Re: [RFC 1/2] ARM: Tegra: Device Tree Support: Update how sdhci devices are initialized

On Tue, May 10, 2011 at 3:03 PM, Stephen Warren [off-list ref] wrote:

John Bonesio wrote at Tuesday, May 10, 2011 2:14 PM:

quoted

This patch changes how sdhci devices are initialized so that a later

patch can

quoted

easily add support for i2c devies.

Signed-off-by: John Bonesio <bones-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>

quoted

@@ -134,6 +57,25 @@ static __initdata struct tegra_clk_init_table

tegra_dt_clk_init_table[] = {
      { NULL,         NULL,           0,              0},
 };

+static struct tegra_sdhci_platform_data sdhci_pdata1 = {
+     .cd_gpio        = -1,
+     .wp_gpio        = -1,
+     .power_gpio     = -1,
+};
+
+static struct tegra_sdhci_platform_data sdhci_pdata2 = {
+     .cd_gpio        = TEGRA_GPIO_SD2_CD,
+     .wp_gpio        = TEGRA_GPIO_SD2_WP,
+     .power_gpio     = TEGRA_GPIO_SD2_POWER,
+};
+
+static struct tegra_sdhci_platform_data sdhci_pdata4 = {
+     .cd_gpio        = TEGRA_GPIO_SD4_CD,
+     .wp_gpio        = TEGRA_GPIO_SD4_WP,
+     .power_gpio     = TEGRA_GPIO_SD4_POWER,
+     .is_8bit        = 1,
+};
+

So I understand why board-dt is itself registering the SDHCI platform
devices itself; so that the pdev initialization path is identical
between fully hard-coded boards and board-dt.c.

However, I'm surprised that we would include the platform data for
those devices within that argument; if we do that, we'll end up needing
different platform data for every board, and devicetree won't have
bought us anything.

In other words, I understood that board-dt would register all the
platform devices within Tegra, but not set up any of the plataform
data, and the device drivers for those devices would be updated to
get their platform data from devicetree if available, then fall back
to old-style platform data. In other words, the way the SDHCI drivers
work today in the devicetree/test branch.

If my understanding is correct, shouldn't the chunk above and the
one below be removed?

That's if we cut everything over, I think. until then, this code should fill
in the platform_device and register it. But the values should come from the
device tree, and it should only register the controllers that are in the
tree (and not marked as disabled).


-Olof