Re: [PATCH v6 3/3] thermal: zx2967: add thermal driver for ZTE's zx2967 family
From: Mathieu Poirier
Date: Thu Feb 02 2017 - 11:56:42 EST
On Thu, Feb 02, 2017 at 11:08:06PM +0800, Baoyou Xie wrote:
> This patch adds thermal driver for ZTE's zx2967 family.
>
> Signed-off-by: Baoyou Xie <baoyou.xie@xxxxxxxxxx>
> ---
> drivers/thermal/Kconfig | 8 ++
> drivers/thermal/Makefile | 1 +
> drivers/thermal/zx2967_thermal.c | 265 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 274 insertions(+)
> create mode 100644 drivers/thermal/zx2967_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 18f2de6..f64bd50 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -444,4 +444,12 @@ config BCM2835_THERMAL
> help
> Support for thermal sensors on Broadcom bcm2835 SoCs.
>
> +config ZX2967_THERMAL
> + tristate "Thermal sensors on zx2967 SoC"
> + depends on ARCH_ZX || COMPILE_TEST
> + help
> + Enable the zx2967 thermal sensors driver, which supports
> + the primitive temperature sensor embedded in zx2967 SoCs.
> + This sensor generates the real time die temperature.
> +
> endif
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 677c6d9..c00c05e 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -57,3 +57,4 @@ obj-$(CONFIG_HISI_THERMAL) += hisi_thermal.o
> obj-$(CONFIG_MTK_THERMAL) += mtk_thermal.o
> obj-$(CONFIG_GENERIC_ADC_THERMAL) += thermal-generic-adc.o
> obj-$(CONFIG_BCM2835_THERMAL) += bcm2835_thermal.o
> +obj-$(CONFIG_ZX2967_THERMAL) += zx2967_thermal.o
> diff --git a/drivers/thermal/zx2967_thermal.c b/drivers/thermal/zx2967_thermal.c
> new file mode 100644
> index 0000000..d8642cf
> --- /dev/null
> +++ b/drivers/thermal/zx2967_thermal.c
> @@ -0,0 +1,265 @@
> +/*
> + * ZTE's zx2967 family thermal sensor driver
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou.xie@xxxxxxxxxx>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/thermal.h>
> +
> +/* Power Mode: 0->low 1->high */
> +#define ZX2967_THERMAL_POWER_MODE 0
> +
> +/* DCF Control Register */
> +#define ZX2967_THERMAL_DCF 0x4
> +
> +/* Selection Register */
> +#define ZX2967_THERMAL_SEL 0x8
> +
> +/* Control Register */
> +#define ZX2967_THERMAL_CTRL 0x10
> +
> +#define ZX2967_THERMAL_READY 0x1000
> +#define ZX2967_THERMAL_TEMP_MASK 0xfff
> +#define ZX2967_THERMAL_ID_MASK 0x18
> +#define ZX2967_THERMAL_ID0 0x8
> +#define ZX2967_THERMAL_ID1 0x10
> +
> +struct zx2967_thermal_sensor {
> + struct zx2967_thermal_priv *priv;
> + struct thermal_zone_device *tzd;
> + int id;
> +};
> +
> +#define NUM_SENSORS 1
> +
> +struct zx2967_thermal_priv {
> + struct zx2967_thermal_sensor sensors[NUM_SENSORS];
Do we really need an array here if there's only 1 sensor?
> + /* Prevents reads sensor in parallel */
> + struct mutex lock;
> + struct clk *clk_gate;
> + struct clk *pclk;
> + s32 slope;
> + s32 offset;
> + void __iomem *regs;
> + struct device *dev;
> +};
Please add proper kernel style documentation for both structure. And as far as
I can tell the stuctures could be merged into a single one.
> +
> +static int zx2967_thermal_suspend(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> +
> + if (priv && priv->pclk)
> + clk_disable_unprepare(priv->pclk);
> +
> + if (priv && priv->clk_gate)
> + clk_disable_unprepare(priv->clk_gate);
> +
> + return 0;
> +}
> +
> +static int zx2967_thermal_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> + int error;
> +
> + error = clk_prepare_enable(priv->clk_gate);
> + if (error)
> + return error;
> +
> + error = clk_prepare_enable(priv->pclk);
> + if (error) {
> + clk_disable_unprepare(priv->clk_gate);
> + return error;
> + }
> +
> + return 0;
> +}
The above two function need to be enclosed with CONFIG_PM_SLEEP. Have a look at
other drivers that are using SIMPLE_DEV_PM_OPS.
> +
> +static int zx2967_thermal_get_temp(void *data, int *temp)
> +{
> + void __iomem *regs;
> + struct zx2967_thermal_sensor *sensor = data;
> + struct zx2967_thermal_priv *priv = sensor->priv;
> + unsigned long timeout = jiffies + msecs_to_jiffies(100);
> + u32 val, sel_id;
> +
> + regs = priv->regs;
> + mutex_lock(&priv->lock);
> +
> + writel_relaxed(0, regs + ZX2967_THERMAL_POWER_MODE);
> + writel_relaxed(2, regs + ZX2967_THERMAL_DCF);
> +
> + val = readl_relaxed(regs + ZX2967_THERMAL_SEL);
> + val &= ~ZX2967_THERMAL_ID_MASK;
> + sel_id = sensor->id ? ZX2967_THERMAL_ID0 : ZX2967_THERMAL_ID1;
> + val |= sel_id;
> + writel_relaxed(val, regs + ZX2967_THERMAL_SEL);
> +
> + usleep_range(100, 300);
Polling (like below) can't be use here? If not provide a good explanation as to
why that is the case.
> + val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
> + while (!(val & ZX2967_THERMAL_READY)) {
> + if (time_after(jiffies, timeout)) {
> + dev_err(priv->dev, "Thermal sensor %d data timeout\n",
> + sensor->id);
> + mutex_unlock(&priv->lock);
> + return -ETIMEDOUT;
> + }
> + usleep_range(100, 300);
> + val = readl_relaxed(regs + ZX2967_THERMAL_CTRL);
> + }
See if you can use readx_poll_timeout()
> +
> + writel_relaxed(3, regs + ZX2967_THERMAL_DCF);
> + val = readl_relaxed(regs + ZX2967_THERMAL_CTRL)
> + & ZX2967_THERMAL_TEMP_MASK;
> + writel_relaxed(1, regs + ZX2967_THERMAL_POWER_MODE);
Please add a #define (along with an explanation) for the values used with
writel_relaxed(). Otherwise reviewers are left guessing.
> +
> + /* Calculate temperature */
> + *temp = DIV_ROUND_CLOSEST(((s32)val + priv->offset) * 1000,
> + priv->slope);
Same here, I have to guess why 1000 is used.
> +
> + mutex_unlock(&priv->lock);
> +
> + return 0;
> +}
> +
> +static struct thermal_zone_of_device_ops zx2967_of_thermal_ops = {
> + .get_temp = zx2967_thermal_get_temp,
> +};
> +
> +static int zx2967_thermal_probe(struct platform_device *pdev)
> +{
> + struct zx2967_thermal_priv *priv;
> + struct resource *res;
> + u32 buf[2];
> + int ret, i;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + priv->regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(priv->regs))
> + return PTR_ERR(priv->regs);
> +
> + ret = of_property_read_u32_array(pdev->dev.of_node,
> + "coefficients", buf, 2);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to read coefficients\n");
> + return ret;
> + }
> + priv->slope = (s32)buf[0];
> + priv->offset = (s32)buf[1];
Are you sure you don't want to check the values of ->slope and ->offset? I
certainly wouldn't trust the DT...
> +
> + priv->clk_gate = devm_clk_get(&pdev->dev, "gate");
> + if (IS_ERR(priv->clk_gate)) {
> + ret = PTR_ERR(priv->clk_gate);
> + dev_err(&pdev->dev, "failed to get clock gate: %d\n", ret);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(priv->clk_gate);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> + ret);
> + return ret;
> + }
> +
> + priv->pclk = devm_clk_get(&pdev->dev, "pclk");
> + if (IS_ERR(priv->pclk)) {
> + ret = PTR_ERR(priv->pclk);
> + clk_disable_unprepare(priv->clk_gate);
An error path is already defined below - add a 'goto' statement that jumps to
it. That way it consolidates the exit point for the function and avoid code
duplication.
> + dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(priv->pclk);
> + if (ret) {
> + clk_disable_unprepare(priv->clk_gate);
Same comment a above.
> + dev_err(&pdev->dev, "failed to enable converter clock: %d\n",
> + ret);
> + return ret;
> + }
> +
> + mutex_init(&priv->lock);
> + for (i = 0; i < NUM_SENSORS; i++) {
> + struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> + sensor->priv = priv;
> + sensor->id = i;
> + sensor->tzd = thermal_zone_of_sensor_register(&pdev->dev,
> + i, sensor, &zx2967_of_thermal_ops);
> + if (IS_ERR(sensor->tzd)) {
> + ret = PTR_ERR(sensor->tzd);
> + dev_err(&pdev->dev, "failed to register sensor %d: %d\n",
> + i, ret);
> + goto remove_ts;
> + }
> + }
> + priv->dev = &pdev->dev;
> + platform_set_drvdata(pdev, priv);
> +
> + return 0;
> +
> +remove_ts:
> + clk_disable_unprepare(priv->clk_gate);
> + clk_disable_unprepare(priv->pclk);
> + for (i--; i >= 0; i--)
> + thermal_zone_of_sensor_unregister(&pdev->dev,
> + priv->sensors[i].tzd);
> +
> + return ret;
> +}
> +
> +static int zx2967_thermal_exit(struct platform_device *pdev)
> +{
> + struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
> + int i;
> +
> + for (i = 0; i < NUM_SENSORS; i++) {
> + struct zx2967_thermal_sensor *sensor = &priv->sensors[i];
> +
> + thermal_zone_of_sensor_unregister(&pdev->dev, sensor->tzd);
> + }
> + clk_disable_unprepare(priv->pclk);
> + clk_disable_unprepare(priv->clk_gate);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id zx2967_thermal_id_table[] = {
> + { .compatible = "zte,zx296718-thermal" },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
> +
> +static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
> + zx2967_thermal_suspend, zx2967_thermal_resume);
> +
> +static struct platform_driver zx2967_thermal_driver = {
> + .probe = zx2967_thermal_probe,
> + .remove = zx2967_thermal_exit,
> + .driver = {
> + .name = "zx2967_thermal",
> + .of_match_table = zx2967_thermal_id_table,
> + .pm = &zx2967_thermal_pm_ops,
> + },
> +};
> +module_platform_driver(zx2967_thermal_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.7.4
>
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