iio: ti_am335x_adc: Allow to specify input line

The TSC part allows to specify the input lines. The IIO part assumes that it usues always the last few, that means if IIO has adc-channels set to 2 it will use channel 6 and 7. However it might make sense to use only 6. This patch changes the device property (which was introduced recently and was never in an official release) in a way that the user can specify which of the AIN lines should be used. In Addition to this, the name is now AINx where x is the channel number i.e. for AIN6 we would have 6. Prior this, it always started counting at 0 which is confusing. In addition to this, it also checks for correct step number during reading and does not rely on proper FIFO depth. Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

iio: ti_am335x_adc: Allow to specify input line
The TSC part allows to specify the input lines. The IIO part assumes that it usues always the last few, that means if IIO has adc-channels set to 2 it will use channel 6 and 7. However it might make sense to use only 6. This patch changes the device property (which was introduced recently and was never in an official release) in a way that the user can specify which of the AIN lines should be used. In Addition to this, the name is now AINx where x is the channel number i.e. for AIN6 we would have 6. Prior this, it always started counting at 0 which is confusing. In addition to this, it also checks for correct step number during reading and does not rely on proper FIFO depth. Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Sebastian Andrzej Siewior
1 parent 9a28b8834c
Showing 3 changed files with 56 additions and 23 deletions Side-by-side Diff
arch/arm/boot/dts/am335x-evm.dts
drivers/iio/adc/ti_am335x_adc.c
drivers/mfd/ti_am335x_tscadc.c
@@ -255,7 +255,7 @@
 	};
  
 	adc {
-		ti,adc-channels = <4>;
+		ti,adc-channels = <4 5 6 7>;
 	};
 };
@@ -32,6 +32,8 @@
 struct tiadc_device {
 	struct ti_tscadc_dev *mfd_tscadc;
 	int channels;
+	u8 channel_line[8];
+	u8 channel_step[8];
 };
  
 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
@@ -57,7 +59,7 @@
 static void tiadc_step_config(struct tiadc_device *adc_dev)
 {
 	unsigned int stepconfig;
-	int i, channels = 0, steps;
+	int i, steps;
 	u32 step_en;
  
 	/*
  
  
@@ -71,16 +73,18 @@
 	 */
  
 	steps = TOTAL_STEPS - adc_dev->channels;
-	channels = TOTAL_CHANNELS - adc_dev->channels;
-
 	stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
  
-	for (i = steps; i < TOTAL_STEPS; i++) {
-		tiadc_writel(adc_dev, REG_STEPCONFIG(i),
-				stepconfig | STEPCONFIG_INP(channels));
-		tiadc_writel(adc_dev, REG_STEPDELAY(i),
+	for (i = 0; i < adc_dev->channels; i++) {
+		int chan;
+
+		chan = adc_dev->channel_line[i];
+		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
+				stepconfig | STEPCONFIG_INP(chan));
+		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
 				STEPCONFIG_OPENDLY);
-		channels++;
+		adc_dev->channel_step[i] = steps;
+		steps++;
 	}
 	step_en = get_adc_step_mask(adc_dev);
 	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
  
@@ -115,9 +119,9 @@
  
 		chan->type = IIO_VOLTAGE;
 		chan->indexed = 1;
-		chan->channel = i;
+		chan->channel = adc_dev->channel_line[i];
 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
-		chan->datasheet_name = chan_name_ain[i];
+		chan->datasheet_name = chan_name_ain[chan->channel];
 		chan->scan_type.sign = 'u';
 		chan->scan_type.realbits = 12;
 		chan->scan_type.storagebits = 32;
@@ -139,7 +143,8 @@
 {
 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
 	int i;
-	unsigned int fifo1count, readx1;
+	unsigned int fifo1count, read;
+	u32 step = UINT_MAX;
  
 	/*
 	 * When the sub-system is first enabled,
  
@@ -152,11 +157,20 @@
 	 * Hence we need to flush out this data.
 	 */
  
+	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
+		if (chan->channel == adc_dev->channel_line[i]) {
+			step = adc_dev->channel_step[i];
+			break;
+		}
+	}
+	if (WARN_ON_ONCE(step == UINT_MAX))
+		return -EINVAL;
+
 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
 	for (i = 0; i < fifo1count; i++) {
-		readx1 = tiadc_readl(adc_dev, REG_FIFO1);
-		if (i == chan->channel)
-			*val = readx1 & 0xfff;
+		read = tiadc_readl(adc_dev, REG_FIFO1);
+		if (read >> 16 == step)
+			*val = read & 0xfff;
 	}
 	am335x_tsc_se_update(adc_dev->mfd_tscadc);
  
  
@@ -172,8 +186,11 @@
 	struct iio_dev		*indio_dev;
 	struct tiadc_device	*adc_dev;
 	struct device_node	*node = pdev->dev.of_node;
+	struct property		*prop;
+	const __be32		*cur;
 	int			err;
-	u32			val32;
+	u32			val;
+	int			channels = 0;
  
 	if (!node) {
 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
@@ -190,11 +207,11 @@
  
 	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
  
-	err = of_property_read_u32(node,
-			"ti,adc-channels", &val32);
-	if (err < 0)
-		goto err_free_device;
-	adc_dev->channels = val32;
+	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
+		adc_dev->channel_line[channels] = val;
+		channels++;
+	}
+	adc_dev->channels = channels;
  
 	indio_dev->dev.parent = &pdev->dev;
 	indio_dev->name = dev_name(&pdev->dev);
@@ -91,9 +91,13 @@
 	struct clk		*clk;
 	struct device_node	*node = pdev->dev.of_node;
 	struct mfd_cell		*cell;
+	struct property         *prop;
+	const __be32            *cur;
+	u32			val;
 	int			err, ctrl;
 	int			clk_value, clock_rate;
 	int			tsc_wires = 0, adc_channels = 0, total_channels;
+	int			readouts = 0;
  
 	if (!pdev->dev.of_node) {
 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
  
@@ -102,10 +106,17 @@
  
 	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 	of_property_read_u32(node, "ti,wires", &tsc_wires);
+	of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
  
 	node = of_get_child_by_name(pdev->dev.of_node, "adc");
-	of_property_read_u32(node, "ti,adc-channels", &adc_channels);
-
+	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
+		adc_channels++;
+		if (val > 7) {
+			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
+					val);
+			return -EINVAL;
+		}
+	}
 	total_channels = tsc_wires + adc_channels;
 	if (total_channels > 8) {
 		dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
@@ -113,6 +124,11 @@
 	}
 	if (total_channels == 0) {
 		dev_err(&pdev->dev, "Need atleast one channel.\n");
+		return -EINVAL;
+	}
+
+	if (readouts * 2 + 2 + adc_channels > 16) {
+		dev_err(&pdev->dev, "Too many step configurations requested\n");
 		return -EINVAL;
 	}
...	...	@@ -255,7 +255,7 @@
255	255	};
256	256
257	257	adc {
258		- ti,adc-channels = <4>;
	258	+ ti,adc-channels = <4 5 6 7>;
259	259	};
260	260	};
...	...	@@ -32,6 +32,8 @@
32	32	struct tiadc_device {
33	33	struct ti_tscadc_dev *mfd_tscadc;
34	34	int channels;
	35	+ u8 channel_line[8];
	36	+ u8 channel_step[8];
35	37	};
36	38
37	39	static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
...	...	@@ -57,7 +59,7 @@
57	59	static void tiadc_step_config(struct tiadc_device *adc_dev)
58	60	{
59	61	unsigned int stepconfig;
60		- int i, channels = 0, steps;
	62	+ int i, steps;
61	63	u32 step_en;
62	64
63	65	/*
64	66
65	67
...	...	@@ -71,16 +73,18 @@
71	73	*/
72	74
73	75	steps = TOTAL_STEPS - adc_dev->channels;
74		- channels = TOTAL_CHANNELS - adc_dev->channels;
75		-
76	76	stepconfig = STEPCONFIG_AVG_16 \| STEPCONFIG_FIFO1;
77	77
78		- for (i = steps; i < TOTAL_STEPS; i++) {
79		- tiadc_writel(adc_dev, REG_STEPCONFIG(i),
80		- stepconfig \| STEPCONFIG_INP(channels));
81		- tiadc_writel(adc_dev, REG_STEPDELAY(i),
	78	+ for (i = 0; i < adc_dev->channels; i++) {
	79	+ int chan;
	80	+
	81	+ chan = adc_dev->channel_line[i];
	82	+ tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
	83	+ stepconfig \| STEPCONFIG_INP(chan));
	84	+ tiadc_writel(adc_dev, REG_STEPDELAY(steps),
82	85	STEPCONFIG_OPENDLY);
83		- channels++;
	86	+ adc_dev->channel_step[i] = steps;
	87	+ steps++;
84	88	}
85	89	step_en = get_adc_step_mask(adc_dev);
86	90	am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
87	91
...	...	@@ -115,9 +119,9 @@
115	119
116	120	chan->type = IIO_VOLTAGE;
117	121	chan->indexed = 1;
118		- chan->channel = i;
	122	+ chan->channel = adc_dev->channel_line[i];
119	123	chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
120		- chan->datasheet_name = chan_name_ain[i];
	124	+ chan->datasheet_name = chan_name_ain[chan->channel];
121	125	chan->scan_type.sign = 'u';
122	126	chan->scan_type.realbits = 12;
123	127	chan->scan_type.storagebits = 32;
...	...	@@ -139,7 +143,8 @@
139	143	{
140	144	struct tiadc_device *adc_dev = iio_priv(indio_dev);
141	145	int i;
142		- unsigned int fifo1count, readx1;
	146	+ unsigned int fifo1count, read;
	147	+ u32 step = UINT_MAX;
143	148
144	149	/*
145	150	* When the sub-system is first enabled,
146	151
...	...	@@ -152,11 +157,20 @@
152	157	* Hence we need to flush out this data.
153	158	*/
154	159
	160	+ for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
	161	+ if (chan->channel == adc_dev->channel_line[i]) {
	162	+ step = adc_dev->channel_step[i];
	163	+ break;
	164	+ }
	165	+ }
	166	+ if (WARN_ON_ONCE(step == UINT_MAX))
	167	+ return -EINVAL;
	168	+
155	169	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
156	170	for (i = 0; i < fifo1count; i++) {
157		- readx1 = tiadc_readl(adc_dev, REG_FIFO1);
158		- if (i == chan->channel)
159		- *val = readx1 & 0xfff;
	171	+ read = tiadc_readl(adc_dev, REG_FIFO1);
	172	+ if (read >> 16 == step)
	173	+ *val = read & 0xfff;
160	174	}
161	175	am335x_tsc_se_update(adc_dev->mfd_tscadc);
162	176
163	177
...	...	@@ -172,8 +186,11 @@
172	186	struct iio_dev *indio_dev;
173	187	struct tiadc_device *adc_dev;
174	188	struct device_node *node = pdev->dev.of_node;
	189	+ struct property *prop;
	190	+ const __be32 *cur;
175	191	int err;
176		- u32 val32;
	192	+ u32 val;
	193	+ int channels = 0;
177	194
178	195	if (!node) {
179	196	dev_err(&pdev->dev, "Could not find valid DT data.\n");
...	...	@@ -190,11 +207,11 @@
190	207
191	208	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
192	209
193		- err = of_property_read_u32(node,
194		- "ti,adc-channels", &val32);
195		- if (err < 0)
196		- goto err_free_device;
197		- adc_dev->channels = val32;
	210	+ of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
	211	+ adc_dev->channel_line[channels] = val;
	212	+ channels++;
	213	+ }
	214	+ adc_dev->channels = channels;
198	215
199	216	indio_dev->dev.parent = &pdev->dev;
200	217	indio_dev->name = dev_name(&pdev->dev);
...	...	@@ -91,9 +91,13 @@
91	91	struct clk *clk;
92	92	struct device_node *node = pdev->dev.of_node;
93	93	struct mfd_cell *cell;
	94	+ struct property *prop;
	95	+ const __be32 *cur;
	96	+ u32 val;
94	97	int err, ctrl;
95	98	int clk_value, clock_rate;
96	99	int tsc_wires = 0, adc_channels = 0, total_channels;
	100	+ int readouts = 0;
97	101
98	102	if (!pdev->dev.of_node) {
99	103	dev_err(&pdev->dev, "Could not find valid DT data.\n");
100	104
...	...	@@ -102,10 +106,17 @@
102	106
103	107	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
104	108	of_property_read_u32(node, "ti,wires", &tsc_wires);
	109	+ of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
105	110
106	111	node = of_get_child_by_name(pdev->dev.of_node, "adc");
107		- of_property_read_u32(node, "ti,adc-channels", &adc_channels);
108		-
	112	+ of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
	113	+ adc_channels++;
	114	+ if (val > 7) {
	115	+ dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
	116	+ val);
	117	+ return -EINVAL;
	118	+ }
	119	+ }
109	120	total_channels = tsc_wires + adc_channels;
110	121	if (total_channels > 8) {
111	122	dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
...	...	@@ -113,6 +124,11 @@
113	124	}
114	125	if (total_channels == 0) {
115	126	dev_err(&pdev->dev, "Need atleast one channel.\n");
	127	+ return -EINVAL;
	128	+ }
	129	+
	130	+ if (readouts * 2 + 2 + adc_channels > 16) {
	131	+ dev_err(&pdev->dev, "Too many step configurations requested\n");
116	132	return -EINVAL;
117	133	}
118	134