diff options
Diffstat (limited to 'drivers/counter')
| -rw-r--r-- | drivers/counter/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/counter/Makefile | 1 | ||||
| -rw-r--r-- | drivers/counter/ftm-quaddec.c | 356 |
3 files changed, 366 insertions, 0 deletions
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig index 87c491a19c63..233ac305d878 100644 --- a/drivers/counter/Kconfig +++ b/drivers/counter/Kconfig @@ -48,4 +48,13 @@ config STM32_LPTIMER_CNT To compile this driver as a module, choose M here: the module will be called stm32-lptimer-cnt. +config FTM_QUADDEC + tristate "Flex Timer Module Quadrature decoder driver" + help + Select this option to enable the Flex Timer Quadrature decoder + driver. + + To compile this driver as a module, choose M here: the + module will be called ftm-quaddec. + endif # COUNTER diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile index 5589976d37f8..0c9e622a6bea 100644 --- a/drivers/counter/Makefile +++ b/drivers/counter/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_COUNTER) += counter.o obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o +obj-$(CONFIG_FTM_QUADDEC) += ftm-quaddec.o diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c new file mode 100644 index 000000000000..c83c8875bf82 --- /dev/null +++ b/drivers/counter/ftm-quaddec.c @@ -0,0 +1,356 @@ +// 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(struct ftm_quaddec *ftm) +{ + ftm_clear_write_protection(ftm); + ftm_write(ftm, FTM_MODE, 0); + ftm_write(ftm, 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); +} + +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 = counter_register(&ftm->counter); + if (ret) + ftm_quaddec_disable(ftm); + + return ret; +} + +static int ftm_quaddec_remove(struct platform_device *pdev) +{ + struct ftm_quaddec *ftm = platform_get_drvdata(pdev); + + counter_unregister(&ftm->counter); + + ftm_quaddec_disable(ftm); + + 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, + .remove = ftm_quaddec_remove, +}; + +module_platform_driver(ftm_quaddec_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Kjeld Flarup <kfa@deif.com"); +MODULE_AUTHOR("Patrick Havelange <patrick.havelange@essensium.com"); |