Re: [PATCH v24 04/12] mfd: psci-mfd: Add PSCI MFD driver for cpuidle-psci-domain cell

Update cpuidle-psci-domain to probe as an MFD child and use the parent
PSCI node for power-domain traversal.

Suggested-by: Bartosz Golaszewski <redacted>
Reviewed-by: Bartosz Golaszewski <redacted>
Signed-off-by: Shivendra Pratap <redacted>
---
 MAINTAINERS                           |  1 +
 drivers/cpuidle/Kconfig.arm           |  1 +
 drivers/cpuidle/cpuidle-psci-domain.c |  9 +-------
 drivers/mfd/Kconfig                   | 12 ++++++++++
 drivers/mfd/Makefile                  |  2 ++
 drivers/mfd/psci-mfd.c                | 43 +++++++++++++++++++++++++++++++++++
 6 files changed, 60 insertions(+), 8 deletions(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index fe67f7bfa44c..0b6e4f89f319 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -21671,6 +21671,7 @@ L:      linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:     Maintained
 F:     Documentation/devicetree/bindings/arm/psci.yaml
 F:     drivers/firmware/psci/
+F:     drivers/mfd/psci-mfd.c
 F:     include/linux/psci.h
 F:     include/uapi/linux/psci.h

diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm
index b88b01aa5829..c5ecca0d7397 100644
--- a/drivers/cpuidle/Kconfig.arm
+++ b/drivers/cpuidle/Kconfig.arm

@@ -36,6 +36,7 @@ config ARM_PSCI_CPUIDLE_DOMAIN
        bool "PSCI CPU idle Domain"
        depends on ARM_PSCI_CPUIDLE
        depends on PM_GENERIC_DOMAINS_OF
+       depends on MFD_PSCI
        select DT_IDLE_GENPD
        default y
        help

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index b9e4ad7d43a3..a2d01810f295 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c

@@ -17,7 +17,6 @@
 #include <linux/pm_runtime.h>
 #include <linux/psci.h>
 #include <linux/slab.h>
-#include <linux/string.h>

 #include "cpuidle-psci.h"
 #include "dt_idle_genpd.h"

@@ -122,14 +121,9 @@ static void psci_pd_remove(void)
        }
 }

-static const struct of_device_id psci_of_match[] = {
-       { .compatible = "arm,psci-1.0" },
-       {}
-};
-
 static int psci_cpuidle_domain_probe(struct platform_device *pdev)
 {
-       struct device_node *np = pdev->dev.of_node;
+       struct device_node *np = pdev->dev.parent->of_node;
        bool use_osi = psci_has_osi_support();
        int ret = 0, pd_count = 0;

@@ -181,7 +175,6 @@ static struct platform_driver psci_cpuidle_domain_driver = {
        .probe  = psci_cpuidle_domain_probe,
        .driver = {
                .name = "psci-cpuidle-domain",
-               .of_match_table = psci_of_match,
        },
 };

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index e4fd4572472f..d18655d76172 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig

@@ -2374,6 +2374,18 @@ config MFD_KHADAS_MCU
          additional drivers must be enabled in order to use the functionality
          of the device.

+config MFD_PSCI
+       bool "PSCI MFD for psci child cells"
+       depends on ARM_PSCI_FW
+       depends on OF
+       select MFD_CORE
+       default y
+       help
+         PSCI MFD registers PSCI child cells and exposes them as
+         platform devices. Child drivers are probed only if enabled in the
+         kernel configuration. Select this option whenever a supported PSCI
+         child driver is selected.
+
 config MFD_ACER_A500_EC
        tristate "Support for Acer Iconia Tab A500 Embedded Controller"
        depends on I2C

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 72d3944b0ad8..f3edfad702ff 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile

@@ -24,6 +24,8 @@ obj-$(CONFIG_MFD_EXYNOS_LPASS)        += exynos-lpass.o
 obj-$(CONFIG_MFD_GATEWORKS_GSC)        += gateworks-gsc.o
 obj-$(CONFIG_MFD_MACSMC)       += macsmc.o

+obj-$(CONFIG_MFD_PSCI)         += psci-mfd.o
+
 obj-$(CONFIG_MFD_TI_LP873X)    += lp873x.o
 obj-$(CONFIG_MFD_TI_LP87565)   += lp87565.o
 obj-$(CONFIG_MFD_TI_AM335X_TSCADC)     += ti_am335x_tscadc.o

diff --git a/drivers/mfd/psci-mfd.c b/drivers/mfd/psci-mfd.c
new file mode 100644
index 000000000000..7affd6bb09dd
--- /dev/null
+++ b/drivers/mfd/psci-mfd.c

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+static const struct mfd_cell psci_cells[] = {
+       {
+               .name = "psci-cpuidle-domain",
+       },
+};
+
+static int psci_mfd_probe(struct platform_device *pdev)
+{
+       return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, psci_cells,
+                                  ARRAY_SIZE(psci_cells), NULL, 0, NULL);
+}
+
+static const struct of_device_id psci_mfd_of_match[] = {
+       { .compatible = "arm,psci-1.0" },
+       { }
+};
+
+static struct platform_driver psci_mfd_driver = {
+       .probe = psci_mfd_probe,
+       .driver = {
+               .name = "psci-mfd",
+               .of_match_table = psci_mfd_of_match,
+       },
+};
+
+static int __init psci_mfd_init(void)
+{
+       return platform_driver_register(&psci_mfd_driver);
+}
+
+core_initcall(psci_mfd_init);
+
+MODULE_LICENSE("GPL");

--

2.34.1