[U-Boot] nand_plat extensions with GPIO framework

[U-Boot] nand_plat extensions with GPIO framework

[Mike Frysinger]

i'm in the process of merging the GPIO layer from Linux into the Blackfin port 
(well, it's already done, so now i'm just converting drivers over to it).  as 
i'm sure you're aware, the GPIO framework in Linux provides a common API 
across all ports, so anyone who supports asm/gpio.h is going to work.  no-arch 
specific junk here.

some Blackfin boards use GPIOs with the nand_plat driver for the dev_ready 
pin.  so while i can easily convert the board config header to call these gpio 
funcs, the issue is that i cant really pull in headers like asm/gpio.h in the 
board config since all files will then pull it in.

what i'm thinking is something like this:
--- a/drivers/mtd/nand/nand_plat.c
+++ b/drivers/mtd/nand/nand_plat.c
@@ -16,6 +16,10 @@
 
 #include <common.h>
 #include <asm/io.h>
+#ifdef NAND_PLAT_GPIO_DEV_READY
+# include <asm/gpio.h>
+# define NAND_PLAT_DEV_READY(chip) gpio_get_value(NAND_PLAT_GPIO_DEV_READY)
+#endif
 
 #include <nand.h>
 
@@ -43,7 +47,14 @@ static int plat_dev_ready(struct mtd_info *mtd)
 
 int board_nand_init(struct nand_chip *nand)
 {
+#ifdef NAND_PLAT_GPIO_DEV_READY
+	gpio_request(NAND_PLAT_GPIO_DEV_READY, "nand-plat");
+	gpio_direction_input(NAND_PLAT_GPIO_DEV_READY);
+#endif
+
+#ifdef NAND_PLAT_INIT
 	NAND_PLAT_INIT();
+#endif
 
 	nand->cmd_ctrl = plat_cmd_ctrl;
 	nand->dev_ready = plat_dev_ready;

now the Blackfin boards merely have to do:
#define NAND_PLAT_GPIO_DEV_READY       GPIO_PF12
 
any suggestions about how to approach this ?
-mike
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[U-Boot] nand_plat extensions with GPIO framework

[Thomas Chou]

Mike Frysinger wrote:
> i'm in the process of merging the GPIO layer from Linux into the Blackfin port 
> (well, it's already done, so now i'm just converting drivers over to it).  as 
> i'm sure you're aware, the GPIO framework in Linux provides a common API 
> across all ports, so anyone who supports asm/gpio.h is going to work.  no-arch 
> specific junk here.
> 
> some Blackfin boards use GPIOs with the nand_plat driver for the dev_ready 
> pin.  so while i can easily convert the board config header to call these gpio 
> funcs, the issue is that i cant really pull in headers like asm/gpio.h in the 
> board config since all files will then pull it in.
> 

Hi Mike,

Thanks. This is what I have been looking for. Nios2 has asm/gpio.h 
already, then I added gpio_request() and tested on my boards.

Tested-by: Thomas Chou <thomas@wytron.com.tw>

[U-Boot] nand_plat extensions with GPIO framework

[Mike Frysinger]

On Tuesday, June 08, 2010 20:58:50 Thomas Chou wrote:
> Thanks. This is what I have been looking for. Nios2 has asm/gpio.h
> already, then I added gpio_request() and tested on my boards.

i couldnt seem to find anyone else who had imported asm/gpio.h yet, but i 
guess  was looking in the wrong place.  i have generic GPIO implementations 
pending for:
	- command line 'gpio' to toggle/set/clear pins
	- soft i2c via gpio
	- i had a status led gpio, but i'll convert to your version
	- examples for doing parallel flash with GPIO-assisted address lines

i'll try and generalize them a bit more and send thing out.  not sure if 
you'll find any of these useful though.
-mike
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[U-Boot] nand_plat extensions with GPIO framework

[Thomas Chou]

Mike Frysinger wrote:
> i'll try and generalize them a bit more and send thing out.  not sure if 
> you'll find any of these useful though.
> -mike

Hi Mike,

I believe it will be very useful. We are using gpio for led, key switch, 
i2c, nand flash status and other bit-oriented i/o.

Cheers,
Thomas