[PATCH v17 2/6] spi: pxa2xx: introduce clock enable and disable helper functions
flat view
COOLING14d
From: Shih-Yuan Lee <hidden>
Date: 2026-09-30 16:07:08
Also in:
linux-spi, lkml
Subsystem:
intel lpss (low power subsystem) drivers, pxa2xx/pxa3xx support, spi subsystem, the rest · Maintainers:
Daniel Mack, Haojian Zhuang, Robert Jarzmik, Mark Brown, Linus Torvalds
The driver enables and disables the SOC clock during probe, teardown, and power management callbacks. Directly calling clk_disable_unprepare() when the clock is already disabled—such as when removing a device that is runtime-suspended—causes an unbalanced clock disable warning from the Common Clock Framework. Introduce pxa2xx_spi_clk_enable() and pxa2xx_spi_clk_disable() helper functions that track the clock state with a 'clk_enabled' boolean flag protected by a 'clk_lock' mutex in struct driver_data. These helpers make clock toggling idempotent: repeated enable or disable invocations are safe no-ops serialized by clk_lock. Convert probe, remove, suspend, resume, and runtime PM callbacks to use these helpers instead of direct clk_prepare_enable() and clk_disable_unprepare() calls. Pack 'clk_enabled' immediately after 'n_bytes' into the existing padding hole in struct driver_data, avoiding additional alignment padding. Assisted-by: Antigravity:gemini-3.8-flash sparse Signed-off-by: Shih-Yuan Lee <redacted> --- drivers/spi/spi-pxa2xx.c | 41 ++++++++++++++++++++++++++++++++-------- drivers/spi/spi-pxa2xx.h | 2 ++ 2 files changed, 35 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index b11e30589074..a9d19d9a5343 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c@@ -713,6 +713,31 @@ static void handle_bad_msg(struct driver_data *drv_data) dev_err(drv_data->ssp->dev, "bad message state in interrupt handler\n"); } +static int pxa2xx_spi_clk_enable(struct driver_data *drv_data) +{ + int ret = 0; + + mutex_lock(&drv_data->clk_lock); + if (!drv_data->clk_enabled) { + ret = clk_prepare_enable(drv_data->ssp->clk); + if (!ret) + drv_data->clk_enabled = true; + } + mutex_unlock(&drv_data->clk_lock); + + return ret; +} + +static void pxa2xx_spi_clk_disable(struct driver_data *drv_data) +{ + mutex_lock(&drv_data->clk_lock); + if (drv_data->clk_enabled) { + drv_data->clk_enabled = false; + clk_disable_unprepare(drv_data->ssp->clk); + } + mutex_unlock(&drv_data->clk_lock); +} + static irqreturn_t ssp_int(int irq, void *dev_id) { struct driver_data *drv_data = dev_id;
@@ -1288,6 +1313,7 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, drv_data->controller = controller; drv_data->controller_info = platform_info; drv_data->ssp = ssp; + mutex_init(&drv_data->clk_lock); /* The spi->mode bits understood by this driver: */ controller->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LOOP;
@@ -1352,7 +1378,7 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, } /* Enable SOC clock */ - ret = clk_prepare_enable(ssp->clk); + ret = pxa2xx_spi_clk_enable(drv_data); if (ret) goto out_error_dma_irq_alloc;
@@ -1449,7 +1475,7 @@ int pxa2xx_spi_probe(struct device *dev, struct ssp_device *ssp, return ret; out_error_clock_enabled: - clk_disable_unprepare(ssp->clk); + pxa2xx_spi_clk_disable(drv_data); out_error_dma_irq_alloc: pxa2xx_spi_dma_release(drv_data);
@@ -1468,7 +1494,7 @@ void pxa2xx_spi_remove(struct device *dev) /* Disable the SSP at the peripheral and SOC level */ pxa_ssp_disable(ssp); - clk_disable_unprepare(ssp->clk); + pxa2xx_spi_clk_disable(drv_data); /* Release DMA */ if (drv_data->controller_info->enable_dma)
@@ -1492,7 +1518,7 @@ static int pxa2xx_spi_suspend(struct device *dev) pxa_ssp_disable(ssp); if (!pm_runtime_suspended(dev)) - clk_disable_unprepare(ssp->clk); + pxa2xx_spi_clk_disable(drv_data); return 0; }
@@ -1500,12 +1526,11 @@ static int pxa2xx_spi_suspend(struct device *dev) static int pxa2xx_spi_resume(struct device *dev) { struct driver_data *drv_data = dev_get_drvdata(dev); - struct ssp_device *ssp = drv_data->ssp; int ret; /* Enable the SSP clock */ if (!pm_runtime_suspended(dev)) { - ret = clk_prepare_enable(ssp->clk); + ret = pxa2xx_spi_clk_enable(drv_data); if (ret) return ret; }
@@ -1518,7 +1543,7 @@ static int pxa2xx_spi_runtime_suspend(struct device *dev) { struct driver_data *drv_data = dev_get_drvdata(dev); - clk_disable_unprepare(drv_data->ssp->clk); + pxa2xx_spi_clk_disable(drv_data); return 0; }
@@ -1526,7 +1551,7 @@ static int pxa2xx_spi_runtime_resume(struct device *dev) { struct driver_data *drv_data = dev_get_drvdata(dev); - return clk_prepare_enable(drv_data->ssp->clk); + return pxa2xx_spi_clk_enable(drv_data); } EXPORT_NS_GPL_DEV_PM_OPS(pxa2xx_spi_pm_ops, SPI_PXA2xx) = {
diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
index 447be0369384..3352239f74a0 100644
--- a/drivers/spi/spi-pxa2xx.h
+++ b/drivers/spi/spi-pxa2xx.h@@ -66,6 +66,8 @@ struct driver_data { void *rx; void *rx_end; u8 n_bytes; + bool clk_enabled; + struct mutex clk_lock; int (*write)(struct driver_data *drv_data); int (*read)(struct driver_data *drv_data); irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
--
2.39.5