Questions about mfd_add_devices and platform_data

[Lucas Tanure <tanure@xxxxxxxxx>]

Hi,

I would like to understand mfd_add_devices call and platform_data section.

All the drivers I read the platform_data is static, but mfd_add_devices will call platform_device_add_data which duplicates that memory and frees the first pointer given.
But the first pointer is static and kfrees says:

"Don't free memory not originally allocated by kmalloc() or you will run into trouble."

So, my questions is : Should my driver kmalloc platform_data first and then call mfd_add_devices ? Or it's fine to give static memory to it ?

Example driver:

drivers/mfd/vexpress-sysreg.c:

static struct syscon_platform_data vexpress_sysreg_sys_id_pdata = {
.label = "sys_id",
};

static struct mfd_cell vexpress_sysreg_cells[] = {
{
.name = "syscon",
.num_resources = 1,
.resources = (struct resource []) {
DEFINE_RES_MEM(SYS_ID, 0x4),
},
.platform_data = &vexpress_sysreg_sys_id_pdata,
.pdata_size = sizeof(vexpress_sysreg_sys_id_pdata),
},

For this case mfd_add_devices will free vexpress_sysreg_sys_id_pdata, but it's static.

Thanks
Lucas

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