On 19.12.2018 18:29, Rob Herring wrote:
> 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?
Hi Rob,
yep, I will fix this.
Thank you for your review and for pointing me to the right solution.
Michal
>
> 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
>>
