[PATCH v3] soc/imx: Add GPCv2 power gating driver

From: Andrey Smirnov
Date: Mon Feb 20 2017 - 10:28:10 EST

Add code allowing for control of various power domains managed by GPCv2
IP block found in i.MX7 series of SoCs. Power domains covered by this
patch are:

- PCIE PHY
- MIPI PHY
- USB HSIC PHY
- USB OTG1/2 PHY

Support for any other power domain controlled by GPC is not present, and
can be added at some later point.

Testing of this code was done against a PCIe driver.

Cc: yurovsky@xxxxxxxxx
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---

Changes since v2 (see [v2]):

- Fix a critical bug where incorrect state of a bit was
expected in a busy wait loop (bit set instead of bit
cleared) imx7_gpc_pu_pgc_sw_pxx_req()

- Add missing step (setting of PCR in GPC_PGC_nCTRL) in power
down procedure

Changes since v1 (see [v1]):

- Various small DT bindings description fixes as per feedback
from Rob Herring


[v1] https://lkml.org/lkml/2017/2/6/554
[v2] https://lkml.org/lkml/2017/2/13/489

.../devicetree/bindings/power/fsl,imx-gpcv2.txt | 71 ++++
drivers/soc/imx/Makefile | 2 +-
drivers/soc/imx/gpcv2.c | 397 +++++++++++++++++++++
include/dt-bindings/power/imx7-power.h | 18 +
4 files changed, 487 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
create mode 100644 drivers/soc/imx/gpcv2.c
create mode 100644 include/dt-bindings/power/imx7-power.h

diff --git a/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
new file mode 100644
index 0000000..393f68a
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt
@@ -0,0 +1,71 @@
+Freescale i.MX General Power Controller v2
+==========================================
+
+The i.MX7S/D General Power Control (GPC) block contains Power Gating
+Control (PGC) for various power domains.
+
+Required properties:
+
+- compatible: Should be "fsl,imx7d-gpc"
+
+- reg: should be register base and length as documented in the
+ datasheet
+
+- interrupts: Should contain GPC interrupt request 1
+
+Power domains contained within GPC node are generic power domain
+providers, documented in
+Documentation/devicetree/bindings/power/power_domain.txt, which are
+described as subnodes of the power gating controller 'pgc' node,
+which, in turn, is expected to contain the following:
+
+Required properties:
+
+- reg: Power domain index. Valid values are defined in
+ include/dt-bindings/power/imx7-power.h
+
+- #power-domain-cells: Should be 0
+
+Optional properties:
+
+- power-supply: Power supply used to power the domain
+
+Example:
+
+ gpc: gpc@303a0000 {
+ compatible = "fsl,imx7d-gpc";
+ reg = <0x303a0000 0x1000>;
+ interrupt-controller;
+ interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
+ #interrupt-cells = <3>;
+ interrupt-parent = <&intc>;
+
+ pgc {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ pgc_pcie_phy: pgc-pcie-phy-domain {
+ #power-domain-cells = <0>;
+
+ reg = <IMX7_POWER_DOMAIN_PCIE_PHY>;
+ power-supply = <&reg_1p0d>;
+ };
+ };
+ };
+
+
+Specifying power domain for IP modules
+======================================
+
+IP cores belonging to a power domain should contain a 'power-domains'
+property that is a phandle for PGC node representing the domain.
+
+Example of a device that is part of the PCIE_PHY power domain:
+
+ pcie: pcie@0x33800000 {
+ reg = <0x33800000 0x4000>,
+ <0x4ff00000 0x80000>;
+ /* ... */
+ power-domains = <&pgc_pcie_phy>;
+ /* ... */
+ };
diff --git a/drivers/soc/imx/Makefile b/drivers/soc/imx/Makefile
index 35861f5..7bcc933 100644
--- a/drivers/soc/imx/Makefile
+++ b/drivers/soc/imx/Makefile
@@ -1 +1 @@
-obj-y += gpc.o
+obj-y += gpc.o gpcv2.o
diff --git a/drivers/soc/imx/gpcv2.c b/drivers/soc/imx/gpcv2.c
new file mode 100644
index 0000000..20f0515
--- /dev/null
+++ b/drivers/soc/imx/gpcv2.c
@@ -0,0 +1,397 @@
+/*
+ * Copyright 2017 Impinj, Inc
+ * Author: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
+ *
+ * Based on the code of analogus driver:
+ *
+ * Copyright 2015-2017 Pengutronix, Lucas Stach <kernel@xxxxxxxxxxxxxx>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <dt-bindings/power/imx7-power.h>
+
+#define GPC_PGC_CPU_MAPPING 0xec
+#define USB_HSIC_PHY_A7_DOMAIN BIT(6)
+#define USB_OTG2_PHY_A7_DOMAIN BIT(5)
+#define USB_OTG1_PHY_A7_DOMAIN BIT(4)
+#define PCIE_PHY_A7_DOMAIN BIT(3)
+#define MIPI_PHY_A7_DOMAIN BIT(2)
+
+#define GPC_PU_PGC_SW_PUP_REQ 0xf8
+#define GPC_PU_PGC_SW_PDN_REQ 0x104
+#define USB_HSIC_PHY_SW_Pxx_REQ BIT(4)
+#define USB_OTG2_PHY_SW_Pxx_REQ BIT(3)
+#define USB_OTG1_PHY_SW_Pxx_REQ BIT(2)
+#define PCIE_PHY_SW_Pxx_REQ BIT(1)
+#define MIPI_PHY_SW_Pxx_REQ BIT(0)
+
+#define GPC_MAX_REGISTER 0x1000
+
+#define GPC_PGC_nCTRL_PCR BIT(0)
+
+struct imx7_pgc_domain {
+ struct generic_pm_domain genpd;
+ struct regmap *regmap;
+ struct regulator *regulator;
+
+ unsigned int pgc_nctrl;
+
+ const struct {
+ u32 pxx;
+ u32 map;
+ } bits;
+
+ const int voltage;
+ struct device *dev;
+};
+
+static int imx7_gpc_pu_pgc_sw_pxx_req(struct generic_pm_domain *genpd,
+ bool on)
+{
+ int ret = 0;
+ unsigned long deadline;
+ struct imx7_pgc_domain *domain = container_of(genpd,
+ struct imx7_pgc_domain,
+ genpd);
+ unsigned int offset = (on) ?
+ GPC_PU_PGC_SW_PUP_REQ : GPC_PU_PGC_SW_PDN_REQ;
+
+ const bool has_regulator = !IS_ERR(domain->regulator);
+ const bool enable_power_control = domain->pgc_nctrl && !on;
+
+ regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+ domain->bits.map, domain->bits.map);
+ if (has_regulator && on) {
+ ret = regulator_enable(domain->regulator);
+ if (ret) {
+ dev_err(domain->dev, "failed to enable regulator\n");
+ goto unmap;
+ }
+ }
+
+ if (enable_power_control)
+ regmap_update_bits(domain->regmap, domain->pgc_nctrl,
+ GPC_PGC_nCTRL_PCR, GPC_PGC_nCTRL_PCR);
+
+
+ regmap_update_bits(domain->regmap, offset,
+ domain->bits.pxx, domain->bits.pxx);
+ /*
+ * As per "5.5.9.4 Example Code 4" in IMX7DRM.pdf wait
+ * for PUP_REQ/PDN_REQ bit to be cleared
+ */
+ deadline = jiffies + msecs_to_jiffies(1);
+ while (true) {
+ u32 pxx_req;
+
+ regmap_read(domain->regmap, offset, &pxx_req);
+
+ if (!(pxx_req & domain->bits.pxx))
+ break;
+
+ if (time_after(jiffies, deadline)) {
+ dev_err(domain->dev, "falied to command PGC\n");
+ ret = -ETIMEDOUT;
+ /*
+ * If we were in a process of enabling a
+ * domain and failed we might as well disable
+ * the regulator we just enabled. And if it
+ * was the opposite situation and we failed to
+ * power down -- keep the regulator on
+ */
+ on = !on;
+ break;
+ }
+
+ cpu_relax();
+ }
+
+ if (enable_power_control)
+ regmap_update_bits(domain->regmap, domain->pgc_nctrl,
+ GPC_PGC_nCTRL_PCR, 0);
+
+ if (has_regulator && !on) {
+ int err;
+
+ err = regulator_disable(domain->regulator);
+ if (err)
+ dev_err(domain->dev,
+ "failed to disable regulator: %d\n", ret);
+ /*
+ * Preserve earlier error code
+ */
+ ret = ret ?: err;
+ }
+unmap:
+ regmap_update_bits(domain->regmap, GPC_PGC_CPU_MAPPING,
+ domain->bits.map, 0);
+ return ret;
+}
+
+static int imx7_gpc_pu_pgc_sw_pup_req(struct generic_pm_domain *genpd)
+{
+ return imx7_gpc_pu_pgc_sw_pxx_req(genpd, true);
+}
+
+static int imx7_gpc_pu_pgc_sw_pdn_req(struct generic_pm_domain *genpd)
+{
+ return imx7_gpc_pu_pgc_sw_pxx_req(genpd, false);
+}
+
+static struct imx7_pgc_domain imx7_pgc_domains[] = {
+ [IMX7_POWER_DOMAIN_USB_HSIC_PHY] = {
+ .genpd = {
+ .name = "usb-hsic-phy",
+ .power_on = imx7_gpc_pu_pgc_sw_pup_req,
+ .power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+ },
+ .bits = {
+ .pxx = USB_HSIC_PHY_SW_Pxx_REQ,
+ .map = USB_HSIC_PHY_A7_DOMAIN,
+ },
+ .voltage = 1200000,
+ .pgc_nctrl = 0x0d00,
+ },
+
+ [IMX7_POWER_DOMAIN_USB_OTG2_PHY] = {
+ .genpd = {
+ .name = "usb-otg2-phy",
+ .power_on = imx7_gpc_pu_pgc_sw_pup_req,
+ .power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+ },
+ .bits = {
+ .pxx = USB_OTG2_PHY_SW_Pxx_REQ,
+ .map = USB_OTG2_PHY_A7_DOMAIN,
+ },
+ },
+
+ [IMX7_POWER_DOMAIN_USB_OTG1_PHY] = {
+ .genpd = {
+ .name = "usb-otg1-phy",
+ .power_on = imx7_gpc_pu_pgc_sw_pup_req,
+ .power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+ },
+ .bits = {
+ .pxx = USB_OTG1_PHY_SW_Pxx_REQ,
+ .map = USB_OTG1_PHY_A7_DOMAIN,
+ },
+ },
+
+ [IMX7_POWER_DOMAIN_PCIE_PHY] = {
+ .genpd = {
+ .name = "pcie-phy",
+ .power_on = imx7_gpc_pu_pgc_sw_pup_req,
+ .power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+ },
+ .bits = {
+ .pxx = PCIE_PHY_SW_Pxx_REQ,
+ .map = PCIE_PHY_A7_DOMAIN,
+ },
+ .voltage = 1000000,
+ .pgc_nctrl = 0x0c40,
+ },
+
+ [IMX7_POWER_DOMAIN_MIPI_PHY] = {
+ .genpd = {
+ .name = "mipi-phy",
+ .power_on = imx7_gpc_pu_pgc_sw_pup_req,
+ .power_off = imx7_gpc_pu_pgc_sw_pdn_req,
+ },
+ .bits = {
+ .pxx = MIPI_PHY_SW_Pxx_REQ,
+ .map = MIPI_PHY_A7_DOMAIN,
+ },
+ .voltage = 1000000,
+ .pgc_nctrl = 0x0c00,
+ },
+};
+
+static int imx7_pgc_domain_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+
+ if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
+ return 0;
+
+ domain->dev = &pdev->dev;
+
+ ret = pm_genpd_init(&domain->genpd, NULL, true);
+ if (ret) {
+ dev_err(domain->dev, "Failed to init power domain\n");
+ return ret;
+ }
+
+ domain->regulator = devm_regulator_get_optional(domain->dev, "power");
+ if (IS_ERR(domain->regulator) &&
+ PTR_ERR(domain->regulator) != -ENODEV) {
+ dev_err(domain->dev, "Failed to get domain's regulator\n");
+ return PTR_ERR(domain->regulator);
+ }
+
+ if (!IS_ERR(domain->regulator)) {
+ WARN_ON(!domain->voltage);
+ regulator_set_voltage(domain->regulator,
+ domain->voltage, domain->voltage);
+ }
+
+ ret = of_genpd_add_provider_simple(domain->dev->of_node,
+ &domain->genpd);
+ if (ret) {
+ dev_err(domain->dev, "Failed to add genpd provider\n");
+ pm_genpd_remove(&domain->genpd);
+ }
+
+ return ret;
+}
+
+static int imx7_pgc_domain_remove(struct platform_device *pdev)
+{
+ struct imx7_pgc_domain *domain = pdev->dev.platform_data;
+
+ if (IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) {
+ of_genpd_del_provider(domain->dev->of_node);
+ pm_genpd_remove(&domain->genpd);
+ }
+
+ return 0;
+}
+
+static const struct platform_device_id imx7_pgc_domain_id[] = {
+ { "imx7-pgc-domain", },
+ { },
+};
+
+static struct platform_driver imx7_pgc_domain_driver = {
+ .driver = {
+ .name = "imx7-pgc",
+ },
+ .probe = imx7_pgc_domain_probe,
+ .remove = imx7_pgc_domain_remove,
+ .id_table = imx7_pgc_domain_id,
+};
+builtin_platform_driver(imx7_pgc_domain_driver)
+
+static bool imx_gpcv2_readable_reg(struct device *dev, unsigned int reg)
+{
+ return reg % 4 == 0 &&
+ reg <= GPC_MAX_REGISTER;
+}
+
+static bool imx_gpcv2_volatile_reg(struct device *dev, unsigned int reg)
+{
+ return reg == GPC_PU_PGC_SW_PUP_REQ ||
+ reg == GPC_PU_PGC_SW_PDN_REQ;
+}
+
+static int imx_gpcv2_probe(struct platform_device *pdev)
+{
+ int ret;
+ void __iomem *base;
+ struct resource *res;
+ struct regmap *regmap;
+ struct device *dev = &pdev->dev;
+ struct device_node *pgc_np, *np;
+
+ static const struct regmap_config regmap_config = {
+ .cache_type = REGCACHE_FLAT,
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+
+ .readable_reg = imx_gpcv2_readable_reg,
+ .volatile_reg = imx_gpcv2_volatile_reg,
+
+ .max_register = GPC_MAX_REGISTER,
+ };
+
+ pgc_np = of_get_child_by_name(dev->of_node, "pgc");
+ if (!pgc_np) {
+ dev_err(dev, "No power domains specified in DT\n");
+ return -EINVAL;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ regmap = devm_regmap_init_mmio(dev, base, &regmap_config);
+ if (IS_ERR(regmap)) {
+ ret = PTR_ERR(regmap);
+ dev_err(dev, "failed to init regmap\n");
+ return ret;
+ }
+
+ for_each_child_of_node(pgc_np, np) {
+ u32 domain_index;
+ struct platform_device *pd_pdev;
+ struct imx7_pgc_domain *domain;
+
+ ret = of_property_read_u32(np, "reg", &domain_index);
+ if (ret) {
+ dev_err(dev, "Failed to read 'reg' property\n");
+ of_node_put(np);
+ return ret;
+ }
+
+ if (domain_index >= ARRAY_SIZE(imx7_pgc_domains)) {
+ dev_warn(dev,
+ "Domain index %d is out of bounds\n",
+ domain_index);
+ continue;
+ }
+
+ domain = &imx7_pgc_domains[domain_index];
+ domain->regmap = regmap;
+
+ pd_pdev = platform_device_alloc("imx7-pgc-domain",
+ domain_index);
+ if (!pd_pdev) {
+ dev_err(dev, "Failed to allocate platform device\n");
+ of_node_put(np);
+ return -ENOMEM;
+ }
+
+ pd_pdev->dev.platform_data = domain;
+ pd_pdev->dev.parent = dev;
+ pd_pdev->dev.of_node = np;
+
+ ret = platform_device_add(pd_pdev);
+ if (ret) {
+ platform_device_put(pd_pdev);
+ of_node_put(np);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static const struct of_device_id imx_gpcv2_dt_ids[] = {
+ { .compatible = "fsl,imx7d-gpc" },
+ { }
+};
+
+static struct platform_driver imx_gpc_driver = {
+ .driver = {
+ .name = "imx-gpcv2",
+ .of_match_table = imx_gpcv2_dt_ids,
+ },
+ .probe = imx_gpcv2_probe,
+};
+builtin_platform_driver(imx_gpc_driver)
diff --git a/include/dt-bindings/power/imx7-power.h b/include/dt-bindings/power/imx7-power.h
new file mode 100644
index 0000000..24dde62
--- /dev/null
+++ b/include/dt-bindings/power/imx7-power.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright  2017 Impinj
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __DT_BINDINGS_ARM_IMX7_POWER_H__
+#define __DT_BINDINGS_ARM_IMX7_POWER_H__
+
+#define IMX7_POWER_DOMAIN_USB_HSIC_PHY 0
+#define IMX7_POWER_DOMAIN_USB_OTG2_PHY 1
+#define IMX7_POWER_DOMAIN_USB_OTG1_PHY 2
+#define IMX7_POWER_DOMAIN_PCIE_PHY 3
+#define IMX7_POWER_DOMAIN_MIPI_PHY 4
+
+#endif
--
2.9.3