[d-kernel] [PATCH 33/35] hwmon: baikal-pvt: support work on machines with old firmware

[Daniil Gnusarev <gnusarevda@basealt.ru>]

The first firmware versions used PVT channel indices, while
the latest versions have switched to direct addressing. Depending
on the presence of the "pvt_id" property in the DTS, the corresponding
addressing scheme is used.
Also, if the "clock-names" property is missing in the DTS, the value
25000000 / 21 is used instead of determining the operating frequency.
SMC32 calls are also used.

Signed-off-by: Daniil Gnusarev <gnusarevda@basealt.ru>
Do-not-upstream: this is a feature of Baikal-M
---
 drivers/hwmon/baikal-pvt-core.c            |  6 +++---
 drivers/hwmon/baikal-pvt.h                 |  1 +
 drivers/hwmon/bm1000-pvt-hwmon.c           | 11 ++++++++---
 include/linux/firmware/baikal/baikal-smc.h |  2 +-
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/hwmon/baikal-pvt-core.c b/drivers/hwmon/baikal-pvt-core.c
index 7a649b65768f72..2853a841135917 100644
--- a/drivers/hwmon/baikal-pvt-core.c
+++ b/drivers/hwmon/baikal-pvt-core.c
@@ -556,7 +556,7 @@ static int pvt_write_timeout(struct pvt_hwmon *pvt, long val)
 
 	rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
 	if (!rate)
-		return -ENODEV;
+		rate = 25000000 / 21;
 
 	/*
 	 * If alarms are enabled, the requested timeout must be divided
@@ -952,8 +952,8 @@ static int pvt_init_iface(struct pvt_hwmon *pvt)
 
 	rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
 	if (!rate) {
-		dev_err(pvt->dev, "Invalid reference clock rate\n");
-		return -ENODEV;
+		dev_warn(pvt->dev, "Invalid reference clock rate, default value is used\n");
+		rate = 25000000 / 21;
 	}
 
 	/*
diff --git a/drivers/hwmon/baikal-pvt.h b/drivers/hwmon/baikal-pvt.h
index ca1c786f872dfe..b419f847e67834 100644
--- a/drivers/hwmon/baikal-pvt.h
+++ b/drivers/hwmon/baikal-pvt.h
@@ -250,6 +250,7 @@ struct pvt_hwmon {
 	struct device *hwmon;
 
 	void __iomem *regs;
+	int pvt_id;
 	int irq;
 
 	struct clk_bulk_data clks[PVT_CLOCK_NUM];
diff --git a/drivers/hwmon/bm1000-pvt-hwmon.c b/drivers/hwmon/bm1000-pvt-hwmon.c
index 5b955da5996972..f355fce876037a 100644
--- a/drivers/hwmon/bm1000-pvt-hwmon.c
+++ b/drivers/hwmon/bm1000-pvt-hwmon.c
@@ -126,6 +126,9 @@ static int baikal_init_pvt(struct pvt_hwmon *pvt)
 		return -ENODEV;
 	pvt->regs = (void __iomem *)res->start;
 
+	pvt->pvt_id = -1;
+	of_property_read_u32(pvt->dev->of_node, "pvt_id", &(pvt->pvt_id));
+
 	return 0;
 }
 
@@ -133,9 +136,9 @@ static u32 baikal_read_pvt(struct pvt_hwmon *pvt, u32 reg)
 {
 	struct arm_smccc_res res;
 
-	arm_smccc_smc(BAIKAL_SMC_PVT_CMD, PVT_READ, (unsigned long)pvt->regs,
+	arm_smccc_smc(BAIKAL_SMC_PVT_CMD, PVT_READ,
+		      (pvt->pvt_id >= 0) ? (unsigned long)pvt->pvt_id : (unsigned long)pvt->regs,
 		      reg, 0, 0, 0, 0, &res);
-
 	return res.a0;
 }
 
@@ -143,7 +146,8 @@ static int baikal_write_pvt(struct pvt_hwmon *pvt, u32 reg, u32 data)
 {
 	struct arm_smccc_res res;
 
-	arm_smccc_smc(BAIKAL_SMC_PVT_CMD, PVT_WRITE, (unsigned long)pvt->regs,
+	arm_smccc_smc(BAIKAL_SMC_PVT_CMD, PVT_WRITE,
+		      (pvt->pvt_id >= 0) ? (unsigned long)pvt->pvt_id : (unsigned long)pvt->regs,
 		      reg, data, 0, 0, 0, &res);
 	return res.a0;
 }
@@ -183,6 +187,7 @@ static int pvt_probe(struct platform_device *pdev)
 
 static const struct of_device_id pvt_of_match[] = {
 	{ .compatible = "baikal,bm1000-pvt" },
+	{ .compatible = "baikal,pvt" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, pvt_of_match);
diff --git a/include/linux/firmware/baikal/baikal-smc.h b/include/linux/firmware/baikal/baikal-smc.h
index 648b1e9507de48..1ff7b775975238 100644
--- a/include/linux/firmware/baikal/baikal-smc.h
+++ b/include/linux/firmware/baikal/baikal-smc.h
@@ -9,7 +9,7 @@
 #include <linux/arm-smccc.h>
 
 #define BAIKALL_SIP_SMC_FAST_CALL_VAL(func_num) \
-	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_64, \
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL, ARM_SMCCC_SMC_32, \
 	ARM_SMCCC_OWNER_SIP, (func_num))
 
 #define BAIKAL_SMC_CMU_CMD		BAIKALL_SIP_SMC_FAST_CALL_VAL(0x0000)
-- 
2.42.2