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ARM: OMAP2+: Add function to read GPMC settings from device-tree 

Adds a function to read the various GPMC chip-select settings from
device-tree and store them in the gpmc_settings structure.

Update the GPMC device-tree binding documentation to describe these
options.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
This commit is contained in:
Jon Hunter 2013-02-20 15:53:12 -06:00
parent 3a544354d5
commit 8c8a777127
3 changed files with 65 additions and 0 deletions
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23
Documentation/devicetree/bindings/bus/ti-gpmc.txt
View File

@ -65,6 +65,29 @@ The following are only applicable to OMAP3+ and AM335x:
- gpmc,wr-access
- gpmc,wr-data-mux-bus
GPMC chip-select settings properties for child nodes. All are optional.
- gpmc,burst-length Page/burst length. Must be 4, 8 or 16.
- gpmc,burst-wrap Enables wrap bursting
- gpmc,burst-read Enables read page/burst mode
- gpmc,burst-write Enables write page/burst mode
- gpmc,device-nand Device is NAND
- gpmc,device-width Total width of device(s) connected to a GPMC
chip-select in bytes. The GPMC supports 8-bit
and 16-bit devices and so this property must be
1 or 2.
- gpmc,mux-add-data Address and data multiplexing configuration.
Valid values are 1 for address-address-data
multiplexing mode and 2 for address-data
multiplexing mode.
- gpmc,sync-read Enables synchronous read. Defaults to asynchronous
is this is not set.
- gpmc,sync-write Enables synchronous writes. Defaults to asynchronous
is this is not set.
- gpmc,wait-pin Wait-pin used by client. Must be less than
"gpmc,num-waitpins".
- gpmc,wait-on-read Enables wait monitoring on reads.
- gpmc,wait-on-write Enables wait monitoring on writes.
Example for an AM33xx board:

40
arch/arm/mach-omap2/gpmc.c
View File

@ -1187,6 +1187,46 @@ static struct of_device_id gpmc_dt_ids[] = {
};
MODULE_DEVICE_TABLE(of, gpmc_dt_ids);
/**
* gpmc_read_settings_dt - read gpmc settings from device-tree
* @np: pointer to device-tree node for a gpmc child device
* @p: pointer to gpmc settings structure
*
* Reads the GPMC settings for a GPMC child device from device-tree and
* stores them in the GPMC settings structure passed. The GPMC settings
* structure is initialised to zero by this function and so any
* previously stored settings will be cleared.
*/
void gpmc_read_settings_dt(struct device_node *np, struct gpmc_settings *p)
{
memset(p, 0, sizeof(struct gpmc_settings));
p->sync_read = of_property_read_bool(np, "gpmc,sync-read");
p->sync_write = of_property_read_bool(np, "gpmc,sync-write");
p->device_nand = of_property_read_bool(np, "gpmc,device-nand");
of_property_read_u32(np, "gpmc,device-width", &p->device_width);
of_property_read_u32(np, "gpmc,mux-add-data", &p->mux_add_data);
if (!of_property_read_u32(np, "gpmc,burst-length", &p->burst_len)) {
p->burst_wrap = of_property_read_bool(np, "gpmc,burst-wrap");
p->burst_read = of_property_read_bool(np, "gpmc,burst-read");
p->burst_write = of_property_read_bool(np, "gpmc,burst-write");
if (!p->burst_read && !p->burst_write)
pr_warn("%s: page/burst-length set but not used!\n",
__func__);
}
if (!of_property_read_u32(np, "gpmc,wait-pin", &p->wait_pin)) {
p->wait_on_read = of_property_read_bool(np,
"gpmc,wait-on-read");
p->wait_on_write = of_property_read_bool(np,
"gpmc,wait-on-write");
if (!p->wait_on_read && !p->wait_on_write)
pr_warn("%s: read/write wait monitoring not enabled!\n",
__func__);
}
}
static void __maybe_unused gpmc_read_timings_dt(struct device_node *np,
struct gpmc_timings *gpmc_t)
{

2
arch/arm/mach-omap2/gpmc.h
View File

@ -225,5 +225,7 @@ extern void gpmc_cs_free(int cs);
extern void omap3_gpmc_save_context(void);
extern void omap3_gpmc_restore_context(void);
extern int gpmc_configure(int cmd, int wval);
extern void gpmc_read_settings_dt(struct device_node *np,
struct gpmc_settings *p);
#endif