/* * Driver for the ADC present in the Atmel AT91 evaluation boards. * * Copyright 2011 Free Electrons * * Licensed under the GPLv2 or later. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define AT91_ADC_CHAN(st, ch) \ (st->registers->channel_base + (ch * 4)) #define at91_adc_readl(st, reg) \ (readl_relaxed(st->reg_base + reg)) #define at91_adc_writel(st, reg, val) \ (writel_relaxed(val, st->reg_base + reg)) struct at91_adc_state { struct clk *adc_clk; u16 *buffer; unsigned long channels_mask; struct clk *clk; bool done; int irq; u16 last_value; struct mutex lock; u8 num_channels; void __iomem *reg_base; struct at91_adc_reg_desc *registers; u8 startup_time; u8 sample_hold_time; bool sleep_mode; struct iio_trigger **trig; struct at91_adc_trigger *trigger_list; u32 trigger_number; bool use_external; u32 vref_mv; u32 res; /* resolution used for convertions */ bool low_res; /* the resolution corresponds to the lowest one */ wait_queue_head_t wq_data_avail; }; static irqreturn_t at91_adc_trigger_handler(int irq, void *p) { struct iio_poll_func *pf = p; struct iio_dev *idev = pf->indio_dev; struct at91_adc_state *st = iio_priv(idev); int i, j = 0; for (i = 0; i < idev->masklength; i++) { if (!test_bit(i, idev->active_scan_mask)) continue; st->buffer[j] = at91_adc_readl(st, AT91_ADC_CHAN(st, i)); j++; } if (idev->scan_timestamp) { s64 *timestamp = (s64 *)((u8 *)st->buffer + ALIGN(j, sizeof(s64))); *timestamp = pf->timestamp; } iio_push_to_buffers(idev, (u8 *)st->buffer); iio_trigger_notify_done(idev->trig); /* Needed to ACK the DRDY interruption */ at91_adc_readl(st, AT91_ADC_LCDR); enable_irq(st->irq); return IRQ_HANDLED; } static irqreturn_t at91_adc_eoc_trigger(int irq, void *private) { struct iio_dev *idev = private; struct at91_adc_state *st = iio_priv(idev); u32 status = at91_adc_readl(st, st->registers->status_register); if (!(status & st->registers->drdy_mask)) return IRQ_HANDLED; if (iio_buffer_enabled(idev)) { disable_irq_nosync(irq); iio_trigger_poll(idev->trig, iio_get_time_ns()); } else { st->last_value = at91_adc_readl(st, AT91_ADC_LCDR); st->done = true; wake_up_interruptible(&st->wq_data_avail); } return IRQ_HANDLED; } static int at91_adc_channel_init(struct iio_dev *idev) { struct at91_adc_state *st = iio_priv(idev); struct iio_chan_spec *chan_array, *timestamp; int bit, idx = 0; idev->num_channels = bitmap_weight(&st->channels_mask, st->num_channels) + 1; chan_array = devm_kzalloc(&idev->dev, ((idev->num_channels + 1) * sizeof(struct iio_chan_spec)), GFP_KERNEL); if (!chan_array) return -ENOMEM; for_each_set_bit(bit, &st->channels_mask, st->num_channels) { struct iio_chan_spec *chan = chan_array + idx; chan->type = IIO_VOLTAGE; chan->indexed = 1; chan->channel = bit; chan->scan_index = idx; chan->scan_type.sign = 'u'; chan->scan_type.realbits = st->res; chan->scan_type.storagebits = 16; chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE); chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); idx++; } timestamp = chan_array + idx; timestamp->type = IIO_TIMESTAMP; timestamp->channel = -1; timestamp->scan_index = idx; timestamp->scan_type.sign = 's'; timestamp->scan_type.realbits = 64; timestamp->scan_type.storagebits = 64; idev->channels = chan_array; return idev->num_channels; } static u8 at91_adc_get_trigger_value_by_name(struct iio_dev *idev, struct at91_adc_trigger *triggers, const char *trigger_name) { struct at91_adc_state *st = iio_priv(idev); u8 value = 0; int i; for (i = 0; i < st->trigger_number; i++) { char *name = kasprintf(GFP_KERNEL, "%s-dev%d-%s", idev->name, idev->id, triggers[i].name); if (!name) return -ENOMEM; if (strcmp(trigger_name, name) == 0) { value = triggers[i].value; kfree(name); break; } kfree(name); } return value; } static int at91_adc_configure_trigger(struct iio_trigger *trig, bool state) { struct iio_dev *idev = iio_trigger_get_drvdata(trig); struct at91_adc_state *st = iio_priv(idev); struct iio_buffer *buffer = idev->buffer; struct at91_adc_reg_desc *reg = st->registers; u32 status = at91_adc_readl(st, reg->trigger_register); u8 value; u8 bit; value = at91_adc_get_trigger_value_by_name(idev, st->trigger_list, idev->trig->name); if (value == 0) return -EINVAL; if (state) { st->buffer = kmalloc(idev->scan_bytes, GFP_KERNEL); if (st->buffer == NULL) return -ENOMEM; at91_adc_writel(st, reg->trigger_register, status | value); for_each_set_bit(bit, buffer->scan_mask, st->num_channels) { struct iio_chan_spec const *chan = idev->channels + bit; at91_adc_writel(st, AT91_ADC_CHER, AT91_ADC_CH(chan->channel)); } at91_adc_writel(st, AT91_ADC_IER, reg->drdy_mask); } else { at91_adc_writel(st, AT91_ADC_IDR, reg->drdy_mask); at91_adc_writel(st, reg->trigger_register, status & ~value); for_each_set_bit(bit, buffer->scan_mask, st->num_channels) { struct iio_chan_spec const *chan = idev->channels + bit; at91_adc_writel(st, AT91_ADC_CHDR, AT91_ADC_CH(chan->channel)); } kfree(st->buffer); } return 0; } static const struct iio_trigger_ops at91_adc_trigger_ops = { .owner = THIS_MODULE, .set_trigger_state = &at91_adc_configure_trigger, }; static struct iio_trigger *at91_adc_allocate_trigger(struct iio_dev *idev, struct at91_adc_trigger *trigger) { struct iio_trigger *trig; int ret; trig = iio_trigger_alloc("%s-dev%d-%s", idev->name, idev->id, trigger->name); if (trig == NULL) return NULL; trig->dev.parent = idev->dev.parent; iio_trigger_set_drvdata(trig, idev); trig->ops = &at91_adc_trigger_ops; ret = iio_trigger_register(trig); if (ret) return NULL; return trig; } static int at91_adc_trigger_init(struct iio_dev *idev) { struct at91_adc_state *st = iio_priv(idev); int i, ret; st->trig = devm_kzalloc(&idev->dev, st->trigger_number * sizeof(st->trig), GFP_KERNEL); if (st->trig == NULL) { ret = -ENOMEM; goto error_ret; } for (i = 0; i < st->trigger_number; i++) { if (st->trigger_list[i].is_external && !(st->use_external)) continue; st->trig[i] = at91_adc_allocate_trigger(idev, st->trigger_list + i); if (st->trig[i] == NULL) { dev_err(&idev->dev, "Could not allocate trigger %d\n", i); ret = -ENOMEM; goto error_trigger; } } return 0; error_trigger: for (i--; i >= 0; i--) { iio_trigger_unregister(st->trig[i]); iio_trigger_free(st->trig[i]); } error_ret: return ret; } static void at91_adc_trigger_remove(struct iio_dev *idev) { struct at91_adc_state *st = iio_priv(idev); int i; for (i = 0; i < st->trigger_number; i++) { iio_trigger_unregister(st->trig[i]); iio_trigger_free(st->trig[i]); } } static int at91_adc_buffer_init(struct iio_dev *idev) { return iio_triggered_buffer_setup(idev, &iio_pollfunc_store_time, &at91_adc_trigger_handler, NULL); } static void at91_adc_buffer_remove(struct iio_dev *idev) { iio_triggered_buffer_cleanup(idev); } static int at91_adc_read_raw(struct iio_dev *idev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct at91_adc_state *st = iio_priv(idev); int ret; switch (mask) { case IIO_CHAN_INFO_RAW: mutex_lock(&st->lock); at91_adc_writel(st, AT91_ADC_CHER, AT91_ADC_CH(chan->channel)); at91_adc_writel(st, AT91_ADC_IER, st->registers->drdy_mask); at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_START); ret = wait_event_interruptible_timeout(st->wq_data_avail, st->done, msecs_to_jiffies(1000)); if (ret == 0) ret = -ETIMEDOUT; if (ret < 0) { mutex_unlock(&st->lock); return ret; } *val = st->last_value; at91_adc_writel(st, AT91_ADC_CHDR, AT91_ADC_CH(chan->channel)); at91_adc_writel(st, AT91_ADC_IDR, st->registers->drdy_mask); st->last_value = 0; st->done = false; mutex_unlock(&st->lock); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = (st->vref_mv * 1000) >> chan->scan_type.realbits; *val2 = 0; return IIO_VAL_INT_PLUS_MICRO; default: break; } return -EINVAL; } static int at91_adc_of_get_resolution(struct at91_adc_state *st, struct platform_device *pdev) { struct iio_dev *idev = iio_priv_to_dev(st); struct device_node *np = pdev->dev.of_node; int count, i, ret = 0; char *res_name, *s; u32 *resolutions; count = of_property_count_strings(np, "atmel,adc-res-names"); if (count < 2) { dev_err(&idev->dev, "You must specified at least two resolution names for " "adc-res-names property in the DT\n"); return count; } resolutions = kmalloc(count * sizeof(*resolutions), GFP_KERNEL); if (!resolutions) return -ENOMEM; if (of_property_read_u32_array(np, "atmel,adc-res", resolutions, count)) { dev_err(&idev->dev, "Missing adc-res property in the DT.\n"); ret = -ENODEV; goto ret; } if (of_property_read_string(np, "atmel,adc-use-res", (const char **)&res_name)) res_name = "highres"; for (i = 0; i < count; i++) { if (of_property_read_string_index(np, "atmel,adc-res-names", i, (const char **)&s)) continue; if (strcmp(res_name, s)) continue; st->res = resolutions[i]; if (!strcmp(res_name, "lowres")) st->low_res = true; else st->low_res = false; dev_info(&idev->dev, "Resolution used: %u bits\n", st->res); goto ret; } dev_err(&idev->dev, "There is no resolution for %s\n", res_name); ret: kfree(resolutions); return ret; } static int at91_adc_probe_dt(struct at91_adc_state *st, struct platform_device *pdev) { struct iio_dev *idev = iio_priv_to_dev(st); struct device_node *node = pdev->dev.of_node; struct device_node *trig_node; int i = 0, ret; u32 prop; if (!node) return -EINVAL; st->use_external = of_property_read_bool(node, "atmel,adc-use-external-triggers"); if (of_property_read_u32(node, "atmel,adc-channels-used", &prop)) { dev_err(&idev->dev, "Missing adc-channels-used property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->channels_mask = prop; if (of_property_read_u32(node, "atmel,adc-num-channels", &prop)) { dev_err(&idev->dev, "Missing adc-num-channels property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->num_channels = prop; st->sleep_mode = of_property_read_bool(node, "atmel,adc-sleep-mode"); if (of_property_read_u32(node, "atmel,adc-startup-time", &prop)) { dev_err(&idev->dev, "Missing adc-startup-time property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->startup_time = prop; prop = 0; of_property_read_u32(node, "atmel,adc-sample-hold-time", &prop); st->sample_hold_time = prop; if (of_property_read_u32(node, "atmel,adc-vref", &prop)) { dev_err(&idev->dev, "Missing adc-vref property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->vref_mv = prop; ret = at91_adc_of_get_resolution(st, pdev); if (ret) goto error_ret; st->registers = devm_kzalloc(&idev->dev, sizeof(struct at91_adc_reg_desc), GFP_KERNEL); if (!st->registers) { dev_err(&idev->dev, "Could not allocate register memory.\n"); ret = -ENOMEM; goto error_ret; } if (of_property_read_u32(node, "atmel,adc-channel-base", &prop)) { dev_err(&idev->dev, "Missing adc-channel-base property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->registers->channel_base = prop; if (of_property_read_u32(node, "atmel,adc-drdy-mask", &prop)) { dev_err(&idev->dev, "Missing adc-drdy-mask property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->registers->drdy_mask = prop; if (of_property_read_u32(node, "atmel,adc-status-register", &prop)) { dev_err(&idev->dev, "Missing adc-status-register property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->registers->status_register = prop; if (of_property_read_u32(node, "atmel,adc-trigger-register", &prop)) { dev_err(&idev->dev, "Missing adc-trigger-register property in the DT.\n"); ret = -EINVAL; goto error_ret; } st->registers->trigger_register = prop; st->trigger_number = of_get_child_count(node); st->trigger_list = devm_kzalloc(&idev->dev, st->trigger_number * sizeof(struct at91_adc_trigger), GFP_KERNEL); if (!st->trigger_list) { dev_err(&idev->dev, "Could not allocate trigger list memory.\n"); ret = -ENOMEM; goto error_ret; } for_each_child_of_node(node, trig_node) { struct at91_adc_trigger *trig = st->trigger_list + i; const char *name; if (of_property_read_string(trig_node, "trigger-name", &name)) { dev_err(&idev->dev, "Missing trigger-name property in the DT.\n"); ret = -EINVAL; goto error_ret; } trig->name = name; if (of_property_read_u32(trig_node, "trigger-value", &prop)) { dev_err(&idev->dev, "Missing trigger-value property in the DT.\n"); ret = -EINVAL; goto error_ret; } trig->value = prop; trig->is_external = of_property_read_bool(trig_node, "trigger-external"); i++; } return 0; error_ret: return ret; } static int at91_adc_probe_pdata(struct at91_adc_state *st, struct platform_device *pdev) { struct at91_adc_data *pdata = pdev->dev.platform_data; if (!pdata) return -EINVAL; st->use_external = pdata->use_external_triggers; st->vref_mv = pdata->vref; st->channels_mask = pdata->channels_used; st->num_channels = pdata->num_channels; st->startup_time = pdata->startup_time; st->trigger_number = pdata->trigger_number; st->trigger_list = pdata->trigger_list; st->registers = pdata->registers; return 0; } static const struct iio_info at91_adc_info = { .driver_module = THIS_MODULE, .read_raw = &at91_adc_read_raw, }; static int at91_adc_probe(struct platform_device *pdev) { unsigned int prsc, mstrclk, ticks, adc_clk, shtim; int ret; struct iio_dev *idev; struct at91_adc_state *st; struct resource *res; u32 reg; idev = devm_iio_device_alloc(&pdev->dev, sizeof(struct at91_adc_state)); if (!idev) return -ENOMEM; st = iio_priv(idev); if (pdev->dev.of_node) ret = at91_adc_probe_dt(st, pdev); else ret = at91_adc_probe_pdata(st, pdev); if (ret) { dev_err(&pdev->dev, "No platform data available.\n"); return -EINVAL; } platform_set_drvdata(pdev, idev); idev->dev.parent = &pdev->dev; idev->name = dev_name(&pdev->dev); idev->modes = INDIO_DIRECT_MODE; idev->info = &at91_adc_info; st->irq = platform_get_irq(pdev, 0); if (st->irq < 0) { dev_err(&pdev->dev, "No IRQ ID is designated\n"); return -ENODEV; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); st->reg_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(st->reg_base)) { return PTR_ERR(st->reg_base); } /* * Disable all IRQs before setting up the handler */ at91_adc_writel(st, AT91_ADC_CR, AT91_ADC_SWRST); at91_adc_writel(st, AT91_ADC_IDR, 0xFFFFFFFF); ret = request_irq(st->irq, at91_adc_eoc_trigger, 0, pdev->dev.driver->name, idev); if (ret) { dev_err(&pdev->dev, "Failed to allocate IRQ.\n"); return ret; } st->clk = devm_clk_get(&pdev->dev, "adc_clk"); if (IS_ERR(st->clk)) { dev_err(&pdev->dev, "Failed to get the clock.\n"); ret = PTR_ERR(st->clk); goto error_free_irq; } ret = clk_prepare_enable(st->clk); if (ret) { dev_err(&pdev->dev, "Could not prepare or enable the clock.\n"); goto error_free_irq; } st->adc_clk = devm_clk_get(&pdev->dev, "adc_op_clk"); if (IS_ERR(st->adc_clk)) { dev_err(&pdev->dev, "Failed to get the ADC clock.\n"); ret = PTR_ERR(st->adc_clk); goto error_disable_clk; } ret = clk_prepare_enable(st->adc_clk); if (ret) { dev_err(&pdev->dev, "Could not prepare or enable the ADC clock.\n"); goto error_disable_clk; } /* * Prescaler rate computation using the formula from the Atmel's * datasheet : ADC Clock = MCK / ((Prescaler + 1) * 2), ADC Clock being * specified by the electrical characteristics of the board. */ mstrclk = clk_get_rate(st->clk); adc_clk = clk_get_rate(st->adc_clk); prsc = (mstrclk / (2 * adc_clk)) - 1; if (!st->startup_time) { dev_err(&pdev->dev, "No startup time available.\n"); ret = -EINVAL; goto error_disable_adc_clk; } /* * Number of ticks needed to cover the startup time of the ADC as * defined in the electrical characteristics of the board, divided by 8. * The formula thus is : Startup Time = (ticks + 1) * 8 / ADC Clock */ ticks = round_up((st->startup_time * adc_clk / 1000000) - 1, 8) / 8; /* * a minimal Sample and Hold Time is necessary for the ADC to guarantee * the best converted final value between two channels selection * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock */ shtim = round_up((st->sample_hold_time * adc_clk / 1000000) - 1, 1); reg = AT91_ADC_PRESCAL_(prsc) & AT91_ADC_PRESCAL; reg |= AT91_ADC_STARTUP_(ticks) & AT91_ADC_STARTUP; if (st->low_res) reg |= AT91_ADC_LOWRES; if (st->sleep_mode) reg |= AT91_ADC_SLEEP; reg |= AT91_ADC_SHTIM_(shtim) & AT91_ADC_SHTIM; at91_adc_writel(st, AT91_ADC_MR, reg); /* Setup the ADC channels available on the board */ ret = at91_adc_channel_init(idev); if (ret < 0) { dev_err(&pdev->dev, "Couldn't initialize the channels.\n"); goto error_disable_adc_clk; } init_waitqueue_head(&st->wq_data_avail); mutex_init(&st->lock); ret = at91_adc_buffer_init(idev); if (ret < 0) { dev_err(&pdev->dev, "Couldn't initialize the buffer.\n"); goto error_disable_adc_clk; } ret = at91_adc_trigger_init(idev); if (ret < 0) { dev_err(&pdev->dev, "Couldn't setup the triggers.\n"); goto error_unregister_buffer; } ret = iio_device_register(idev); if (ret < 0) { dev_err(&pdev->dev, "Couldn't register the device.\n"); goto error_remove_triggers; } return 0; error_remove_triggers: at91_adc_trigger_remove(idev); error_unregister_buffer: at91_adc_buffer_remove(idev); error_disable_adc_clk: clk_disable_unprepare(st->adc_clk); error_disable_clk: clk_disable_unprepare(st->clk); error_free_irq: free_irq(st->irq, idev); return ret; } static int at91_adc_remove(struct platform_device *pdev) { struct iio_dev *idev = platform_get_drvdata(pdev); struct at91_adc_state *st = iio_priv(idev); iio_device_unregister(idev); at91_adc_trigger_remove(idev); at91_adc_buffer_remove(idev); clk_disable_unprepare(st->adc_clk); clk_disable_unprepare(st->clk); free_irq(st->irq, idev); return 0; } #ifdef CONFIG_OF static const struct of_device_id at91_adc_dt_ids[] = { { .compatible = "atmel,at91sam9260-adc" }, {}, }; MODULE_DEVICE_TABLE(of, at91_adc_dt_ids); #endif static struct platform_driver at91_adc_driver = { .probe = at91_adc_probe, .remove = at91_adc_remove, .driver = { .name = "at91_adc", .of_match_table = of_match_ptr(at91_adc_dt_ids), }, }; module_platform_driver(at91_adc_driver); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Atmel AT91 ADC Driver"); MODULE_AUTHOR("Maxime Ripard ");