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Commit 8c8a7771 authored by Jon Hunter's avatar Jon Hunter
Browse files

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: default avatarJon Hunter <jon-hunter@ti.com>
Tested-by: default avatarEzequiel Garcia <ezequiel.garcia@free-electrons.com>
parent 3a544354

Documentation/devicetree/bindings/bus/ti-gpmc.txt

+23 −0
Original line number Diff line number Diff line
@@ -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:

arch/arm/mach-omap2/gpmc.c

+40 −0
Original line number Diff line number Diff line
@@ -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)

{

arch/arm/mach-omap2/gpmc.h

+2 −0
Original line number Diff line number Diff line
@@ -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