On Tue, Dec 04, 2018 at 03:03:40PM +0000, Vokáč Michal wrote:
> There was a bug in reset signal generation in ssd1307fb OLED driver.
> The display needs an active-low reset signal but the driver produced
> the correct sequence only if the GPIO used for reset was specified as
> GPIO_ACTIVE_HIGH.
>
> Now as the OLED driver is fixed it is also necessarry to implement
> a fixup for all current users of the old DT ABI. There is only one
> in-tree user and that is the Crystalfontz CFA-10036 board. In case
> this board is booting and GPIO_ACTIVE_HIGH is used for reset we
> override it to GPIO_ACTIVE_LOW.
>
> Signed-off-by: Michal Vokáč <michal.vokac@xxxxxxxxx>
> ---
> arch/arm/mach-mxs/mach-mxs.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/arch/arm/mach-mxs/mach-mxs.c b/arch/arm/mach-mxs/mach-mxs.c
> index 1c6062d..23c260c 100644
> --- a/arch/arm/mach-mxs/mach-mxs.c
> +++ b/arch/arm/mach-mxs/mach-mxs.c
> @@ -21,6 +21,7 @@
> #include <linux/reboot.h>
> #include <linux/micrel_phy.h>
> #include <linux/of_address.h>
> +#include <linux/of_gpio.h>
> #include <linux/of_platform.h>
> #include <linux/phy.h>
> #include <linux/pinctrl/consumer.h>
> @@ -268,9 +269,53 @@ static void __init apx4devkit_init(void)
> apx4devkit_phy_fixup);
> }
>
> +#define OLED_RESET_GPIO_LEN 3
> +#define OLED_RESET_GPIO_SIZE (OLED_RESET_GPIO_LEN * sizeof(u32))
> +
> +static void __init crystalfontz_oled_reset_fixup(void)
> +{
> + struct property *newgpio;
> + struct device_node *np;
> + u32 *gpiospec;
> + int i, ret;
> +
> + np = of_find_compatible_node(NULL, NULL, "solomon,ssd1306fb-i2c");
> + if (!np)
> + return;
> +
> + newgpio = kzalloc(sizeof(*newgpio) + OLED_RESET_GPIO_SIZE, GFP_KERNEL);
> + if (!newgpio)
> + return;
> +
> + newgpio->value = newgpio + 1;
> + newgpio->length = OLED_RESET_GPIO_SIZE;
> + newgpio->name = kstrdup("reset-gpios", GFP_KERNEL);
> + if (!newgpio->name) {
> + kfree(newgpio);
> + return;
> + }
> +
> + gpiospec = newgpio->value;
> + for (i = 0; i < OLED_RESET_GPIO_LEN; i++) {
> + ret = of_property_read_u32_index(np, "reset-gpios", i,
> + &gpiospec[i]);
Don't we have a helper to read the whole array?
Otherwise, for the series:
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> + if (ret) {
> + kfree(newgpio);
> + return;
> + }
> + }
> +
> + if (!(gpiospec[2] & OF_GPIO_ACTIVE_LOW)) {
> + gpiospec[2] |= OF_GPIO_ACTIVE_LOW;
> + cpu_to_be32_array(gpiospec, gpiospec, OLED_RESET_GPIO_LEN);
> + of_update_property(np, newgpio);
> + }
> +}
> +
> static void __init crystalfontz_init(void)
> {
> update_fec_mac_prop(OUI_CRYSTALFONTZ);
> + crystalfontz_oled_reset_fixup();
> }
>
> static void __init duckbill_init(void)
> --
> 2.1.4
>
