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Subject[PATCH v2 3/3] IIO: Ingenic JZ47xx: Add support for JZ4770 SoC ADC.
Date
Add support for the ADC hardware present on Ingenic JZ4770 SoC.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
---

Changes:

v2: - move the IIO_CHAN_INFO_RAW block into a utility function,
- unconditionally lock aux_lock for reduced complexity

drivers/iio/adc/ingenic-adc.c | 149 +++++++++++++++++++++++++++++-----
1 file changed, 127 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
index e234970b7150..7a53c2f8d438 100644
--- a/drivers/iio/adc/ingenic-adc.c
+++ b/drivers/iio/adc/ingenic-adc.c
@@ -25,9 +25,13 @@
#define JZ_ADC_REG_ADSDAT 0x20
#define JZ_ADC_REG_ADCLK 0x28

+#define JZ_ADC_REG_ENABLE_PD BIT(7)
+#define JZ_ADC_REG_CFG_AUX_MD (BIT(0) | BIT(1))
#define JZ_ADC_REG_CFG_BAT_MD BIT(4)
#define JZ_ADC_REG_ADCLK_CLKDIV_LSB 0
-#define JZ_ADC_REG_ADCLK_CLKDIV10US_LSB 16
+#define JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB 16
+#define JZ4770_ADC_REG_ADCLK_CLKDIV10US_LSB 8
+#define JZ4770_ADC_REG_ADCLK_CLKDIVMS_LSB 16

#define JZ_ADC_AUX_VREF 3300
#define JZ_ADC_AUX_VREF_BITS 12
@@ -37,6 +41,8 @@
#define JZ4725B_ADC_BATTERY_HIGH_VREF_BITS 10
#define JZ4740_ADC_BATTERY_HIGH_VREF (7500 * 0.986)
#define JZ4740_ADC_BATTERY_HIGH_VREF_BITS 12
+#define JZ4770_ADC_BATTERY_VREF 6600
+#define JZ4770_ADC_BATTERY_VREF_BITS 12

struct ingenic_adc;

@@ -47,6 +53,8 @@ struct ingenic_adc_soc_data {
size_t battery_raw_avail_size;
const int *battery_scale_avail;
size_t battery_scale_avail_size;
+ unsigned int battery_vref_mode: 1;
+ unsigned int has_aux2: 1;
int (*init_clk_div)(struct device *dev, struct ingenic_adc *adc);
};

@@ -54,6 +62,7 @@ struct ingenic_adc {
void __iomem *base;
struct clk *clk;
struct mutex lock;
+ struct mutex aux_lock;
const struct ingenic_adc_soc_data *soc_data;
bool low_vref_mode;
};
@@ -120,6 +129,8 @@ static int ingenic_adc_write_raw(struct iio_dev *iio_dev,
case IIO_CHAN_INFO_SCALE:
switch (chan->channel) {
case INGENIC_ADC_BATTERY:
+ if (!adc->soc_data->battery_vref_mode)
+ return -EINVAL;
if (val > JZ_ADC_BATTERY_LOW_VREF) {
ingenic_adc_set_config(adc,
JZ_ADC_REG_CFG_BAT_MD,
@@ -158,6 +169,14 @@ static const int jz4740_adc_battery_scale_avail[] = {
JZ_ADC_BATTERY_LOW_VREF, JZ_ADC_BATTERY_LOW_VREF_BITS,
};

+static const int jz4770_adc_battery_raw_avail[] = {
+ 0, 1, (1 << JZ4770_ADC_BATTERY_VREF_BITS) - 1,
+};
+
+static const int jz4770_adc_battery_scale_avail[] = {
+ JZ4770_ADC_BATTERY_VREF, JZ4770_ADC_BATTERY_VREF_BITS,
+};
+
static int jz4725b_adc_init_clk_div(struct device *dev, struct ingenic_adc *adc)
{
struct clk *parent_clk;
@@ -187,7 +206,45 @@ static int jz4725b_adc_init_clk_div(struct device *dev, struct ingenic_adc *adc)
/* We also need a divider that produces a 10us clock. */
div_10us = DIV_ROUND_UP(rate, 100000);

- writel(((div_10us - 1) << JZ_ADC_REG_ADCLK_CLKDIV10US_LSB) |
+ writel(((div_10us - 1) << JZ4725B_ADC_REG_ADCLK_CLKDIV10US_LSB) |
+ (div_main - 1) << JZ_ADC_REG_ADCLK_CLKDIV_LSB,
+ adc->base + JZ_ADC_REG_ADCLK);
+
+ return 0;
+}
+
+static int jz4770_adc_init_clk_div(struct device *dev, struct ingenic_adc *adc)
+{
+ struct clk *parent_clk;
+ unsigned long parent_rate, rate;
+ unsigned int div_main, div_ms, div_10us;
+
+ parent_clk = clk_get_parent(adc->clk);
+ if (!parent_clk) {
+ dev_err(dev, "ADC clock has no parent\n");
+ return -ENODEV;
+ }
+ parent_rate = clk_get_rate(parent_clk);
+
+ /*
+ * The JZ4770 ADC works at 20 kHz to 200 kHz.
+ * We pick the highest rate possible.
+ */
+ div_main = DIV_ROUND_UP(parent_rate, 200000);
+ div_main = clamp(div_main, 1u, 256u);
+ rate = parent_rate / div_main;
+ if (rate < 20000 || rate > 200000) {
+ dev_err(dev, "No valid divider for ADC main clock\n");
+ return -EINVAL;
+ }
+
+ /* We also need a divider that produces a 10us clock. */
+ div_10us = DIV_ROUND_UP(rate, 10000);
+ /* And another, which produces a 1ms clock. */
+ div_ms = DIV_ROUND_UP(rate, 1000);
+
+ writel(((div_ms - 1) << JZ4770_ADC_REG_ADCLK_CLKDIVMS_LSB) |
+ ((div_10us - 1) << JZ4770_ADC_REG_ADCLK_CLKDIV10US_LSB) |
(div_main - 1) << JZ_ADC_REG_ADCLK_CLKDIV_LSB,
adc->base + JZ_ADC_REG_ADCLK);

@@ -201,6 +258,8 @@ static const struct ingenic_adc_soc_data jz4725b_adc_soc_data = {
.battery_raw_avail_size = ARRAY_SIZE(jz4725b_adc_battery_raw_avail),
.battery_scale_avail = jz4725b_adc_battery_scale_avail,
.battery_scale_avail_size = ARRAY_SIZE(jz4725b_adc_battery_scale_avail),
+ .battery_vref_mode = true,
+ .has_aux2 = false,
.init_clk_div = jz4725b_adc_init_clk_div,
};

@@ -211,9 +270,23 @@ static const struct ingenic_adc_soc_data jz4740_adc_soc_data = {
.battery_raw_avail_size = ARRAY_SIZE(jz4740_adc_battery_raw_avail),
.battery_scale_avail = jz4740_adc_battery_scale_avail,
.battery_scale_avail_size = ARRAY_SIZE(jz4740_adc_battery_scale_avail),
+ .battery_vref_mode = true,
+ .has_aux2 = false,
.init_clk_div = NULL, /* no ADCLK register on JZ4740 */
};

+static const struct ingenic_adc_soc_data jz4770_adc_soc_data = {
+ .battery_high_vref = JZ4770_ADC_BATTERY_VREF,
+ .battery_high_vref_bits = JZ4770_ADC_BATTERY_VREF_BITS,
+ .battery_raw_avail = jz4770_adc_battery_raw_avail,
+ .battery_raw_avail_size = ARRAY_SIZE(jz4770_adc_battery_raw_avail),
+ .battery_scale_avail = jz4770_adc_battery_scale_avail,
+ .battery_scale_avail_size = ARRAY_SIZE(jz4770_adc_battery_scale_avail),
+ .battery_vref_mode = false,
+ .has_aux2 = true,
+ .init_clk_div = jz4770_adc_init_clk_div,
+};
+
static int ingenic_adc_read_avail(struct iio_dev *iio_dev,
struct iio_chan_spec const *chan,
const int **vals,
@@ -239,6 +312,42 @@ static int ingenic_adc_read_avail(struct iio_dev *iio_dev,
};
}

+static int ingenic_adc_read_chan_info_raw(struct ingenic_adc *adc,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ int bit, ret, engine = (chan->channel == INGENIC_ADC_BATTERY);
+
+ /* We cannot sample AUX/AUX2 in parallel. */
+ mutex_lock(&adc->aux_lock);
+ if (adc->soc_data->has_aux2 && engine == 0) {
+ bit = BIT(chan->channel == INGENIC_ADC_AUX2);
+ ingenic_adc_set_config(adc, JZ_ADC_REG_CFG_AUX_MD, bit);
+ }
+
+ clk_enable(adc->clk);
+ ret = ingenic_adc_capture(adc, engine);
+ if (ret)
+ goto out;
+
+ switch (chan->channel) {
+ case INGENIC_ADC_AUX:
+ case INGENIC_ADC_AUX2:
+ *val = readw(adc->base + JZ_ADC_REG_ADSDAT);
+ break;
+ case INGENIC_ADC_BATTERY:
+ *val = readw(adc->base + JZ_ADC_REG_ADBDAT);
+ break;
+ }
+
+ ret = IIO_VAL_INT;
+out:
+ clk_disable(adc->clk);
+ mutex_unlock(&adc->aux_lock);
+
+ return ret;
+}
+
static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
struct iio_chan_spec const *chan,
int *val,
@@ -246,32 +355,14 @@ static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
long m)
{
struct ingenic_adc *adc = iio_priv(iio_dev);
- int ret;

switch (m) {
case IIO_CHAN_INFO_RAW:
- clk_enable(adc->clk);
- ret = ingenic_adc_capture(adc, chan->channel);
- if (ret) {
- clk_disable(adc->clk);
- return ret;
- }
-
- switch (chan->channel) {
- case INGENIC_ADC_AUX:
- *val = readw(adc->base + JZ_ADC_REG_ADSDAT);
- break;
- case INGENIC_ADC_BATTERY:
- *val = readw(adc->base + JZ_ADC_REG_ADBDAT);
- break;
- }
-
- clk_disable(adc->clk);
-
- return IIO_VAL_INT;
+ return ingenic_adc_read_chan_info_raw(adc, chan, val);
case IIO_CHAN_INFO_SCALE:
switch (chan->channel) {
case INGENIC_ADC_AUX:
+ case INGENIC_ADC_AUX2:
*val = JZ_ADC_AUX_VREF;
*val2 = JZ_ADC_AUX_VREF_BITS;
break;
@@ -322,6 +413,14 @@ static const struct iio_chan_spec ingenic_channels[] = {
.indexed = 1,
.channel = INGENIC_ADC_BATTERY,
},
+ { /* Must always be last in the array. */
+ .extend_name = "aux2",
+ .type = IIO_VOLTAGE,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .indexed = 1,
+ .channel = INGENIC_ADC_AUX2,
+ },
};

static int ingenic_adc_probe(struct platform_device *pdev)
@@ -343,6 +442,7 @@ static int ingenic_adc_probe(struct platform_device *pdev)

adc = iio_priv(iio_dev);
mutex_init(&adc->lock);
+ mutex_init(&adc->aux_lock);
adc->soc_data = soc_data;

mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -374,6 +474,7 @@ static int ingenic_adc_probe(struct platform_device *pdev)
/* Put hardware in a known passive state. */
writeb(0x00, adc->base + JZ_ADC_REG_ENABLE);
writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
+ usleep_range(2000, 3000); /* Must wait at least 2ms. */
clk_disable(adc->clk);

ret = devm_add_action_or_reset(dev, ingenic_adc_clk_cleanup, adc->clk);
@@ -387,6 +488,9 @@ static int ingenic_adc_probe(struct platform_device *pdev)
iio_dev->modes = INDIO_DIRECT_MODE;
iio_dev->channels = ingenic_channels;
iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
+ /* Remove AUX2 from the list of supported channels. */
+ if (!adc->soc_data->has_aux2)
+ iio_dev->num_channels -= 1;
iio_dev->info = &ingenic_adc_info;

ret = devm_iio_device_register(dev, iio_dev);
@@ -400,6 +504,7 @@ static int ingenic_adc_probe(struct platform_device *pdev)
static const struct of_device_id ingenic_adc_of_match[] = {
{ .compatible = "ingenic,jz4725b-adc", .data = &jz4725b_adc_soc_data, },
{ .compatible = "ingenic,jz4740-adc", .data = &jz4740_adc_soc_data, },
+ { .compatible = "ingenic,jz4770-adc", .data = &jz4770_adc_soc_data, },
{ },
};
MODULE_DEVICE_TABLE(of, ingenic_adc_of_match);
--
2.22.0
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