This patch adds the support for allwinner thermal sensor, within
allwinner SoC. It will register sensors for thermal framework
and use device tree to bind cooling device.

Signed-off-by: Yangtao Li <tiny.win...@gmail.com>
---
 MAINTAINERS                     |   7 +
 drivers/thermal/Kconfig         |  14 +
 drivers/thermal/Makefile        |   1 +
 drivers/thermal/sun8i_thermal.c | 437 ++++++++++++++++++++++++++++++++
 4 files changed, 459 insertions(+)
 create mode 100644 drivers/thermal/sun8i_thermal.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 2336dd26ece4..d312f9eecf0d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -674,6 +674,13 @@ L: linux-cry...@vger.kernel.org
 S:     Maintained
 F:     drivers/crypto/sunxi-ss/
 
+ALLWINNER THERMAL DRIVER
+M:     Yangtao Li <tiny.win...@gmail.com>
+L:     linux...@vger.kernel.org
+S:     Maintained
+F:     Documentation/devicetree/bindings/thermal/sun8i-thermal.yaml
+F:     drivers/thermal/sun8i_thermal.c
+
 ALLWINNER VPU DRIVER
 M:     Maxime Ripard <maxime.rip...@bootlin.com>
 M:     Paul Kocialkowski <paul.kocialkow...@bootlin.com>
diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 9966364a6deb..e5465053d66f 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -262,6 +262,20 @@ config SPEAR_THERMAL
          Enable this to plug the SPEAr thermal sensor driver into the Linux
          thermal framework.
 
+config SUN8I_THERMAL
+       tristate "Allwinner sun8i thermal driver"
+       depends on ARCH_SUNXI || COMPILE_TEST
+       depends on HAS_IOMEM
+       depends on NVMEM_SUNXI_SID
+       depends on OF
+       depends on RESET_CONTROLLER
+       help
+         Support for the sun8i thermal sensor driver into the Linux thermal
+         framework.
+
+         To compile this driver as a module, choose M here: the
+         module will be called sun8i-thermal.
+
 config ROCKCHIP_THERMAL
        tristate "Rockchip thermal driver"
        depends on ARCH_ROCKCHIP || COMPILE_TEST
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 74a37c7f847a..fa6f8b206281 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -31,6 +31,7 @@ thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o
 obj-y                          += broadcom/
 obj-$(CONFIG_THERMAL_MMIO)             += thermal_mmio.o
 obj-$(CONFIG_SPEAR_THERMAL)    += spear_thermal.o
+obj-$(CONFIG_SUN8I_THERMAL)     += sun8i_thermal.o
 obj-$(CONFIG_ROCKCHIP_THERMAL) += rockchip_thermal.o
 obj-$(CONFIG_RCAR_THERMAL)     += rcar_thermal.o
 obj-$(CONFIG_RCAR_GEN3_THERMAL)        += rcar_gen3_thermal.o
diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
new file mode 100644
index 000000000000..a9cc2197f4cb
--- /dev/null
+++ b/drivers/thermal/sun8i_thermal.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Thermal sensor driver for Allwinner SOC
+ * Copyright (C) 2019 Yangtao Li
+ *
+ * Based on the work of Icenowy Zheng <icen...@aosc.io>
+ * Based on the work of Ondrej Jirman <meg...@megous.com>
+ * Based on the work of Josef Gajdusek <a...@atx.name>
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#define MAX_SENSOR_NUM 4
+
+#define FT_TEMP_MASK                           GENMASK(11, 0)
+#define TEMP_CALIB_MASK                                GENMASK(11, 0)
+#define TEMP_TO_REG                            672
+#define CALIBRATE_DEFAULT                      0x800
+
+#define SUN50I_THS_CTRL0                       0x00
+#define SUN50I_H6_THS_ENABLE                   0x04
+#define SUN50I_H6_THS_PC                       0x08
+#define SUN50I_H6_THS_DIC                      0x10
+#define SUN50I_H6_THS_DIS                      0x20
+#define SUN50I_H6_THS_MFC                      0x30
+#define SUN50I_H6_THS_TEMP_CALIB               0xa0
+#define SUN50I_H6_THS_TEMP_DATA                        0xc0
+
+#define SUN50I_THS_CTRL0_T_ACQ(x)              ((GENMASK(15, 0) & (x)) << 16)
+#define SUN50I_THS_FILTER_EN                   BIT(2)
+#define SUN50I_THS_FILTER_TYPE(x)              (GENMASK(1, 0) & (x))
+#define SUN50I_H6_THS_PC_TEMP_PERIOD(x)                ((GENMASK(19, 0) & (x)) 
<< 12)
+#define SUN50I_H6_THS_DATA_IRQ_STS(x)          BIT(x)
+
+/* millidegree celsius */
+#define SUN50I_H6_FT_DEVIATION                 7000
+
+struct ths_device;
+
+struct tsensor {
+       struct ths_device               *tmdev;
+       struct thermal_zone_device      *tzd;
+       int                             id;
+       wait_queue_head_t               wait_queue;
+};
+
+struct ths_thermal_chip {
+       int             sensor_num;
+       int             offset;
+       int             scale;
+       int             ft_deviation;
+       int             temp_calib_base;
+       int             temp_data_base;
+       int             (*calibrate)(struct ths_device *tmdev);
+       int             (*init)(struct ths_device *tmdev);
+       irqreturn_t     (*irq_thread)(int irq, void *data);
+};
+
+struct ths_device {
+       const struct ths_thermal_chip           *chip;
+       struct device                           *dev;
+       struct regmap                           *regmap;
+       struct reset_control                    *reset;
+       struct clk                              *bus_clk;
+       struct tsensor                          sensor[MAX_SENSOR_NUM];
+       int                                     data_ready;
+};
+
+/* Temp Unit: millidegree Celsius */
+static int sun8i_ths_reg2temp(struct ths_device *tmdev,
+                             int reg)
+{
+       return (reg + tmdev->chip->offset) * tmdev->chip->scale;
+}
+
+static int sun8i_ths_get_temp(void *data, int *temp)
+{
+       struct tsensor *s = data;
+       struct ths_device *tmdev = s->tmdev;
+       int val;
+
+       wait_event(s->wait_queue, tmdev->data_ready & BIT(s->id));
+       tmdev->data_ready &= ~BIT(s->id);
+
+       regmap_read(tmdev->regmap, tmdev->chip->temp_data_base +
+                   0x4 * s->id, &val);
+
+       *temp = sun8i_ths_reg2temp(tmdev, val);
+       /*
+        * XX - According to the original sdk, there are some platforms(rarely)
+        * that add a fixed offset value after calculating the temperature
+        * value. We can't simply put it on the formula for calculating the
+        * temperature above, because the formula for calculating the
+        * temperature above is also used when the sensor is calibrated. If
+        * do this, the correct calibration formula is hard to know.
+        */
+       if (tmdev->chip->ft_deviation)
+               *temp += tmdev->chip->ft_deviation;
+
+       return 0;
+}
+
+static const struct thermal_zone_of_device_ops ths_ops = {
+       .get_temp = sun8i_ths_get_temp,
+};
+
+static const struct regmap_config config = {
+       .reg_bits = 32,
+       .val_bits = 32,
+       .reg_stride = 4,
+       .fast_io = true,
+};
+
+static irqreturn_t sun50i_h6_irq_thread(int irq, void *data)
+{
+       wait_queue_head_t *data_wait;
+       struct ths_device *tmdev = data;
+       int i, state;
+
+       regmap_read(tmdev->regmap, SUN50I_H6_THS_DIS, &state);
+
+       for (i = 0; i < tmdev->chip->sensor_num; i++) {
+               data_wait = &tmdev->sensor[i].wait_queue;
+
+               if (state & SUN50I_H6_THS_DATA_IRQ_STS(i)) {
+                       /* clear data irq pending */
+                       regmap_write(tmdev->regmap, SUN50I_H6_THS_DIS,
+                                    SUN50I_H6_THS_DATA_IRQ_STS(i));
+
+                       tmdev->data_ready |= BIT(i);
+                       wake_up(data_wait);
+               }
+       }
+
+       return IRQ_HANDLED;
+}
+
+static int sun8i_ths_resource_init(struct ths_device *tmdev)
+{
+       struct device *dev = tmdev->dev;
+       struct platform_device *pdev = to_platform_device(dev);
+       struct resource *mem;
+       void __iomem *base;
+       int ret, irq;
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(dev, mem);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+
+       tmdev->regmap = devm_regmap_init_mmio(dev, base, &config);
+       if (IS_ERR(tmdev->regmap))
+               return PTR_ERR(tmdev->regmap);
+
+       tmdev->reset = devm_reset_control_get(dev, 0);
+       if (IS_ERR(tmdev->reset))
+               return PTR_ERR(tmdev->reset);
+
+       tmdev->bus_clk = devm_clk_get(&pdev->dev, "bus");
+       if (IS_ERR(tmdev->bus_clk))
+               return PTR_ERR(tmdev->bus_clk);
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0)
+               return irq;
+
+       ret = devm_request_threaded_irq(dev, irq, NULL,
+                                       tmdev->chip->irq_thread,
+                                       IRQF_ONESHOT, "ths", tmdev);
+       if (ret)
+               return ret;
+
+       ret = reset_control_deassert(tmdev->reset);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare_enable(tmdev->bus_clk);
+       if (ret)
+               goto assert_reset;
+
+       ret = tmdev->chip->calibrate(tmdev);
+       if (ret)
+               goto bus_disable;
+
+       return 0;
+
+bus_disable:
+       clk_disable_unprepare(tmdev->bus_clk);
+assert_reset:
+       reset_control_assert(tmdev->reset);
+
+       return ret;
+}
+
+static int sun50i_ths_calibrate(struct ths_device *tmdev)
+{
+       struct nvmem_cell *calcell;
+       struct device *dev = tmdev->dev;
+       u16 *caldata;
+       size_t callen;
+       int ft_temp;
+       int i, ret = 0;
+
+       calcell = devm_nvmem_cell_get(dev, "calib");
+       if (IS_ERR(calcell)) {
+               if (PTR_ERR(calcell) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+               /*
+                * Even if the external calibration data stored in sid is
+                * not accessible, the THS hardware can still work, although
+                * the data won't be so accurate.
+                *
+                * The default value of calibration register is 0x800 for
+                * every sensor, and the calibration value is usually 0x7xx
+                * or 0x8xx, so they won't be away from the default value
+                * for a lot.
+                *
+                * So here we do not return error if the calibartion data is
+                * not available, except the probe needs deferring.
+                */
+               goto out;
+       }
+
+       caldata = nvmem_cell_read(calcell, &callen);
+       if (IS_ERR(caldata)) {
+               ret = PTR_ERR(caldata);
+               goto out;
+       }
+
+       if (!caldata[0] || callen < 2 + 2 * tmdev->chip->sensor_num) {
+               ret = -EINVAL;
+               goto out_free;
+       }
+
+       /*
+        * efuse layout:
+        *
+        *      0   11  16       32
+        *      +-------+-------+-------+
+        *      |temp|  |sensor0|sensor1|
+        *      +-------+-------+-------+
+        *
+        * The calibration data on the H6 is the ambient temperature and
+        * sensor values that are filled during the factory test stage.
+        *
+        * The unit of stored FT temperature is 0.1 degreee celusis.
+        * Through the stored ambient temperature and the data read
+        * by the sensor, after a certain calculation, the calibration
+        * value to be compensated can be obtained.
+        */
+       ft_temp = caldata[0] & FT_TEMP_MASK;
+
+       for (i = 0; i < tmdev->chip->sensor_num; i++) {
+               int reg = (int)caldata[i + 1];
+               int sensor_temp = sun8i_ths_reg2temp(tmdev, reg);
+               int delta, cdata, calib_offest;
+
+               /*
+                * To calculate the calibration value:
+                *
+                * X(in Celsius) = Ts - ft_temp
+                * delta = X * 10000 / TEMP_TO_REG
+                * cdata = CALIBRATE_DEFAULT - delta
+                *
+                * cdata: calibration value
+                */
+               delta = (sensor_temp - ft_temp * 100) * 10 / TEMP_TO_REG;
+               cdata = CALIBRATE_DEFAULT - delta;
+               if (cdata & ~TEMP_CALIB_MASK) {
+                       /*
+                        * Calibration value more than 12-bit, but calibration
+                        * register is 12-bit. In this case, ths hardware can
+                        * still work without calibration, although the data
+                        * won't be so accurate.
+                        */
+                       dev_warn(dev, "sensor%d is not calibrated.\n", i);
+
+                       continue;
+               }
+
+               calib_offest = tmdev->chip->temp_calib_base + (i / 2) * 0x4;
+
+               if (i % 2) {
+                       int val;
+
+                       regmap_read(tmdev->regmap, calib_offest, &val);
+                       val = (val & TEMP_CALIB_MASK) | (cdata << 16);
+                       regmap_write(tmdev->regmap, calib_offest, val);
+               } else {
+                       regmap_write(tmdev->regmap, calib_offest, cdata);
+               }
+       }
+
+out_free:
+       kfree(caldata);
+out:
+       return ret;
+}
+
+static int sun8i_ths_register(struct ths_device *tmdev)
+{
+       struct thermal_zone_device *tzd;
+       int i;
+
+       for (i = 0; i < tmdev->chip->sensor_num; i++) {
+               tmdev->sensor[i].tmdev = tmdev;
+               tmdev->sensor[i].id = i;
+               tmdev->sensor[i].tzd =
+                       devm_thermal_zone_of_sensor_register(tmdev->dev,
+                                                            i,
+                                                            &tmdev->sensor[i],
+                                                            &ths_ops);
+               if (IS_ERR(tmdev->sensor[i].tzd))
+                       return PTR_ERR(tzd);
+       }
+
+       return 0;
+}
+
+static int sun8i_ths_probe(struct platform_device *pdev)
+{
+       struct ths_device *tmdev;
+       struct device *dev = &pdev->dev;
+       int i, ret;
+
+       tmdev = devm_kzalloc(dev, sizeof(*tmdev), GFP_KERNEL);
+       if (!tmdev)
+               return -ENOMEM;
+
+       tmdev->dev = dev;
+       tmdev->chip = of_device_get_match_data(&pdev->dev);
+       if (!tmdev->chip)
+               return -EINVAL;
+
+       /*
+        * Initialize wait_queue in advance, to avoid calling wake_up
+        * before ths is registered in isr.
+        */
+       for (i = 0; i < tmdev->chip->sensor_num; i++)
+               init_waitqueue_head(&tmdev->sensor[i].wait_queue);
+
+       platform_set_drvdata(pdev, tmdev);
+
+       ret = sun8i_ths_resource_init(tmdev);
+       if (ret)
+               return ret;
+
+       ret = tmdev->chip->init(tmdev);
+       if (ret)
+               return ret;
+
+       ret = sun8i_ths_register(tmdev);
+       if (ret)
+               return ret;
+
+       return ret;
+}
+
+static int sun8i_ths_remove(struct platform_device *pdev)
+{
+       struct ths_device *tmdev = platform_get_drvdata(pdev);
+
+       clk_disable_unprepare(tmdev->bus_clk);
+       reset_control_assert(tmdev->reset);
+
+       return 0;
+}
+
+static int sun50i_thermal_init(struct ths_device *tmdev)
+{
+       int val;
+
+       /*
+        * clkin = 24MHz
+        * T acquire = clkin / (x + 1)
+        *           = 20us
+        */
+       regmap_write(tmdev->regmap, SUN50I_THS_CTRL0,
+                    SUN50I_THS_CTRL0_T_ACQ(479));
+       /* average over 4 samples */
+       regmap_write(tmdev->regmap, SUN50I_H6_THS_MFC,
+                    SUN50I_THS_FILTER_EN |
+                    SUN50I_THS_FILTER_TYPE(1));
+       /* period = (x + 1) * 4096 / clkin; ~10ms */
+       regmap_write(tmdev->regmap, SUN50I_H6_THS_PC,
+                    SUN50I_H6_THS_PC_TEMP_PERIOD(58));
+       /* enable sensor */
+       val = GENMASK(tmdev->chip->sensor_num - 1, 0);
+       regmap_write(tmdev->regmap, SUN50I_H6_THS_ENABLE, val);
+       /* thermal data interrupt enable */
+       val = GENMASK(tmdev->chip->sensor_num - 1, 0);
+       regmap_write(tmdev->regmap, SUN50I_H6_THS_DIC, val);
+
+       return 0;
+}
+
+static const struct ths_thermal_chip sun50i_h6_ths = {
+       .sensor_num = 2,
+       .offset = -2794,
+       .scale = -67,
+       .ft_deviation = SUN50I_H6_FT_DEVIATION,
+       .temp_calib_base = SUN50I_H6_THS_TEMP_CALIB,
+       .temp_data_base = SUN50I_H6_THS_TEMP_DATA,
+       .calibrate = sun50i_ths_calibrate,
+       .init = sun50i_thermal_init,
+       .irq_thread = sun50i_h6_irq_thread,
+};
+
+static const struct of_device_id of_ths_match[] = {
+       { .compatible = "allwinner,sun50i-h6-ths", .data = &sun50i_h6_ths },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, of_ths_match);
+
+static struct platform_driver ths_driver = {
+       .probe = sun8i_ths_probe,
+       .remove = sun8i_ths_remove,
+       .driver = {
+               .name = "sun8i-thermal",
+               .of_match_table = of_ths_match,
+       },
+};
+module_platform_driver(ths_driver);
+
+MODULE_DESCRIPTION("Thermal sensor driver for Allwinner SOC");
+MODULE_LICENSE("GPL v2");
-- 
2.17.0

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