On Fri, Mar 4, 2011 at 12:00 AM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
> Why check for CONFIG_PANEL_LGPHILIPS_LB035Q02, but not for the lcd43?
>
> And is that even necessary? Of course it would make the kernel very
> slightly smaller if you leave some code out, but otherwise does that
> help? If you have the device definitions there, but the user doesn't
> load the driver, they wouldn't do anything, would they?
>
> For me the ifdefs just make the code harder to read, but I'm not sure if
> there's some standard custom to have these.
I agree that the size saving is minimal and the code is a bit more
difficult to read. My reason for the check was due to the fact that
the LG panel eats an SPI chip select.
SPI chip selects on Overo are a precious commodity. I wanted to
provide Overo users who don't use the LG panel an easy way to reclaim
that chip select (i.e. just turn off CONFIG_PANEL_LGPHILIPS_LB035Q02)
.
There is a subsequent patch queued that allows users to use the spidev
driver if they disable the LG panel driver (and similarly free up
another chip select by disabling the touchscreen controller):
diff --git a/arch/arm/mach-omap2/board-overo.c
b/arch/arm/mach-omap2/board-overo.c
index 463feaa..7974b9d 100644
--- a/arch/arm/mach-omap2/board-overo.c
+++ b/arch/arm/mach-omap2/board-overo.c
@@ -662,6 +662,14 @@ static struct spi_board_info
overo_spi_board_info[] __initdata = {
.irq = OMAP_GPIO_IRQ(OVERO_GPIO_PENDOWN),
.platform_data = &ads7846_config,
},
+#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
+ {
+ .modalias = "spidev",
+ .bus_num = 1,
+ .chip_select = 0,
+ .max_speed_hz = 48000000,
+ .mode = SPI_MODE_0,
+ },
#endif
#if defined(CONFIG_PANEL_LGPHILIPS_LB035Q02) || \
defined(CONFIG_PANEL_LGPHILIPS_LB035Q02_MODULE)
@@ -672,6 +680,14 @@ static struct spi_board_info
overo_spi_board_info[] __initdata = {
.max_speed_hz = 500000,
.mode = SPI_MODE_3,
},
+#elif defined(CONFIG_SPI_SPIDEV) || defined(CONFIG_SPI_SPIDEV_MODULE)
+ {
+ .modalias = "spidev",
+ .bus_num = 1,
+ .chip_select = 1,
+ .max_speed_hz = 48000000,
+ .mode = SPI_MODE_0,
+ },
#endif
};
The spidev driver turns out to be useful for a lot of embedded
applications, so I would prefer to leave the check in place if you
agree that this could be useful.
Regards,
Steve
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