| Message ID | 1329493468-7741-1-git-send-email-thierry.reding@avionic-design.de |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Fri, Feb 17, 2012 at 04:44:28PM +0100, Thierry Reding wrote: > + err = regulator_set_voltage(regulator, 3300000, 3300000); > + if (err < 0) > + goto err_put; > + This is a bit weird, why is this not just set by constraints? -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
* Mark Brown wrote: > On Fri, Feb 17, 2012 at 04:44:28PM +0100, Thierry Reding wrote: > > > + err = regulator_set_voltage(regulator, 3300000, 3300000); > > + if (err < 0) > > + goto err_put; > > + > > This is a bit weird, why is this not just set by constraints? I guess because I didn't know any better. I don't have access to the hardware right now, so it'll have to wait until Monday. I'll follow up with a patch after I've verified that setting via constraints works. Thierry
On Fri, Feb 17, 2012 at 08:16:05PM +0100, Thierry Reding wrote: > * Mark Brown wrote: > > This is a bit weird, why is this not just set by constraints? > I guess because I didn't know any better. I don't have access to the hardware > right now, so it'll have to wait until Monday. I'll follow up with a patch > after I've verified that setting via constraints works. OK. In general the expected idiom is that drivers will only use set_voltage() if they actually need to change the voltage at runtime, if they just need a single fixed voltage then the expectation is that either the board will boot in the correct configuration or the setup will be done by constraints. This replaces code with data (which is generally a good thing) and avoids issues with things like error handling when working with fixed voltage regulators.
diff --git a/arch/arm/mach-tegra/board-harmony-pcie.c b/arch/arm/mach-tegra/board-harmony-pcie.c index 33c4fed..d521cf4 100644 --- a/arch/arm/mach-tegra/board-harmony-pcie.c +++ b/arch/arm/mach-tegra/board-harmony-pcie.c @@ -45,6 +45,10 @@ static int __init harmony_pcie_init(void) if (IS_ERR_OR_NULL(regulator)) goto err_reg; + err = regulator_set_voltage(regulator, 3300000, 3300000); + if (err < 0) + goto err_put; + regulator_enable(regulator); err = tegra_pcie_init(true, true); @@ -55,6 +59,7 @@ static int __init harmony_pcie_init(void) err_pcie: regulator_disable(regulator); +err_put: regulator_put(regulator); err_reg: gpio_free(TEGRA_GPIO_EN_VDD_1V05_GPIO);
The PCIe reference clock needs a 3.3V supply voltage to work properly. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> --- This patch is based on next-20120217. Note that PCIe works without this patch when the Linux kernel is booted with a combination of QuickBoot and U-Boot because either apparently sets LD0 to 3.3V. This is not the case when booting from mainline U-Boot, so it must be set explicitly. arch/arm/mach-tegra/board-harmony-pcie.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)