diff options
| -rw-r--r-- | drivers/acpi/acpi_lpss.c | 157 |
1 files changed, 150 insertions, 7 deletions
diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c index 69e29f409d4c..a01d4d1343dd 100644 --- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -19,6 +19,7 @@ #include <linux/platform_device.h> #include <linux/platform_data/clk-lpss.h> #include <linux/pm_runtime.h> +#include <linux/delay.h> #include "internal.h" @@ -43,6 +44,8 @@ ACPI_MODULE_NAME("acpi_lpss"); #define LPSS_TX_INT 0x20 #define LPSS_TX_INT_MASK BIT(1) +#define LPSS_PRV_REG_COUNT 9 + struct lpss_shared_clock { const char *name; unsigned long rate; @@ -58,6 +61,7 @@ struct lpss_device_desc { unsigned int prv_offset; size_t prv_size_override; bool clk_gate; + bool save_ctx; struct lpss_shared_clock *shared_clock; void (*setup)(struct lpss_private_data *pdata); }; @@ -72,6 +76,7 @@ struct lpss_private_data { resource_size_t mmio_size; struct clk *clk; const struct lpss_device_desc *dev_desc; + u32 prv_reg_ctx[LPSS_PRV_REG_COUNT]; }; static void lpss_uart_setup(struct lpss_private_data *pdata) @@ -116,6 +121,7 @@ static struct lpss_shared_clock pwm_clock = { static struct lpss_device_desc byt_pwm_dev_desc = { .clk_required = true, + .save_ctx = true, .shared_clock = &pwm_clock, }; @@ -128,6 +134,7 @@ static struct lpss_device_desc byt_uart_dev_desc = { .clk_required = true, .prv_offset = 0x800, .clk_gate = true, + .save_ctx = true, .shared_clock = &uart_clock, .setup = lpss_uart_setup, }; @@ -141,6 +148,7 @@ static struct lpss_device_desc byt_spi_dev_desc = { .clk_required = true, .prv_offset = 0x400, .clk_gate = true, + .save_ctx = true, .shared_clock = &spi_clock, }; @@ -156,6 +164,7 @@ static struct lpss_shared_clock i2c_clock = { static struct lpss_device_desc byt_i2c_dev_desc = { .clk_required = true, .prv_offset = 0x800, + .save_ctx = true, .shared_clock = &i2c_clock, }; @@ -449,6 +458,126 @@ static void acpi_lpss_set_ltr(struct device *dev, s32 val) } } +#ifdef CONFIG_PM +/** + * acpi_lpss_save_ctx() - Save the private registers of LPSS device + * @dev: LPSS device + * + * Most LPSS devices have private registers which may loose their context when + * the device is powered down. acpi_lpss_save_ctx() saves those registers into + * prv_reg_ctx array. + */ +static void acpi_lpss_save_ctx(struct device *dev) +{ + struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev)); + unsigned int i; + + for (i = 0; i < LPSS_PRV_REG_COUNT; i++) { + unsigned long offset = i * sizeof(u32); + + pdata->prv_reg_ctx[i] = __lpss_reg_read(pdata, offset); + dev_dbg(dev, "saving 0x%08x from LPSS reg at offset 0x%02lx\n", + pdata->prv_reg_ctx[i], offset); + } +} + +/** + * acpi_lpss_restore_ctx() - Restore the private registers of LPSS device + * @dev: LPSS device + * + * Restores the registers that were previously stored with acpi_lpss_save_ctx(). + */ +static void acpi_lpss_restore_ctx(struct device *dev) +{ + struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev)); + unsigned int i; + + /* + * The following delay is needed or the subsequent write operations may + * fail. The LPSS devices are actually PCI devices and the PCI spec + * expects 10ms delay before the device can be accessed after D3 to D0 + * transition. + */ + msleep(10); + + for (i = 0; i < LPSS_PRV_REG_COUNT; i++) { + unsigned long offset = i * sizeof(u32); + + __lpss_reg_write(pdata->prv_reg_ctx[i], pdata, offset); + dev_dbg(dev, "restoring 0x%08x to LPSS reg at offset 0x%02lx\n", + pdata->prv_reg_ctx[i], offset); + } +} + +#ifdef CONFIG_PM_SLEEP +static int acpi_lpss_suspend_late(struct device *dev) +{ + int ret = pm_generic_suspend_late(dev); + + if (ret) + return ret; + + acpi_lpss_save_ctx(dev); + return acpi_dev_suspend_late(dev); +} + +static int acpi_lpss_restore_early(struct device *dev) +{ + int ret = acpi_dev_resume_early(dev); + + if (ret) + return ret; + + acpi_lpss_restore_ctx(dev); + return pm_generic_resume_early(dev); +} +#endif /* CONFIG_PM_SLEEP */ + +#ifdef CONFIG_PM_RUNTIME +static int acpi_lpss_runtime_suspend(struct device *dev) +{ + int ret = pm_generic_runtime_suspend(dev); + + if (ret) + return ret; + + acpi_lpss_save_ctx(dev); + return acpi_dev_runtime_suspend(dev); +} + +static int acpi_lpss_runtime_resume(struct device *dev) +{ + int ret = acpi_dev_runtime_resume(dev); + + if (ret) + return ret; + + acpi_lpss_restore_ctx(dev); + return pm_generic_runtime_resume(dev); +} +#endif /* CONFIG_PM_RUNTIME */ +#endif /* CONFIG_PM */ + +static struct dev_pm_domain acpi_lpss_pm_domain = { + .ops = { +#ifdef CONFIG_PM_SLEEP + .suspend_late = acpi_lpss_suspend_late, + .restore_early = acpi_lpss_restore_early, + .prepare = acpi_subsys_prepare, + .complete = acpi_subsys_complete, + .suspend = acpi_subsys_suspend, + .resume_early = acpi_subsys_resume_early, + .freeze = acpi_subsys_freeze, + .poweroff = acpi_subsys_suspend, + .poweroff_late = acpi_subsys_suspend_late, +#endif +#ifdef CONFIG_PM_RUNTIME + .runtime_suspend = acpi_lpss_runtime_suspend, + .runtime_resume = acpi_lpss_runtime_resume, +#endif + }, +}; + static int acpi_lpss_platform_notify(struct notifier_block *nb, unsigned long action, void *data) { @@ -456,7 +585,6 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb, struct lpss_private_data *pdata; struct acpi_device *adev; const struct acpi_device_id *id; - int ret = 0; id = acpi_match_device(acpi_lpss_device_ids, &pdev->dev); if (!id || !id->driver_data) @@ -466,7 +594,7 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb, return 0; pdata = acpi_driver_data(adev); - if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required) + if (!pdata || !pdata->mmio_base) return 0; if (pdata->mmio_size < pdata->dev_desc->prv_offset + LPSS_LTR_SIZE) { @@ -474,12 +602,27 @@ static int acpi_lpss_platform_notify(struct notifier_block *nb, return 0; } - if (action == BUS_NOTIFY_ADD_DEVICE) - ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group); - else if (action == BUS_NOTIFY_DEL_DEVICE) - sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group); + switch (action) { + case BUS_NOTIFY_BOUND_DRIVER: + if (pdata->dev_desc->save_ctx) + pdev->dev.pm_domain = &acpi_lpss_pm_domain; + break; + case BUS_NOTIFY_UNBOUND_DRIVER: + if (pdata->dev_desc->save_ctx) + pdev->dev.pm_domain = NULL; + break; + case BUS_NOTIFY_ADD_DEVICE: + if (pdata->dev_desc->ltr_required) + return sysfs_create_group(&pdev->dev.kobj, + &lpss_attr_group); + case BUS_NOTIFY_DEL_DEVICE: + if (pdata->dev_desc->ltr_required) + sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group); + default: + break; + } - return ret; + return 0; } static struct notifier_block acpi_lpss_nb = { |