[d-kernel] [PATCH 17/31] hwmon: bt1-pvt: adjusted probing for Baikal-M SoC

[Alexey Sheplyakov]

PVT registers and clocks are managed by the firmware (ARM-TF) and
can't be accessed by Linux directly. Therefore skip enabling
(disabling) clocks and ioremapping registers on Baikal-M.

Also a sensor is identified by special `pvt_id' instead of registers
base address. pvt_id is initialized from the device tree.

Signed-off-by: Alexey Sheplyakov <asheplyakov на basealt.ru>
X-feature-Baikal-M
---
 drivers/hwmon/Kconfig   |  5 +++--
 drivers/hwmon/bt1-pvt.c | 30 ++++++++++++++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index e70d9614bec2..b0417edd884c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -418,10 +418,11 @@ config SENSORS_ATXP1
 
 config SENSORS_BT1_PVT
 	tristate "Baikal-T1 Process, Voltage, Temperature sensor driver"
-	depends on MIPS_BAIKAL_T1 || COMPILE_TEST
+	depends on MIPS_BAIKAL_T1 || ARCH_BAIKAL || COMPILE_TEST
+	default m if MIPS_BAIKAL_T1 || ARCH_BAIKAL
 	select POLYNOMIAL
 	help
-	  If you say yes here you get support for Baikal-T1 PVT sensor
+	  If you say yes here you get support for Baikal-M or Baikal-T1 PVT sensor
 	  embedded into the SoC.
 
 	  This driver can also be built as a module. If so, the module will be
diff --git a/drivers/hwmon/bt1-pvt.c b/drivers/hwmon/bt1-pvt.c
index fa91be300c3b..90f29521f1af 100644
--- a/drivers/hwmon/bt1-pvt.c
+++ b/drivers/hwmon/bt1-pvt.c
@@ -927,6 +927,7 @@ static int pvt_request_regs(struct pvt_hwmon *pvt)
 {
 	struct platform_device *pdev = to_platform_device(pvt->dev);
 	struct resource *res;
+	int err = 0;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
@@ -934,27 +935,38 @@ static int pvt_request_regs(struct pvt_hwmon *pvt)
 		return -EINVAL;
 	}
 
+#ifdef BT1_PVT_DIRECT_REG_ACCESS
 	pvt->regs = devm_ioremap_resource(pvt->dev, res);
 	if (IS_ERR(pvt->regs))
 		return PTR_ERR(pvt->regs);
+#else
+	err = of_property_read_u32(pvt->dev->of_node, "pvt_id", &(pvt->pvt_id));
+	if (err) {
+		dev_err(pvt->dev, "couldn't find pvt_id\n");
+		return err;
+	}
+#endif
 
 	return 0;
 }
 
+#ifdef BT1_PVT_DIRECT_REG_ACCESS
 static void pvt_disable_clks(void *data)
 {
 	struct pvt_hwmon *pvt = data;
 
 	clk_bulk_disable_unprepare(PVT_CLOCK_NUM, pvt->clks);
 }
+#endif
 
 static int pvt_request_clks(struct pvt_hwmon *pvt)
 {
-	int ret;
+	int ret = 0;
 
 	pvt->clks[PVT_CLOCK_APB].id = "pclk";
 	pvt->clks[PVT_CLOCK_REF].id = "ref";
 
+#ifdef BT1_PVT_DIRECT_REG_ACCESS
 	ret = devm_clk_bulk_get(pvt->dev, PVT_CLOCK_NUM, pvt->clks);
 	if (ret) {
 		dev_err(pvt->dev, "Couldn't get PVT clocks descriptors\n");
@@ -972,8 +984,11 @@ static int pvt_request_clks(struct pvt_hwmon *pvt)
 		dev_err(pvt->dev, "Can't add PVT clocks disable action\n");
 		return ret;
 	}
-
-	return 0;
+#else
+	pvt->clks[PVT_CLOCK_APB].clk = NULL;
+	pvt->clks[PVT_CLOCK_REF].clk = NULL;
+#endif
+	return ret;
 }
 
 static int pvt_check_pwr(struct pvt_hwmon *pvt)
@@ -1013,14 +1028,17 @@ static int pvt_check_pwr(struct pvt_hwmon *pvt)
 
 static int pvt_init_iface(struct pvt_hwmon *pvt)
 {
-	unsigned long rate;
 	u32 trim, temp;
 
+#ifdef BT1_PVT_DIRECT_REG_ACCESS
+	unsigned long rate;
+
 	rate = clk_get_rate(pvt->clks[PVT_CLOCK_REF].clk);
 	if (!rate) {
 		dev_err(pvt->dev, "Invalid reference clock rate\n");
 		return -ENODEV;
 	}
+#endif
 
 	/*
 	 * Make sure all interrupts and controller are disabled so not to
@@ -1049,6 +1067,7 @@ static int pvt_init_iface(struct pvt_hwmon *pvt)
 	 * polled. In that case the formulae will look a bit different:
 	 *   Ttotal = 5 * (N / Fclk + Tmin)
 	 */
+#if defined(BT1_PVT_DIRECT_REG_ACCESS)
 #if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
 	pvt->timeout = ktime_set(PVT_SENSORS_NUM * PVT_TOUT_DEF, 0);
 	pvt->timeout = ktime_divns(pvt->timeout, rate);
@@ -1058,6 +1077,9 @@ static int pvt_init_iface(struct pvt_hwmon *pvt)
 	pvt->timeout = ktime_divns(pvt->timeout, rate);
 	pvt->timeout = ktime_add_ns(pvt->timeout, PVT_TOUT_MIN);
 #endif
+#else
+	pvt->timeout = ktime_set(0, PVT_TOUT_MIN * PVT_SENSORS_NUM);
+#endif
 
 	trim = PVT_TRIM_DEF;
 	if (!of_property_read_u32(pvt->dev->of_node,
-- 
2.33.3