On Thu, Apr 09, 2020 at 10:25:31AM +0200, Kamel Bouhara wrote: > On Wed, Apr 08, 2020 at 05:31:03PM -0400, William Breathitt Gray wrote: > > On Mon, Apr 06, 2020 at 05:53:20PM +0200, Kamel Bouhara wrote: > > > This drivers allows to use the capture mode of the Timer Counter Block > > > hardware block available in Atmel SoCs through the counter subsystem. > > > > > > Two functions of the counter are supported for the moment: period > > > capture and quadrature decoder. The latter is only supported by the > > > SAMA5 series of SoCs. > > > > > > For the period capture mode a basic setup has been chosen that will > > > reset the counter each time the period is actually reached. Of course > > > the device offers much more possibilities. > > > > > > For quadrature mode, both channel 0 and 1 must be configured even if we > > > only capture the position (no revolution/rotation). > > > > > > Signed-off-by: Kamel Bouhara > > > > Hi Kamel, > > > > Hi William, > > > Thank you for submitting support for this driver. Since this is a new > > counter driver, make sure to create an entry for it in the top-level > > MAINTAINERS file so users know who to contact to report bugs and other > > issues. > > > > I'll skip this if you're ok with the fact that the file name already > match the at91 maintainers ? No problem, you can skip this, I didn't realize it was already matching. William Breathitt Gray > > > I've written some more comments inline below. > > > > > --- > > > drivers/counter/Kconfig | 11 + > > > drivers/counter/Makefile | 1 + > > > drivers/counter/atmel-tcb-capture.c | 388 ++++++++++++++++++++++++++++ > > > 3 files changed, 400 insertions(+) > > > create mode 100644 drivers/counter/atmel-tcb-capture.c > > > > > > diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig > > > index c80fa76bb531..c50d7453ec33 100644 > > > --- a/drivers/counter/Kconfig > > > +++ b/drivers/counter/Kconfig > > > @@ -70,4 +70,15 @@ config FTM_QUADDEC > > > To compile this driver as a module, choose M here: the > > > module will be called ftm-quaddec. > > > > > > +config ATMEL_TCB_CAPTURE > > > + tristate "Atmel Timer Counter Capture driver" > > > + depends on HAS_IOMEM && OF > > > + select REGMAP_MMIO > > > + help > > > + Select this option to enable the Atmel Timer Counter Block > > > + capture driver. > > > + > > > + To compile this driver as a module, choose M here: the > > > + module will be called atmel-tcb-capture. > > > + > > > endif # COUNTER > > > diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile > > > index 55142d1f4c43..70c5b8924588 100644 > > > --- a/drivers/counter/Makefile > > > +++ b/drivers/counter/Makefile > > > @@ -10,3 +10,4 @@ obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o > > > obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o > > > obj-$(CONFIG_TI_EQEP) += ti-eqep.o > > > obj-$(CONFIG_FTM_QUADDEC) += ftm-quaddec.o > > > +obj-$(CONFIG_ATMEL_TCB_CAPTURE) += atmel-tcb-capture.o > > > diff --git a/drivers/counter/atmel-tcb-capture.c b/drivers/counter/atmel-tcb-capture.c > > > new file mode 100644 > > > index 000000000000..6ac809503f90 > > > --- /dev/null > > > +++ b/drivers/counter/atmel-tcb-capture.c > > > @@ -0,0 +1,388 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/** > > > + * Copyright (C) 2020 Atmel > > > + * > > > + * Author: Kamel Bouhara > > > + * > > > + */ > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > +#include > > > + > > > +#define ATMEL_TC_CMR_MASK (ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \ > > > + ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \ > > > + ATMEL_TC_LDBSTOP) > > > + > > > +#define ATMEL_TC_QDEN BIT(8) > > > +#define ATMEL_TC_POSEN BIT(9) > > > + > > > +struct atmel_tc_data { > > > + const struct atmel_tcb_config *tc_cfg; > > > + struct counter_device counter; > > > + struct regmap *regmap; > > > + int qdec_mode; > > > + int num_channels; > > > + int channel[2]; > > > + bool trig_inverted; > > > +}; > > > + > > > +enum atmel_tc_count_function { > > > + ATMEL_TC_FUNCTION_INCREASE, > > > + ATMEL_TC_FUNCTION_QUADRATURE, > > > +}; > > > + > > > +static enum counter_count_function atmel_tc_count_functions[] = { > > > + [ATMEL_TC_FUNCTION_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE, > > > + [ATMEL_TC_FUNCTION_QUADRATURE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4, > > > +}; > > > + > > > +enum atmel_tc_synapse_action { > > > + ATMEL_TC_SYNAPSE_ACTION_NONE = 0, > > > + ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE, > > > + ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE, > > > + ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE > > > +}; > > > + > > > +static enum counter_synapse_action atmel_tc_synapse_actions[] = { > > > + [ATMEL_TC_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE, > > > + [ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE, > > > + [ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE, > > > + [ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES, > > > +}; > > > + > > > +static struct counter_signal atmel_tc_count_signals[] = { > > > + { > > > + .id = 0, > > > + .name = "Channel A", > > > + }, > > > + { > > > + .id = 1, > > > + .name = "Channel B", > > > + } > > > +}; > > > + > > > +static struct counter_synapse atmel_tc_count_synapses[] = { > > > + { > > > + .actions_list = atmel_tc_synapse_actions, > > > + .num_actions = ARRAY_SIZE(atmel_tc_synapse_actions), > > > + .signal = &atmel_tc_count_signals[0] > > > + }, > > > + { > > > + .actions_list = atmel_tc_synapse_actions, > > > + .num_actions = ARRAY_SIZE(atmel_tc_synapse_actions), > > > + .signal = &atmel_tc_count_signals[1] > > > + } > > > +}; > > > + > > > +static int atmel_tc_count_function_get(struct counter_device *counter, > > > + struct counter_count *count, > > > + size_t *function) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + > > > + if (priv->qdec_mode) > > > + *function = ATMEL_TC_FUNCTION_QUADRATURE; > > > + else > > > + *function = ATMEL_TC_FUNCTION_INCREASE; > > > + > > > + return 0; > > > +} > > > + > > > +static int atmel_tc_count_function_set(struct counter_device *counter, > > > + struct counter_count *count, > > > + size_t function) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + u32 bmr, cmr; > > > + > > > + regmap_read(priv->regmap, ATMEL_TC_BMR, &bmr); > > > + regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr); > > > + > > > + /* Set capture mode */ > > > + cmr &= ~ATMEL_TC_WAVE; > > > + > > > + switch (function) { > > > + case ATMEL_TC_FUNCTION_INCREASE: > > > + priv->qdec_mode = 0; > > > + /* Set highest rate based on whether soc has gclk or not */ > > > + bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN); > > > + if (priv->tc_cfg->has_gclk) > > > + cmr |= ATMEL_TC_TIMER_CLOCK2; > > > + else > > > + cmr |= ATMEL_TC_TIMER_CLOCK1; > > > + /* Setup the period capture mode */ > > > + cmr |= ATMEL_TC_CMR_MASK; > > > + cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0); > > > + break; > > > + case ATMEL_TC_FUNCTION_QUADRATURE: > > > + if (!priv->tc_cfg->has_qdec) > > > + return -ENODEV; > > > > I think returning an -EINVAL here might be better. I can understand that > > the system does not have a quadrature encoder device in this case, but > > from the user perspective they are requesting to set the function for > > the existing counter device. Therefore, if the existing counter device > > does not support the requested function, it makes sense to report the > > issue as simply an invalid argument (return -EINVAL) for this particular > > device. > > > > Good point, fixed for v2. > > > > + /* In QDEC mode settings both channels 0 and 1 are required */ > > > + if (priv->num_channels < 2 || priv->channel[0] != 0 || > > > + priv->channel[1] != 1) { > > > + pr_err("Invalid channels number or id for quadrature mode\n"); > > > + return -EINVAL; > > > + } > > > + priv->qdec_mode = 1; > > > + bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN; > > > + cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0; > > > + break; > > > + } > > > + > > > + regmap_write(priv->regmap, ATMEL_TC_BMR, bmr); > > > + regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), cmr); > > > + > > > + /* Enable clock and trigger counter */ > > > + regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CCR), > > > + ATMEL_TC_CLKEN | ATMEL_TC_SWTRG); > > > + > > > + if (priv->qdec_mode) { > > > + regmap_write(priv->regmap, > > > + ATMEL_TC_REG(priv->channel[1], CMR), cmr); > > > + regmap_write(priv->regmap, > > > + ATMEL_TC_REG(priv->channel[1], CCR), > > > + ATMEL_TC_CLKEN | ATMEL_TC_SWTRG); > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +static int atmel_tc_count_signal_read(struct counter_device *counter, > > > + struct counter_signal *signal, > > > + enum counter_signal_value *val) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + bool sigstatus; > > > + u32 sr; > > > + > > > + regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr); > > > + > > > + if (priv->trig_inverted) > > > + sigstatus = (sr & ATMEL_TC_MTIOB); > > > + else > > > + sigstatus = (sr & ATMEL_TC_MTIOA); > > > + > > > + *val = sigstatus ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW; > > > + > > > + return 0; > > > +} > > > + > > > +static int atmel_tc_count_action_get(struct counter_device *counter, > > > + struct counter_count *count, > > > + struct counter_synapse *synapse, > > > + size_t *action) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + u32 cmr; > > > + > > > + regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr); > > > + > > > + *action = ATMEL_TC_SYNAPSE_ACTION_NONE; > > > + > > > + if (cmr & ATMEL_TC_ETRGEDG_NONE) > > > + *action = ATMEL_TC_SYNAPSE_ACTION_NONE; > > > + else if (cmr & ATMEL_TC_ETRGEDG_RISING) > > > + *action = ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE; > > > + else if (cmr & ATMEL_TC_ETRGEDG_FALLING) > > > + *action = ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE; > > > + else if (cmr & ATMEL_TC_ETRGEDG_BOTH) > > > + *action = ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE; > > > + > > > + return 0; > > > +} > > > + > > > +static int atmel_tc_count_action_set(struct counter_device *counter, > > > + struct counter_count *count, > > > + struct counter_synapse *synapse, > > > + size_t action) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + u32 edge = ATMEL_TC_ETRGEDG_NONE; > > > + > > > + switch (action) { > > > + case ATMEL_TC_SYNAPSE_ACTION_NONE: > > > + edge = ATMEL_TC_ETRGEDG_NONE; > > > + break; > > > + case ATMEL_TC_SYNAPSE_ACTION_RISING_EDGE: > > > + edge = ATMEL_TC_ETRGEDG_RISING; > > > + break; > > > + case ATMEL_TC_SYNAPSE_ACTION_FALLING_EDGE: > > > + edge = ATMEL_TC_ETRGEDG_FALLING; > > > + break; > > > + case ATMEL_TC_SYNAPSE_ACTION_BOTH_EDGE: > > > + edge = ATMEL_TC_ETRGEDG_BOTH; > > > + break; > > > + } > > > + > > > + return regmap_write_bits(priv->regmap, > > > + ATMEL_TC_REG(priv->channel[0], CMR), > > > + ATMEL_TC_ETRGEDG, edge); > > > > Are users able to adjust the edges like this even if the device is > > configured for QDEC mode? If not, you should return -EINVAL if the > > device is in QDEC mode. > > > > You're right, in QDEC mode, rising edge must be selected as the external > trigger edge. > > Fixed. > > > > +} > > > + > > > +static int atmel_tc_count_read(struct counter_device *counter, > > > + struct counter_count *count, > > > + unsigned long *val) > > > +{ > > > + struct atmel_tc_data *const priv = counter->priv; > > > + u32 cnt; > > > + > > > + regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CV), &cnt); > > > + *val = cnt; > > > + > > > + return 0; > > > +} > > > + > > > +static struct counter_count atmel_tc_count = { > > > + .id = 0, > > > + .name = "Timer Counter", > > > + .functions_list = atmel_tc_count_functions, > > > + .num_functions = ARRAY_SIZE(atmel_tc_count_functions), > > > + .synapses = atmel_tc_count_synapses, > > > + .num_synapses = ARRAY_SIZE(atmel_tc_count_synapses), > > > +}; > > > + > > > +static struct counter_ops atmel_tc_ops = { > > > + .signal_read = atmel_tc_count_signal_read, > > > + .count_read = atmel_tc_count_read, > > > + .count_write = NULL, > > > > No need to explicitly set count_write to NULL since it will be NULL by > > default in this static structure. > > > > Fixed, thanks. > > > > + .function_get = atmel_tc_count_function_get, > > > + .function_set = atmel_tc_count_function_set, > > > + .action_get = atmel_tc_count_action_get, > > > + .action_set = atmel_tc_count_action_set > > > +}; > > > + > > > +static const struct atmel_tcb_config tcb_rm9200_config = { > > > + .counter_width = 16, > > > +}; > > > + > > > +static const struct atmel_tcb_config tcb_sam9x5_config = { > > > + .counter_width = 32, > > > +}; > > > + > > > +static const struct atmel_tcb_config tcb_sama5d2_config = { > > > + .counter_width = 32, > > > + .has_gclk = true, > > > + .has_qdec = true, > > > +}; > > > + > > > +static const struct atmel_tcb_config tcb_sama5d3_config = { > > > + .counter_width = 32, > > > + .has_qdec = true, > > > +}; > > > + > > > +static const struct of_device_id atmel_tc_of_match[] = { > > > + { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, }, > > > + { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, }, > > > + { .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, }, > > > + { .compatible = "atmel,sama5d3-tcb", .data = &tcb_sama5d3_config, }, > > > + { /* sentinel */ } > > > +}; > > > + > > > +static int atmel_tc_probe(struct platform_device *pdev) > > > +{ > > > + struct device_node *np = pdev->dev.of_node; > > > + const struct atmel_tcb_config *tcb_config; > > > + const struct of_device_id *match; > > > + struct atmel_tc_data *priv; > > > + char clk_name[] = "t0_clk"; > > > + struct regmap *regmap; > > > + struct clk *clk[3]; > > > + int channel; > > > + int ret, i; > > > + > > > + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > > > + if (!priv) > > > + return -ENOMEM; > > > + > > > + platform_set_drvdata(pdev, priv); > > > + > > > + match = of_match_node(atmel_tc_of_match, np->parent); > > > + tcb_config = match->data; > > > + if (!tcb_config) { > > > + dev_err(&pdev->dev, "No matching parent node found\n"); > > > + return -ENODEV; > > > + } > > > + > > > + regmap = syscon_node_to_regmap(np->parent); > > > + if (IS_ERR(priv->regmap)) > > > + return PTR_ERR(priv->regmap); > > > + > > > + /* max. channels number is 2 when in QDEC mode */ > > > + priv->num_channels = of_property_count_u32_elems(np, "reg"); > > > + if (priv->num_channels < 0) { > > > + dev_err(&pdev->dev, "Invalid or missing channel\n"); > > > + return -EINVAL; > > > + } > > > + > > > + /* Register channels and initialize clocks */ > > > + for (i = 0; i < priv->num_channels; i++) { > > > + ret = of_property_read_u32_index(np, "reg", i, &channel); > > > + if (ret < 0 || channel > 2) > > > + return -ENODEV; > > > + > > > + priv->channel[i] = channel; > > > + > > > + clk_name[1] += channel; > > > > You're being clever here (not a bad thing) but this looks too easy to > > get wrong and confused. I'd much rather see a snprintf here for clarity > > and know that nothing funny is going to happen. > > > > Well ok let's be less clever for the sake of clarity :). > > > > + clk[i] = of_clk_get_by_name(np->parent, clk_name); > > > + if (IS_ERR(clk[i])) { > > > + /* Fallback to t0_clk */ > > > + clk[i] = of_clk_get_by_name(np->parent, "t0_clk"); > > > + if (IS_ERR(clk[i])) > > > + return PTR_ERR(clk[i]); > > > + } > > > + > > > + ret = clk_prepare_enable(clk[i]); > > > + if (ret) > > > + return ret; > > > + > > > + dev_info(&pdev->dev, > > > + "Initialized capture mode on channel %d\n", > > > + channel); > > > + } > > > + > > > + priv->tc_cfg = tcb_config; > > > + priv->regmap = regmap; > > > + priv->counter.name = dev_name(&pdev->dev); > > > + priv->counter.parent = &pdev->dev; > > > + priv->counter.ops = &atmel_tc_ops; > > > + priv->counter.num_counts = 1; > > > > Use ARRAY_SIZE here so that future reviewers will know that num_counts > > matches what's in the atmel_tc_count array without having to check so > > themselves. > > > > OK, yet the atmel_tc_count isn't an array I guess that it shall be. > > Thanks, > > Kamel > > > William Breathitt Gray > > > > > + priv->counter.counts = &atmel_tc_count; > > > + priv->counter.num_signals = ARRAY_SIZE(atmel_tc_count_signals); > > > + priv->counter.signals = atmel_tc_count_signals; > > > + priv->counter.priv = priv; > > > + > > > + ret = devm_counter_register(&pdev->dev, &priv->counter); > > > + if (ret < 0) { > > > + for (i = 0; i < priv->num_channels; i++) > > > + clk_disable_unprepare(clk[i]); > > > + return ret; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +static const struct of_device_id atmel_tc_dt_ids[] = { > > > + { .compatible = "atmel,tcb-capture", }, > > > + { /* sentinel */ }, > > > +}; > > > +MODULE_DEVICE_TABLE(of, atmel_tc_dt_ids); > > > + > > > +static struct platform_driver atmel_tc_driver = { > > > + .probe = atmel_tc_probe, > > > + .driver = { > > > + .name = "atmel-tcb-capture", > > > + .of_match_table = atmel_tc_dt_ids, > > > + }, > > > +}; > > > +module_platform_driver(atmel_tc_driver); > > > + > > > +MODULE_AUTHOR("Kamel Bouhara "); > > > +MODULE_DESCRIPTION("Atmel TCB Capture driver"); > > > +MODULE_LICENSE("GPL v2"); > > > -- > > > 2.25.0 > > > > > > > -- > Kamel Bouhara, Bootlin > Embedded Linux and kernel engineering > https://bootlin.com