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Message-Id: <20251006-gs101-pd-v1-4-f0cb0c01ea7b@linaro.org>
Date: Mon, 06 Oct 2025 17:43:30 +0100
From: André Draszik <andre.draszik@...aro.org>
To: Krzysztof Kozlowski <krzk@...nel.org>,
Alim Akhtar <alim.akhtar@...sung.com>, Rob Herring <robh@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Ulf Hansson <ulf.hansson@...aro.org>
Cc: Peter Griffin <peter.griffin@...aro.org>,
Tudor Ambarus <tudor.ambarus@...aro.org>,
Will McVicker <willmcvicker@...gle.com>, kernel-team@...roid.com,
linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-pm@...r.kernel.org,
André Draszik <andre.draszik@...aro.org>
Subject: [PATCH 04/10] pmdomain: samsung: convert to using regmap
On platforms such as Google gs101, direct mmio register access to the
PMU registers doesn't necessarily work and access must happen via a
(syscon) regmap created by the PMU driver instead.
In preparation for supporting such SoCs convert the existing mmio
accesses to using a regmap wrapper.
With this change in place, a follow-up patch can update the driver to
optionally acquire the PMU-created regmap without having to change the
rest of the code.
Signed-off-by: André Draszik <andre.draszik@...aro.org>
---
There is one checkpatch warning, relating to the non-const
regmap_config. It can a) not be made const without resorting to having
two copies and copying, and b) will go away in a follow-up patch
anyway.
---
drivers/pmdomain/samsung/exynos-pm-domains.c | 78 ++++++++++++++++++++--------
1 file changed, 57 insertions(+), 21 deletions(-)
diff --git a/drivers/pmdomain/samsung/exynos-pm-domains.c b/drivers/pmdomain/samsung/exynos-pm-domains.c
index f53e1bd2479807988f969774b4b7b4c5739c1aba..383126245811cb8e4dbae3b99ced3f06d3093f35 100644
--- a/drivers/pmdomain/samsung/exynos-pm-domains.c
+++ b/drivers/pmdomain/samsung/exynos-pm-domains.c
@@ -9,15 +9,14 @@
// conjunction with runtime-pm. Support for both device-tree and non-device-tree
// based power domain support is included.
-#include <linux/io.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pm_domain.h>
#include <linux/delay.h>
#include <linux/of.h>
-#include <linux/of_address.h>
#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
struct exynos_pm_domain_config {
/* Value for LOCAL_PWR_CFG and STATUS fields for each domain */
@@ -28,7 +27,7 @@ struct exynos_pm_domain_config {
* Exynos specific wrapper around the generic power domain
*/
struct exynos_pm_domain {
- void __iomem *base;
+ struct regmap *regmap;
struct generic_pm_domain pd;
u32 local_pwr_cfg;
};
@@ -36,31 +35,37 @@ struct exynos_pm_domain {
static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
{
struct exynos_pm_domain *pd;
- void __iomem *base;
u32 timeout, pwr;
- char *op;
+ int err;
pd = container_of(domain, struct exynos_pm_domain, pd);
- base = pd->base;
pwr = power_on ? pd->local_pwr_cfg : 0;
- writel_relaxed(pwr, base);
+ err = regmap_write(pd->regmap, 0, pwr);
+ if (err)
+ return err;
/* Wait max 1ms */
timeout = 10;
-
- while ((readl_relaxed(base + 0x4) & pd->local_pwr_cfg) != pwr) {
- if (!timeout) {
- op = (power_on) ? "enable" : "disable";
- pr_err("Power domain %s %s failed\n", domain->name, op);
- return -ETIMEDOUT;
+ while (timeout-- > 0) {
+ unsigned int val;
+
+ err = regmap_read(pd->regmap, 0x4, &val);
+ if (err || ((val & pd->local_pwr_cfg) != pwr)) {
+ cpu_relax();
+ usleep_range(80, 100);
+ continue;
}
- timeout--;
- cpu_relax();
- usleep_range(80, 100);
+
+ return 0;
}
- return 0;
+ if (!err)
+ err = -ETIMEDOUT;
+ pr_err("Power domain %s %sable failed: %d\n", domain->name,
+ power_on ? "en" : "dis", err);
+
+ return err;
}
static int exynos_pd_power_on(struct generic_pm_domain *domain)
@@ -109,8 +114,18 @@ static int exynos_pd_probe(struct platform_device *pdev)
struct device_node *np = dev->of_node;
struct of_phandle_args child, parent;
struct exynos_pm_domain *pd;
+ struct resource *res;
+ void __iomem *base;
+ unsigned int val;
int on, ret;
+ struct regmap_config reg_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+ .use_relaxed_mmio = true,
+ };
+
pm_domain_cfg = of_device_get_match_data(dev);
pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
if (!pd)
@@ -120,15 +135,36 @@ static int exynos_pd_probe(struct platform_device *pdev)
if (!pd->pd.name)
return -ENOMEM;
- pd->base = of_iomap(np, 0);
- if (!pd->base)
- return -ENODEV;
+ /*
+ * The resource typically points into the address space of the PMU.
+ * Therefore, avoid using devm_platform_get_and_ioremap_resource() and
+ * instead use platform_get_resource() and devm_ioremap() to avoid
+ * conflicts due to address space overlap.
+ */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return dev_err_probe(dev, -ENXIO, "missing IO resources");
+
+ base = devm_ioremap(dev, res->start, resource_size(res));
+ if (!base)
+ return dev_err_probe(dev, -ENOMEM,
+ "failed to ioremap PMU registers");
+
+ reg_config.max_register = resource_size(res) - reg_config.reg_stride;
+ pd->regmap = devm_regmap_init_mmio(dev, base, ®_config);
+ if (IS_ERR(pd->regmap))
+ return dev_err_probe(dev, PTR_ERR(base),
+ "failed to init regmap");
pd->pd.power_off = exynos_pd_power_off;
pd->pd.power_on = exynos_pd_power_on;
pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
- on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
+ ret = regmap_read(pd->regmap, 0x4, &val);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to read status");
+
+ on = val & pd->local_pwr_cfg;
pm_genpd_init(&pd->pd, NULL, !on);
ret = of_genpd_add_provider_simple(np, &pd->pd);
--
2.51.0.618.g983fd99d29-goog
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