From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: =?UTF-8?q?Michal=20Vok=C3=A1=C4=8D?= Subject: [PATCH RESEND v2 4/4] ARM: mxs: cfa10036: Fixup OLED display reset polarity Date: Mon, 28 Jan 2019 12:53:03 +0100 Message-Id: <1548676383-29685-5-git-send-email-michal.vokac@ysoft.com> In-Reply-To: <1548676383-29685-1-git-send-email-michal.vokac@ysoft.com> References: <1548676383-29685-1-git-send-email-michal.vokac@ysoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: Bartlomiej Zolnierkiewicz Cc: Rob Herring , Shawn Guo , Fabio Estevam , Alexandre Belloni , Maxime Ripard , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, =?UTF-8?q?Michal=20Vok=C3=A1=C4=8D?= List-ID: 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. Reviewed-by: Rob Herring Signed-off-by: Michal Vokáč --- Changes from v1: - Add R-by from Rob - Use of_property_read_variable_u32_array to read the GPIO specifier array instead of reading it manualy in for cycle. (Rob) arch/arm/mach-mxs/mach-mxs.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/arch/arm/mach-mxs/mach-mxs.c b/arch/arm/mach-mxs/mach-mxs.c index 1c6062d..50038d6 100644 --- a/arch/arm/mach-mxs/mach-mxs.c +++ b/arch/arm/mach-mxs/mach-mxs.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -268,9 +269,52 @@ 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 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; + ret = of_property_read_variable_u32_array(np, "reset-gpios", gpiospec, + OLED_RESET_GPIO_LEN, 0); + + if (ret < 0) { + 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