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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Flex Timer Module Quadrature decoder
- *
- * This module implements a driver for decoding the FTM quadrature
- * of ex. a LS1021A
- */
- #include <linux/fsl/ftm.h>
- #include <linux/module.h>
- #include <linux/platform_device.h>
- #include <linux/of.h>
- #include <linux/io.h>
- #include <linux/mutex.h>
- #include <linux/counter.h>
- #include <linux/bitfield.h>
- #define FTM_FIELD_UPDATE(ftm, offset, mask, val) \
- ({ \
- uint32_t flags; \
- ftm_read(ftm, offset, &flags); \
- flags &= ~mask; \
- flags |= FIELD_PREP(mask, val); \
- ftm_write(ftm, offset, flags); \
- })
- struct ftm_quaddec {
- struct counter_device counter;
- struct platform_device *pdev;
- void __iomem *ftm_base;
- bool big_endian;
- struct mutex ftm_quaddec_mutex;
- };
- static void ftm_read(struct ftm_quaddec *ftm, uint32_t offset, uint32_t *data)
- {
- if (ftm->big_endian)
- *data = ioread32be(ftm->ftm_base + offset);
- else
- *data = ioread32(ftm->ftm_base + offset);
- }
- static void ftm_write(struct ftm_quaddec *ftm, uint32_t offset, uint32_t data)
- {
- if (ftm->big_endian)
- iowrite32be(data, ftm->ftm_base + offset);
- else
- iowrite32(data, ftm->ftm_base + offset);
- }
- /* Hold mutex before modifying write protection state */
- static void ftm_clear_write_protection(struct ftm_quaddec *ftm)
- {
- uint32_t flag;
- /* First see if it is enabled */
- ftm_read(ftm, FTM_FMS, &flag);
- if (flag & FTM_FMS_WPEN)
- FTM_FIELD_UPDATE(ftm, FTM_MODE, FTM_MODE_WPDIS, 1);
- }
- static void ftm_set_write_protection(struct ftm_quaddec *ftm)
- {
- FTM_FIELD_UPDATE(ftm, FTM_FMS, FTM_FMS_WPEN, 1);
- }
- static void ftm_reset_counter(struct ftm_quaddec *ftm)
- {
- /* Reset hardware counter to CNTIN */
- ftm_write(ftm, FTM_CNT, 0x0);
- }
- static void ftm_quaddec_init(struct ftm_quaddec *ftm)
- {
- ftm_clear_write_protection(ftm);
- /*
- * Do not write in the region from the CNTIN register through the
- * PWMLOAD register when FTMEN = 0.
- * Also reset other fields to zero
- */
- ftm_write(ftm, FTM_MODE, FTM_MODE_FTMEN);
- ftm_write(ftm, FTM_CNTIN, 0x0000);
- ftm_write(ftm, FTM_MOD, 0xffff);
- ftm_write(ftm, FTM_CNT, 0x0);
- /* Set prescaler, reset other fields to zero */
- ftm_write(ftm, FTM_SC, FTM_SC_PS_1);
- /* Select quad mode, reset other fields to zero */
- ftm_write(ftm, FTM_QDCTRL, FTM_QDCTRL_QUADEN);
- /* Unused features and reset to default section */
- ftm_write(ftm, FTM_POL, 0x0);
- ftm_write(ftm, FTM_FLTCTRL, 0x0);
- ftm_write(ftm, FTM_SYNCONF, 0x0);
- ftm_write(ftm, FTM_SYNC, 0xffff);
- /* Lock the FTM */
- ftm_set_write_protection(ftm);
- }
- static void ftm_quaddec_disable(void *ftm)
- {
- struct ftm_quaddec *ftm_qua = ftm;
- ftm_clear_write_protection(ftm_qua);
- ftm_write(ftm_qua, FTM_MODE, 0);
- ftm_write(ftm_qua, FTM_QDCTRL, 0);
- /*
- * This is enough to disable the counter. No clock has been
- * selected by writing to FTM_SC in init()
- */
- ftm_set_write_protection(ftm_qua);
- }
- static int ftm_quaddec_get_prescaler(struct counter_device *counter,
- struct counter_count *count,
- size_t *cnt_mode)
- {
- struct ftm_quaddec *ftm = counter->priv;
- uint32_t scflags;
- ftm_read(ftm, FTM_SC, &scflags);
- *cnt_mode = FIELD_GET(FTM_SC_PS_MASK, scflags);
- return 0;
- }
- static int ftm_quaddec_set_prescaler(struct counter_device *counter,
- struct counter_count *count,
- size_t cnt_mode)
- {
- struct ftm_quaddec *ftm = counter->priv;
- mutex_lock(&ftm->ftm_quaddec_mutex);
- ftm_clear_write_protection(ftm);
- FTM_FIELD_UPDATE(ftm, FTM_SC, FTM_SC_PS_MASK, cnt_mode);
- ftm_set_write_protection(ftm);
- /* Also resets the counter as it is undefined anyway now */
- ftm_reset_counter(ftm);
- mutex_unlock(&ftm->ftm_quaddec_mutex);
- return 0;
- }
- static const char * const ftm_quaddec_prescaler[] = {
- "1", "2", "4", "8", "16", "32", "64", "128"
- };
- static struct counter_count_enum_ext ftm_quaddec_prescaler_enum = {
- .items = ftm_quaddec_prescaler,
- .num_items = ARRAY_SIZE(ftm_quaddec_prescaler),
- .get = ftm_quaddec_get_prescaler,
- .set = ftm_quaddec_set_prescaler
- };
- enum ftm_quaddec_synapse_action {
- FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
- };
- static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
- [FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
- COUNTER_SYNAPSE_ACTION_BOTH_EDGES
- };
- enum ftm_quaddec_count_function {
- FTM_QUADDEC_COUNT_ENCODER_MODE_1,
- };
- static const enum counter_count_function ftm_quaddec_count_functions[] = {
- [FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
- COUNTER_COUNT_FUNCTION_QUADRATURE_X4
- };
- static int ftm_quaddec_count_read(struct counter_device *counter,
- struct counter_count *count,
- struct counter_count_read_value *val)
- {
- struct ftm_quaddec *const ftm = counter->priv;
- uint32_t cntval;
- ftm_read(ftm, FTM_CNT, &cntval);
- counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cntval);
- return 0;
- }
- static int ftm_quaddec_count_write(struct counter_device *counter,
- struct counter_count *count,
- struct counter_count_write_value *val)
- {
- struct ftm_quaddec *const ftm = counter->priv;
- u32 cnt;
- int err;
- err = counter_count_write_value_get(&cnt, COUNTER_COUNT_POSITION, val);
- if (err)
- return err;
- if (cnt != 0) {
- dev_warn(&ftm->pdev->dev, "Can only accept '0' as new counter value\n");
- return -EINVAL;
- }
- ftm_reset_counter(ftm);
- return 0;
- }
- static int ftm_quaddec_count_function_get(struct counter_device *counter,
- struct counter_count *count,
- size_t *function)
- {
- *function = FTM_QUADDEC_COUNT_ENCODER_MODE_1;
- return 0;
- }
- static int ftm_quaddec_action_get(struct counter_device *counter,
- struct counter_count *count,
- struct counter_synapse *synapse,
- size_t *action)
- {
- *action = FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES;
- return 0;
- }
- static const struct counter_ops ftm_quaddec_cnt_ops = {
- .count_read = ftm_quaddec_count_read,
- .count_write = ftm_quaddec_count_write,
- .function_get = ftm_quaddec_count_function_get,
- .action_get = ftm_quaddec_action_get,
- };
- static struct counter_signal ftm_quaddec_signals[] = {
- {
- .id = 0,
- .name = "Channel 1 Phase A"
- },
- {
- .id = 1,
- .name = "Channel 1 Phase B"
- }
- };
- static struct counter_synapse ftm_quaddec_count_synapses[] = {
- {
- .actions_list = ftm_quaddec_synapse_actions,
- .num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions),
- .signal = &ftm_quaddec_signals[0]
- },
- {
- .actions_list = ftm_quaddec_synapse_actions,
- .num_actions = ARRAY_SIZE(ftm_quaddec_synapse_actions),
- .signal = &ftm_quaddec_signals[1]
- }
- };
- static const struct counter_count_ext ftm_quaddec_count_ext[] = {
- COUNTER_COUNT_ENUM("prescaler", &ftm_quaddec_prescaler_enum),
- COUNTER_COUNT_ENUM_AVAILABLE("prescaler", &ftm_quaddec_prescaler_enum),
- };
- static struct counter_count ftm_quaddec_counts = {
- .id = 0,
- .name = "Channel 1 Count",
- .functions_list = ftm_quaddec_count_functions,
- .num_functions = ARRAY_SIZE(ftm_quaddec_count_functions),
- .synapses = ftm_quaddec_count_synapses,
- .num_synapses = ARRAY_SIZE(ftm_quaddec_count_synapses),
- .ext = ftm_quaddec_count_ext,
- .num_ext = ARRAY_SIZE(ftm_quaddec_count_ext)
- };
- static int ftm_quaddec_probe(struct platform_device *pdev)
- {
- struct ftm_quaddec *ftm;
- struct device_node *node = pdev->dev.of_node;
- struct resource *io;
- int ret;
- ftm = devm_kzalloc(&pdev->dev, sizeof(*ftm), GFP_KERNEL);
- if (!ftm)
- return -ENOMEM;
- platform_set_drvdata(pdev, ftm);
- io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!io) {
- dev_err(&pdev->dev, "Failed to get memory region\n");
- return -ENODEV;
- }
- ftm->pdev = pdev;
- ftm->big_endian = of_property_read_bool(node, "big-endian");
- ftm->ftm_base = devm_ioremap(&pdev->dev, io->start, resource_size(io));
- if (!ftm->ftm_base) {
- dev_err(&pdev->dev, "Failed to map memory region\n");
- return -EINVAL;
- }
- ftm->counter.name = dev_name(&pdev->dev);
- ftm->counter.parent = &pdev->dev;
- ftm->counter.ops = &ftm_quaddec_cnt_ops;
- ftm->counter.counts = &ftm_quaddec_counts;
- ftm->counter.num_counts = 1;
- ftm->counter.signals = ftm_quaddec_signals;
- ftm->counter.num_signals = ARRAY_SIZE(ftm_quaddec_signals);
- ftm->counter.priv = ftm;
- mutex_init(&ftm->ftm_quaddec_mutex);
- ftm_quaddec_init(ftm);
- ret = devm_add_action_or_reset(&pdev->dev, ftm_quaddec_disable, ftm);
- if (ret)
- return ret;
- ret = devm_counter_register(&pdev->dev, &ftm->counter);
- if (ret)
- return ret;
- return 0;
- }
- static const struct of_device_id ftm_quaddec_match[] = {
- { .compatible = "fsl,ftm-quaddec" },
- {},
- };
- static struct platform_driver ftm_quaddec_driver = {
- .driver = {
- .name = "ftm-quaddec",
- .of_match_table = ftm_quaddec_match,
- },
- .probe = ftm_quaddec_probe,
- };
- module_platform_driver(ftm_quaddec_driver);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Kjeld Flarup <kfa@deif.com>");
- MODULE_AUTHOR("Patrick Havelange <patrick.havelange@essensium.com>");
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