Re: [PATCH 1/2] hwmon: Add Synaptics AS370 PVT sensor driver
From: Guenter Roeck
Date: Mon Aug 26 2019 - 09:44:40 EST
On 8/26/19 3:01 AM, Jisheng Zhang wrote:
Add a new driver for Synaptics AS370 PVT sensors. Currently, only
temperature is supported.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx>
---
drivers/hwmon/Kconfig | 10 +++
drivers/hwmon/Makefile | 1 +
drivers/hwmon/as370-hwmon.c | 158 ++++++++++++++++++++++++++++++++++++
3 files changed, 169 insertions(+)
create mode 100644 drivers/hwmon/as370-hwmon.c
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 650dd71f9724..d31610933faa 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -246,6 +246,16 @@ config SENSORS_ADT7475
This driver can also be built as a module. If so, the module
will be called adt7475.
+config SENSORS_AS370
+ tristate "Synaptics AS370 SoC hardware monitoring driver"
I think this needs "depends on HAS_IOMEM".
+ help
+ If you say yes here you get support for the PVT sensors of
+ the Synaptics AS370 SoC
+
+ This driver can also be built as a module. If so, the module
+ will be called as370-hwmon.
+
+
config SENSORS_ASC7621
tristate "Andigilog aSC7621"
depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 8db472ea04f0..252e8a4c9781 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_SENSORS_ADT7475) += adt7475.o
obj-$(CONFIG_SENSORS_APPLESMC) += applesmc.o
obj-$(CONFIG_SENSORS_ARM_SCMI) += scmi-hwmon.o
obj-$(CONFIG_SENSORS_ARM_SCPI) += scpi-hwmon.o
+obj-$(CONFIG_SENSORS_AS370) += as370-hwmon.o
obj-$(CONFIG_SENSORS_ASC7621) += asc7621.o
obj-$(CONFIG_SENSORS_ASPEED) += aspeed-pwm-tacho.o
obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
diff --git a/drivers/hwmon/as370-hwmon.c b/drivers/hwmon/as370-hwmon.c
new file mode 100644
index 000000000000..98dfba45e1b0
--- /dev/null
+++ b/drivers/hwmon/as370-hwmon.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Synaptics AS370 SoC Hardware Monitoring Driver
+ *
+ * Copyright (C) 2018 Synaptics Incorporated
+ * Author: Jisheng Zhang <jszhang@xxxxxxxxxx>
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
Unnecessary include file.
+#include <linux/hwmon.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#define CTRL 0x0
+#define PD BIT(0)
+#define EN BIT(1)
+#define T_SEL BIT(2)
+#define V_SEL BIT(3)
+#define NMOS_SEL BIT(8)
+#define PMOS_SEL BIT(9)
+#define STS 0x4
+#define BN_MASK (0xfff << 0)
How about using GENMASK() ?
+#define EOC BIT(12)
+
+struct as370_hwmon {
+ void __iomem *base;
+};
+
+static void init_pvt(struct as370_hwmon *hwmon)
+{
+ u32 val;
+ void __iomem *addr = hwmon->base + CTRL;
+
+ val = PD;
+ writel_relaxed(val, addr);
+ val |= T_SEL;
+ val &= ~V_SEL;
+ val &= ~NMOS_SEL;
+ val &= ~PMOS_SEL;
What is the point of this ? We know that val == PD here.
+ writel_relaxed(val, addr);
+ val |= EN;
+ writel_relaxed(val, addr);
+ val &= ~PD;
+ writel_relaxed(val, addr);
+}
+
+static int read_pvt(struct as370_hwmon *hwmon)
+{
+ return readl_relaxed(hwmon->base + STS) & BN_MASK;
+}
Please fold into the calling code.
+
+static int as370_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *temp)
+{
+ int val;
+ struct as370_hwmon *hwmon = dev_get_drvdata(dev);
+
+ switch (attr) {
+ case hwmon_temp_input:
+ val = read_pvt(hwmon);
+ if (val < 0)
+ return val;
read_pvt() doesn't return a negative error code. This check is unnecessary.
+ *temp = val * 251802 / 4096 - 85525;
This results in rounding down the reported temperature. It is ok if it is
what you want; otherwise, I would suggest to use DIV_ROUND_CLOSEST().
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static umode_t
+as370_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ if (type != hwmon_temp)
+ return 0;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ return 0444;
+ default:
+ return 0;
+ }
+}
+
+static const u32 as370_hwmon_temp_config[] = {
+ HWMON_T_INPUT,
+ 0
+};
+
+static const struct hwmon_channel_info as370_hwmon_temp = {
+ .type = hwmon_temp,
+ .config = as370_hwmon_temp_config,
+};
+
+static const struct hwmon_channel_info *as370_hwmon_info[] = {
+ &as370_hwmon_temp,
+ NULL
+};
+
+static const struct hwmon_ops as370_hwmon_ops = {
+ .is_visible = as370_hwmon_is_visible,
+ .read = as370_hwmon_read,
+};
+
+static const struct hwmon_chip_info as370_chip_info = {
+ .ops = &as370_hwmon_ops,
+ .info = as370_hwmon_info,
+};
+
+static int as370_hwmon_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct device *hwmon_dev;
+ struct as370_hwmon *hwmon;
+ struct device *dev = &pdev->dev;
+
+ hwmon = devm_kzalloc(dev, sizeof(*hwmon), GFP_KERNEL);
+ if (!hwmon)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ hwmon->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(hwmon->base))
+ return PTR_ERR(hwmon->base);
+
+ init_pvt(hwmon);
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev,
+ "as370_hwmon",
The "_hwmon" seems unnecessary. It will show up in "sensors" as part
of the sensor name. Is this really what you want ?
+ hwmon,
+ &as370_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct of_device_id as370_hwmon_match[] = {
+ { .compatible = "syna,as370-hwmon" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, as370_hwmon_match);
+
+static struct platform_driver as370_hwmon_driver = {
+ .probe = as370_hwmon_probe,
+ .driver = {
+ .name = "as370-hwmon",
+ .of_match_table = as370_hwmon_match,
+ },
+};
+module_platform_driver(as370_hwmon_driver);
+
+MODULE_AUTHOR("Jisheng Zhang<jszhang@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Synaptics AS370 SoC hardware monitor");
+MODULE_LICENSE("GPL v2");