diff options
Diffstat (limited to 'drivers/hwmon/sfctemp.c')
| -rw-r--r-- | drivers/hwmon/sfctemp.c | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/drivers/hwmon/sfctemp.c b/drivers/hwmon/sfctemp.c new file mode 100644 index 000000000000..d7af616b8d09 --- /dev/null +++ b/drivers/hwmon/sfctemp.c @@ -0,0 +1,349 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk> + * Copyright (C) 2021 Samin Guo <samin.guo@starfivetech.com> + */ +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/hwmon.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/reset.h> + +/* + * TempSensor reset. The RSTN can be de-asserted once the analog core has + * powered up. Trst(min 100ns) + * 0:reset 1:de-assert + */ +#define SFCTEMP_RSTN BIT(0) + +/* + * TempSensor analog core power down. The analog core will be powered up + * Tpu(min 50us) after PD is de-asserted. RSTN should be held low until the + * analog core is powered up. + * 0:power up 1:power down + */ +#define SFCTEMP_PD BIT(1) + +/* + * TempSensor start conversion enable. + * 0:disable 1:enable + */ +#define SFCTEMP_RUN BIT(2) + +/* + * TempSensor conversion value output. + * Temp(C)=DOUT*Y/4094 - K + */ +#define SFCTEMP_DOUT_POS 16 +#define SFCTEMP_DOUT_MSK GENMASK(27, 16) + +/* DOUT to Celcius conversion constants */ +#define SFCTEMP_Y1000 237500L +#define SFCTEMP_Z 4094L +#define SFCTEMP_K1000 81100L + +struct sfctemp { + /* serialize access to hardware register and enabled below */ + struct mutex lock; + struct completion conversion_done; + void __iomem *regs; + struct clk *clk_sense; + struct clk *clk_bus; + struct reset_control *rst_sense; + struct reset_control *rst_bus; + bool enabled; +}; + +static irqreturn_t sfctemp_isr(int irq, void *data) +{ + struct sfctemp *sfctemp = data; + + complete(&sfctemp->conversion_done); + return IRQ_HANDLED; +} + +static void sfctemp_power_up(struct sfctemp *sfctemp) +{ + /* make sure we're powered down first */ + writel(SFCTEMP_PD, sfctemp->regs); + udelay(1); + + writel(0, sfctemp->regs); + /* wait t_pu(50us) + t_rst(100ns) */ + usleep_range(60, 200); + + /* de-assert reset */ + writel(SFCTEMP_RSTN, sfctemp->regs); + udelay(1); /* wait t_su(500ps) */ +} + +static void sfctemp_power_down(struct sfctemp *sfctemp) +{ + writel(SFCTEMP_PD, sfctemp->regs); +} + +static void sfctemp_run_single(struct sfctemp *sfctemp) +{ + writel(SFCTEMP_RSTN | SFCTEMP_RUN, sfctemp->regs); + udelay(1); + writel(SFCTEMP_RSTN, sfctemp->regs); +} + +static int sfctemp_enable(struct sfctemp *sfctemp) +{ + int ret = 0; + + mutex_lock(&sfctemp->lock); + if (sfctemp->enabled) + goto done; + + ret = clk_prepare_enable(sfctemp->clk_bus); + if (ret) + goto err; + ret = reset_control_deassert(sfctemp->rst_bus); + if (ret) + goto err_disable_bus; + + ret = clk_prepare_enable(sfctemp->clk_sense); + if (ret) + goto err_assert_bus; + ret = reset_control_deassert(sfctemp->rst_sense); + if (ret) + goto err_disable_sense; + + sfctemp_power_up(sfctemp); + sfctemp->enabled = true; +done: + mutex_unlock(&sfctemp->lock); + return ret; + +err_disable_sense: + clk_disable_unprepare(sfctemp->clk_sense); +err_assert_bus: + reset_control_assert(sfctemp->rst_bus); +err_disable_bus: + clk_disable_unprepare(sfctemp->clk_bus); +err: + mutex_unlock(&sfctemp->lock); + return ret; +} + +static int sfctemp_disable(struct sfctemp *sfctemp) +{ + mutex_lock(&sfctemp->lock); + if (!sfctemp->enabled) + goto done; + + sfctemp_power_down(sfctemp); + reset_control_assert(sfctemp->rst_sense); + clk_disable_unprepare(sfctemp->clk_sense); + reset_control_assert(sfctemp->rst_bus); + clk_disable_unprepare(sfctemp->clk_bus); + sfctemp->enabled = false; +done: + mutex_unlock(&sfctemp->lock); + return 0; +} + +static void sfctemp_disable_action(void *data) +{ + sfctemp_disable(data); +} + +static int sfctemp_convert(struct sfctemp *sfctemp, long *val) +{ + int ret; + + mutex_lock(&sfctemp->lock); + if (!sfctemp->enabled) { + ret = -ENODATA; + goto out; + } + + sfctemp_run_single(sfctemp); + + ret = wait_for_completion_interruptible_timeout(&sfctemp->conversion_done, + msecs_to_jiffies(10)); + if (ret <= 0) { + if (ret == 0) + ret = -ETIMEDOUT; + goto out; + } + + /* calculate temperature in milli Celcius */ + *val = (long)((readl(sfctemp->regs) & SFCTEMP_DOUT_MSK) >> SFCTEMP_DOUT_POS) + * SFCTEMP_Y1000 / SFCTEMP_Z - SFCTEMP_K1000; + + ret = 0; +out: + mutex_unlock(&sfctemp->lock); + return ret; +} + +static umode_t sfctemp_is_visible(const void *data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_enable: + return 0644; + case hwmon_temp_input: + return 0444; + } + return 0; + default: + return 0; + } +} + +static int sfctemp_read(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long *val) +{ + struct sfctemp *sfctemp = dev_get_drvdata(dev); + + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_enable: + *val = sfctemp->enabled; + return 0; + case hwmon_temp_input: + return sfctemp_convert(sfctemp, val); + } + return -EINVAL; + default: + return -EINVAL; + } +} + +static int sfctemp_write(struct device *dev, enum hwmon_sensor_types type, + u32 attr, int channel, long val) +{ + struct sfctemp *sfctemp = dev_get_drvdata(dev); + + switch (type) { + case hwmon_temp: + switch (attr) { + case hwmon_temp_enable: + if (val == 0) + return sfctemp_disable(sfctemp); + if (val == 1) + return sfctemp_enable(sfctemp); + break; + } + return -EINVAL; + default: + return -EINVAL; + } +} + +static const struct hwmon_channel_info *sfctemp_info[] = { + HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), + HWMON_CHANNEL_INFO(temp, HWMON_T_ENABLE | HWMON_T_INPUT), + NULL +}; + +static const struct hwmon_ops sfctemp_hwmon_ops = { + .is_visible = sfctemp_is_visible, + .read = sfctemp_read, + .write = sfctemp_write, +}; + +static const struct hwmon_chip_info sfctemp_chip_info = { + .ops = &sfctemp_hwmon_ops, + .info = sfctemp_info, +}; + +static int sfctemp_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device *hwmon_dev; + struct sfctemp *sfctemp; + int ret; + + sfctemp = devm_kzalloc(dev, sizeof(*sfctemp), GFP_KERNEL); + if (!sfctemp) + return -ENOMEM; + + dev_set_drvdata(dev, sfctemp); + mutex_init(&sfctemp->lock); + init_completion(&sfctemp->conversion_done); + + sfctemp->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(sfctemp->regs)) + return PTR_ERR(sfctemp->regs); + + sfctemp->clk_sense = devm_clk_get(dev, "sense"); + if (IS_ERR(sfctemp->clk_sense)) + return dev_err_probe(dev, PTR_ERR(sfctemp->clk_sense), + "error getting sense clock\n"); + + sfctemp->clk_bus = devm_clk_get(dev, "bus"); + if (IS_ERR(sfctemp->clk_bus)) + return dev_err_probe(dev, PTR_ERR(sfctemp->clk_bus), + "error getting bus clock\n"); + + sfctemp->rst_sense = devm_reset_control_get_exclusive(dev, "sense"); + if (IS_ERR(sfctemp->rst_sense)) + return dev_err_probe(dev, PTR_ERR(sfctemp->rst_sense), + "error getting sense reset\n"); + + sfctemp->rst_bus = devm_reset_control_get_exclusive(dev, "bus"); + if (IS_ERR(sfctemp->rst_bus)) + return dev_err_probe(dev, PTR_ERR(sfctemp->rst_bus), + "error getting busreset\n"); + + ret = reset_control_assert(sfctemp->rst_sense); + if (ret) + return dev_err_probe(dev, ret, "error asserting sense reset\n"); + + ret = reset_control_assert(sfctemp->rst_bus); + if (ret) + return dev_err_probe(dev, ret, "error asserting bus reset\n"); + + ret = platform_get_irq(pdev, 0); + if (ret < 0) + return ret; + + ret = devm_request_irq(dev, ret, sfctemp_isr, 0, pdev->name, sfctemp); + if (ret) + return dev_err_probe(dev, ret, "error requesting irq\n"); + + ret = devm_add_action(dev, sfctemp_disable_action, sfctemp); + if (ret) + return ret; + + ret = sfctemp_enable(sfctemp); + if (ret) + return dev_err_probe(dev, ret, "error enabling temperature sensor: %d\n", ret); + + hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev->name, sfctemp, + &sfctemp_chip_info, NULL); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct of_device_id sfctemp_of_match[] = { + { .compatible = "starfive,jh7100-temp" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, sfctemp_of_match); + +static struct platform_driver sfctemp_driver = { + .probe = sfctemp_probe, + .driver = { + .name = "sfctemp", + .of_match_table = sfctemp_of_match, + }, +}; +module_platform_driver(sfctemp_driver); + +MODULE_AUTHOR("Emil Renner Berthing"); +MODULE_DESCRIPTION("StarFive JH7100 temperature sensor driver"); +MODULE_LICENSE("GPL"); |