <i.bornyakov@metrotek.ru>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
  • Loading branch information
Ivan Bornyakov authored and Shawn Guo committed Feb 22, 2022
1 parent 16dcfe9 commit e6cb540
Showing 1 changed file with 126 additions and 9 deletions.
135 changes: 126 additions & 9 deletions drivers/bus/imx-weim.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,6 +64,11 @@ struct cs_timing_state {
struct cs_timing cs[MAX_CS_COUNT];
};

struct weim_priv {
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, },
Expand Down Expand Up @@ -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_priv *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;

priv = dev_get_drvdata(dev);
base = priv->base;
ts = &priv->timing_state;

ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
value, devtype->cs_regs_count);
if (ret)
Expand Down Expand Up @@ -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_priv *priv;
void __iomem *base;
u32 reg;

if (devtype == &imx50_weim_devtype) {
Expand All @@ -205,6 +216,9 @@ static int weim_parse_dt(struct platform_device *pdev, void __iomem *base)
return ret;
}

priv = dev_get_drvdata(&pdev->dev);
base = 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);
Expand All @@ -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);
Expand All @@ -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_priv *priv;
struct resource *res;
struct clk *clk;
void __iomem *base;
int ret;

priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!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);

priv->base = base;
dev_set_drvdata(&pdev->dev, priv);

/* get the clock */
clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(clk))
Expand All @@ -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
Expand All @@ -278,14 +300,109 @@ 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",
.of_match_table = weim_id_table,
},
.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");
Expand Down

0 comments on commit e6cb540

Please sign in to comment.