ARM: tegra: harmony: update PCI-e initialization sequence

On Harmony board PCI-e subsystem can be enabled only after certain
voltage regulators are on. One of the regulators is an internal
regulator on the PMIC and another one is controlled by a PMIC GPIO.
Addition of the voltage control to the Harmony PCI-e initialization
allows booting of kernel with CONFIG_TEGRA_PCI even if the PMIC driver
is not loaded. In this case the PCI-e initialization will fail
gracefully intead of hanging the system.
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/mach-tegra/board-harmony-pcie.c

@@ -27,13 +27,29 @@
 
 #ifdef CONFIG_TEGRA_PCI
 
+/* GPIO 3 of the PMIC */
+#define EN_VDD_1V05_GPIO	(TEGRA_NR_GPIOS + 2)
+
 static int __init harmony_pcie_init(void)
 {
+	struct regulator *regulator = NULL;
 	int err;
 
 	if (!machine_is_harmony())
 		return 0;
 
+	err = gpio_request(EN_VDD_1V05_GPIO, "EN_VDD_1V05");
+	if (err)
+		return err;
+
+	gpio_direction_output(EN_VDD_1V05_GPIO, 1);
+
+	regulator = regulator_get(NULL, "pex_clk");
+	if (IS_ERR_OR_NULL(regulator))
+		goto err_reg;
+
+	regulator_enable(regulator);
+
 	tegra_pinmux_set_tristate(TEGRA_PINGROUP_GPV, TEGRA_TRI_NORMAL);
 	tegra_pinmux_set_tristate(TEGRA_PINGROUP_SLXA, TEGRA_TRI_NORMAL);
 	tegra_pinmux_set_tristate(TEGRA_PINGROUP_SLXK, TEGRA_TRI_NORMAL);
@@ -49,9 +65,15 @@ static int __init harmony_pcie_init(void)
 	tegra_pinmux_set_tristate(TEGRA_PINGROUP_SLXA, TEGRA_TRI_TRISTATE);
 	tegra_pinmux_set_tristate(TEGRA_PINGROUP_SLXK, TEGRA_TRI_TRISTATE);
 
+	regulator_disable(regulator);
+	regulator_put(regulator);
+err_reg:
+	gpio_free(EN_VDD_1V05_GPIO);
+
 	return err;
 }
 
-subsys_initcall(harmony_pcie_init);
+/* PCI should be initialized after I2C, mfd and regulators */
+subsys_initcall_sync(harmony_pcie_init);
 
 #endif