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path: root/drivers/mfd/stm32-timers.c
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Diffstat (limited to 'drivers/mfd/stm32-timers.c')
-rw-r--r--drivers/mfd/stm32-timers.c294
1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
new file mode 100644
index 000000000..44ed2fce0
--- /dev/null
+++ b/drivers/mfd/stm32-timers.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2016
+ * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/mfd/stm32-timers.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/reset.h>
+
+#define STM32_TIMERS_MAX_REGISTERS 0x3fc
+
+/* DIER register DMA enable bits */
+static const u32 stm32_timers_dier_dmaen[STM32_TIMERS_MAX_DMAS] = {
+ TIM_DIER_CC1DE,
+ TIM_DIER_CC2DE,
+ TIM_DIER_CC3DE,
+ TIM_DIER_CC4DE,
+ TIM_DIER_UIE,
+ TIM_DIER_TDE,
+ TIM_DIER_COMDE
+};
+
+static void stm32_timers_dma_done(void *p)
+{
+ struct stm32_timers_dma *dma = p;
+ struct dma_tx_state state;
+ enum dma_status status;
+
+ status = dmaengine_tx_status(dma->chan, dma->chan->cookie, &state);
+ if (status == DMA_COMPLETE)
+ complete(&dma->completion);
+}
+
+/**
+ * stm32_timers_dma_burst_read - Read from timers registers using DMA.
+ *
+ * Read from STM32 timers registers using DMA on a single event.
+ * @dev: reference to stm32_timers MFD device
+ * @buf: DMA'able destination buffer
+ * @id: stm32_timers_dmas event identifier (ch[1..4], up, trig or com)
+ * @reg: registers start offset for DMA to read from (like CCRx for capture)
+ * @num_reg: number of registers to read upon each DMA request, starting @reg.
+ * @bursts: number of bursts to read (e.g. like two for pwm period capture)
+ * @tmo_ms: timeout (milliseconds)
+ */
+int stm32_timers_dma_burst_read(struct device *dev, u32 *buf,
+ enum stm32_timers_dmas id, u32 reg,
+ unsigned int num_reg, unsigned int bursts,
+ unsigned long tmo_ms)
+{
+ struct stm32_timers *ddata = dev_get_drvdata(dev);
+ unsigned long timeout = msecs_to_jiffies(tmo_ms);
+ struct regmap *regmap = ddata->regmap;
+ struct stm32_timers_dma *dma = &ddata->dma;
+ size_t len = num_reg * bursts * sizeof(u32);
+ struct dma_async_tx_descriptor *desc;
+ struct dma_slave_config config;
+ dma_cookie_t cookie;
+ dma_addr_t dma_buf;
+ u32 dbl, dba;
+ long err;
+ int ret;
+
+ /* Sanity check */
+ if (id < STM32_TIMERS_DMA_CH1 || id >= STM32_TIMERS_MAX_DMAS)
+ return -EINVAL;
+
+ if (!num_reg || !bursts || reg > STM32_TIMERS_MAX_REGISTERS ||
+ (reg + num_reg * sizeof(u32)) > STM32_TIMERS_MAX_REGISTERS)
+ return -EINVAL;
+
+ if (!dma->chans[id])
+ return -ENODEV;
+ mutex_lock(&dma->lock);
+
+ /* Select DMA channel in use */
+ dma->chan = dma->chans[id];
+ dma_buf = dma_map_single(dev, buf, len, DMA_FROM_DEVICE);
+ if (dma_mapping_error(dev, dma_buf)) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ /* Prepare DMA read from timer registers, using DMA burst mode */
+ memset(&config, 0, sizeof(config));
+ config.src_addr = (dma_addr_t)dma->phys_base + TIM_DMAR;
+ config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ ret = dmaengine_slave_config(dma->chan, &config);
+ if (ret)
+ goto unmap;
+
+ desc = dmaengine_prep_slave_single(dma->chan, dma_buf, len,
+ DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
+ if (!desc) {
+ ret = -EBUSY;
+ goto unmap;
+ }
+
+ desc->callback = stm32_timers_dma_done;
+ desc->callback_param = dma;
+ cookie = dmaengine_submit(desc);
+ ret = dma_submit_error(cookie);
+ if (ret)
+ goto dma_term;
+
+ reinit_completion(&dma->completion);
+ dma_async_issue_pending(dma->chan);
+
+ /* Setup and enable timer DMA burst mode */
+ dbl = FIELD_PREP(TIM_DCR_DBL, bursts - 1);
+ dba = FIELD_PREP(TIM_DCR_DBA, reg >> 2);
+ ret = regmap_write(regmap, TIM_DCR, dbl | dba);
+ if (ret)
+ goto dma_term;
+
+ /* Clear pending flags before enabling DMA request */
+ ret = regmap_write(regmap, TIM_SR, 0);
+ if (ret)
+ goto dcr_clr;
+
+ ret = regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id],
+ stm32_timers_dier_dmaen[id]);
+ if (ret)
+ goto dcr_clr;
+
+ err = wait_for_completion_interruptible_timeout(&dma->completion,
+ timeout);
+ if (err == 0)
+ ret = -ETIMEDOUT;
+ else if (err < 0)
+ ret = err;
+
+ regmap_update_bits(regmap, TIM_DIER, stm32_timers_dier_dmaen[id], 0);
+ regmap_write(regmap, TIM_SR, 0);
+dcr_clr:
+ regmap_write(regmap, TIM_DCR, 0);
+dma_term:
+ dmaengine_terminate_all(dma->chan);
+unmap:
+ dma_unmap_single(dev, dma_buf, len, DMA_FROM_DEVICE);
+unlock:
+ dma->chan = NULL;
+ mutex_unlock(&dma->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(stm32_timers_dma_burst_read);
+
+static const struct regmap_config stm32_timers_regmap_cfg = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = sizeof(u32),
+ .max_register = STM32_TIMERS_MAX_REGISTERS,
+};
+
+static void stm32_timers_get_arr_size(struct stm32_timers *ddata)
+{
+ u32 arr;
+
+ /* Backup ARR to restore it after getting the maximum value */
+ regmap_read(ddata->regmap, TIM_ARR, &arr);
+
+ /*
+ * Only the available bits will be written so when readback
+ * we get the maximum value of auto reload register
+ */
+ regmap_write(ddata->regmap, TIM_ARR, ~0L);
+ regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr);
+ regmap_write(ddata->regmap, TIM_ARR, arr);
+}
+
+static int stm32_timers_dma_probe(struct device *dev,
+ struct stm32_timers *ddata)
+{
+ int i;
+ int ret = 0;
+ char name[4];
+
+ init_completion(&ddata->dma.completion);
+ mutex_init(&ddata->dma.lock);
+
+ /* Optional DMA support: get valid DMA channel(s) or NULL */
+ for (i = STM32_TIMERS_DMA_CH1; i <= STM32_TIMERS_DMA_CH4; i++) {
+ snprintf(name, ARRAY_SIZE(name), "ch%1d", i + 1);
+ ddata->dma.chans[i] = dma_request_chan(dev, name);
+ }
+ ddata->dma.chans[STM32_TIMERS_DMA_UP] = dma_request_chan(dev, "up");
+ ddata->dma.chans[STM32_TIMERS_DMA_TRIG] = dma_request_chan(dev, "trig");
+ ddata->dma.chans[STM32_TIMERS_DMA_COM] = dma_request_chan(dev, "com");
+
+ for (i = STM32_TIMERS_DMA_CH1; i < STM32_TIMERS_MAX_DMAS; i++) {
+ if (IS_ERR(ddata->dma.chans[i])) {
+ /* Save the first error code to return */
+ if (PTR_ERR(ddata->dma.chans[i]) != -ENODEV && !ret)
+ ret = PTR_ERR(ddata->dma.chans[i]);
+
+ ddata->dma.chans[i] = NULL;
+ }
+ }
+
+ return ret;
+}
+
+static void stm32_timers_dma_remove(struct device *dev,
+ struct stm32_timers *ddata)
+{
+ int i;
+
+ for (i = STM32_TIMERS_DMA_CH1; i < STM32_TIMERS_MAX_DMAS; i++)
+ if (ddata->dma.chans[i])
+ dma_release_channel(ddata->dma.chans[i]);
+}
+
+static int stm32_timers_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct stm32_timers *ddata;
+ struct resource *res;
+ void __iomem *mmio;
+ int ret;
+
+ ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mmio = devm_ioremap_resource(dev, res);
+ if (IS_ERR(mmio))
+ return PTR_ERR(mmio);
+
+ /* Timer physical addr for DMA */
+ ddata->dma.phys_base = res->start;
+
+ ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio,
+ &stm32_timers_regmap_cfg);
+ if (IS_ERR(ddata->regmap))
+ return PTR_ERR(ddata->regmap);
+
+ ddata->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(ddata->clk))
+ return PTR_ERR(ddata->clk);
+
+ stm32_timers_get_arr_size(ddata);
+
+ ret = stm32_timers_dma_probe(dev, ddata);
+ if (ret) {
+ stm32_timers_dma_remove(dev, ddata);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, ddata);
+
+ ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
+ if (ret)
+ stm32_timers_dma_remove(dev, ddata);
+
+ return ret;
+}
+
+static int stm32_timers_remove(struct platform_device *pdev)
+{
+ struct stm32_timers *ddata = platform_get_drvdata(pdev);
+
+ /*
+ * Don't use devm_ here: enfore of_platform_depopulate() happens before
+ * DMA are released, to avoid race on DMA.
+ */
+ of_platform_depopulate(&pdev->dev);
+ stm32_timers_dma_remove(&pdev->dev, ddata);
+
+ return 0;
+}
+
+static const struct of_device_id stm32_timers_of_match[] = {
+ { .compatible = "st,stm32-timers", },
+ { /* end node */ },
+};
+MODULE_DEVICE_TABLE(of, stm32_timers_of_match);
+
+static struct platform_driver stm32_timers_driver = {
+ .probe = stm32_timers_probe,
+ .remove = stm32_timers_remove,
+ .driver = {
+ .name = "stm32-timers",
+ .of_match_table = stm32_timers_of_match,
+ },
+};
+module_platform_driver(stm32_timers_driver);
+
+MODULE_DESCRIPTION("STMicroelectronics STM32 Timers");
+MODULE_LICENSE("GPL v2");