diff mbox series

[4/4] ARM: mxs: cfa10036: Fixup OLED display reset polarity

Message ID 1543935806-94880-5-git-send-email-michal.vokac@ysoft.com (mailing list archive)
State New, archived
Headers show
Series Fix ssd1307fb OLED driver reset | expand

Commit Message

Michal Vokáč Dec. 4, 2018, 3:03 p.m. UTC
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@ysoft.com>
---
 arch/arm/mach-mxs/mach-mxs.c | 45 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

Comments

Rob Herring (Arm) Dec. 19, 2018, 5:29 p.m. UTC | #1
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@ysoft.com>
> ---
>  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@kernel.org>

> +		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
>
Michal Vokáč Dec. 20, 2018, 11:39 a.m. UTC | #2
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@ysoft.com>
>> ---
>>   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@kernel.org>
> 
>> +		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
>>
diff mbox series

Patch

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]);
+		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)