From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Date: Wed, 27 Aug 2014 16:34:32 +0200 Subject: [U-Boot] [PATCH 23/23] ARM: tegra: Enable PCIe on Jetson TK1 In-Reply-To: <20140827132800.GA32243@ulmo> References: <1408346196-30419-1-git-send-email-thierry.reding@gmail.com> <1408346196-30419-24-git-send-email-thierry.reding@gmail.com> <53FC839A.7030108@nvidia.com> <20140827132800.GA32243@ulmo> Message-ID: <20140827143431.GD32243@ulmo> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wed, Aug 27, 2014 at 03:28:06PM +0200, Thierry Reding wrote: > On Tue, Aug 26, 2014 at 03:54:50PM +0300, Tuomas Tynkkynen wrote: > > On 18/08/14 10:16, Thierry Reding wrote: > > [...] > > > +static int as3722_gpio_direction_output(u8 gpio, u8 level) > > > +{ > > > + u8 value; > > > + int err; > > > + > > > + if (gpio > 7) > > > + return -EINVAL; > > > + > > > + if (level == 0) > > > + value = AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDL; > > > + else > > > + value = AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDH; > > > + > > > + err = as3722_write(AS3722_GPIO_CONTROL(gpio), value); > > > + if (err) { > > > + error("as3722: failed to configure GPIO#%u as output: %d\n", > > > + gpio, err); > > > + return err; > > > + } > > > + > > > + err = as3722_gpio_set(gpio, level); > > > + if (err < 0) { > > > + error("as3722: failed to set GPIO#%u high: %d\n", gpio, err); > > > + return err; > > > + } > > > + > > > + return 0; > > > +} > > > > This function doesn't work correctly if the GPIO was originally configured > > as inverted and low, which GPIO#2 seems to be. > > (as3722_read(AS3722_GPIO_CONTROL(2), &value) returns value == 0x87)... > > That should be equivalent to what we're setting but is a somewhat weird > default. I guess the fact that we're inverting it and then changing the > value to high in separate transactions makes the output flip twice. > > > > + > > > +int tegra_pcie_board_init(void) > > > +{ > > [...] > > > + > > > + err = as3722_gpio_direction_output(2, 1); > > > + if (err < 0) { > > > + error("as3722: failed to set GPIO#2 high: %d\n", err); > > > + return err; > > > + } > > [...] > > > > On my board, this call results in UART corruption, like this: > > > > tegra-pcie: non-prefetchable memory: 0x13000000-0x20000000 > > tegra-pcie: prefetchable memory: 0x20000000-0x40000000 > > ??????b????b2x1, 1x1 configuration > > ??5R?tegra-pcie: probing port 1, using 1 lanes > > > > Likely because GPIO#2 controls the +3.3V_LP0 rail, which powers the UART > > level shifters. Commenting the function call out fixes the corruption and > > PCI-E still works fine. > > If I add a udelay(500) after the above I'm not able to reproduce the > UART breakage anymore. But I guess making the AS3722 GPIO code smarter > would be helpful. In the kernel this is done by checking the invert bit > and then setting the value accordingly. I suppose the same could be done > for the mode bits. I'll see if I can work up a patch. How about this: -------------- next part -------------- diff --git a/drivers/power/as3722.c b/drivers/power/as3722.c index 59d1bf1b50b0..393dc8608d07 100644 --- a/drivers/power/as3722.c +++ b/drivers/power/as3722.c @@ -17,6 +17,7 @@ #define AS3722_GPIO_CONTROL(n) (0x08 + (n)) #define AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDH (1 << 0) #define AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDL (7 << 0) +#define AS3722_GPIO_CONTROL_MODE_MASK (7 << 0) #define AS3722_GPIO_CONTROL_INVERT (1 << 7) #define AS3722_LDO_VOLTAGE(n) (0x10 + (n)) #define AS3722_GPIO_SIGNAL_OUT 0x20 @@ -220,10 +221,21 @@ int as3722_gpio_direction_output(struct as3722 *pmic, unsigned int gpio, if (gpio > 7) return -EINVAL; + err = as3722_read(pmic, AS3722_GPIO_CONTROL(gpio), &value); + if (err < 0) { + error("failed to read GPIO#%u control register: %d", gpio, err); + return err; + } + + if (value & AS3722_GPIO_CONTROL_INVERT) + level = !level; + + value &= ~AS3722_GPIO_CONTROL_MODE_MASK; + if (level == 0) - value = AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDL; + value |= AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDL; else - value = AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDH; + value |= AS3722_GPIO_CONTROL_MODE_OUTPUT_VDDH; err = as3722_write(pmic, AS3722_GPIO_CONTROL(gpio), value); if (err) { -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 819 bytes Desc: not available URL: