2  * Driver for ADC module on the Cirrus Logic EP93xx series of SoCs
17 #include <linux/clk.h>
30  * lower ADC conversion rate down to CONFIG_HZ, so we fallback to busy wait
33  * HR Timers-based version loads CPU only up to 10% during back to back ADC
34  * conversion, while busy wait-based version consumes whole CPU power.
48 	struct clk *clk;  member
91 		mutex_lock(&priv->lock);  in ep93xx_read_raw()
92 		if (priv->lastch != channel->channel) {  in ep93xx_read_raw()
93 			priv->lastch = channel->channel;  in ep93xx_read_raw()
95 			 * Switch register is software-locked, unlocking must be  in ep93xx_read_raw()
99 			writel_relaxed(0xAA, priv->base + EP93XX_ADC_SW_LOCK);  in ep93xx_read_raw()
100 			writel_relaxed(channel->address,  in ep93xx_read_raw()
101 				       priv->base + EP93XX_ADC_SWITCH);  in ep93xx_read_raw()
110 		readl_relaxed(priv->base + EP93XX_ADC_RESULT);  in ep93xx_read_raw()
120 			t = readl_relaxed(priv->base + EP93XX_ADC_RESULT);  in ep93xx_read_raw()
127 				dev_err(&iiodev->dev, "Conversion timeout\n");  in ep93xx_read_raw()
128 				ret = -ETIMEDOUT;  in ep93xx_read_raw()
134 		mutex_unlock(&priv->lock);  in ep93xx_read_raw()
138 		/* According to datasheet, range is -25000..25000 */  in ep93xx_read_raw()
149 	return -EINVAL;  in ep93xx_read_raw()
161 	struct clk *pclk;  in ep93xx_adc_probe()
164 	iiodev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));  in ep93xx_adc_probe()
166 		return -ENOMEM;  in ep93xx_adc_probe()
170 	priv->base = devm_ioremap_resource(&pdev->dev, res);  in ep93xx_adc_probe()
171 	if (IS_ERR(priv->base)) {  in ep93xx_adc_probe()
172 		dev_err(&pdev->dev, "Cannot map memory resource\n");  in ep93xx_adc_probe()
173 		return PTR_ERR(priv->base);  in ep93xx_adc_probe()
176 	iiodev->dev.parent = &pdev->dev;  in ep93xx_adc_probe()
177 	iiodev->name = dev_name(&pdev->dev);  in ep93xx_adc_probe()
178 	iiodev->modes = INDIO_DIRECT_MODE;  in ep93xx_adc_probe()
179 	iiodev->info = &ep93xx_adc_info;  in ep93xx_adc_probe()
180 	iiodev->num_channels = ARRAY_SIZE(ep93xx_adc_channels);  in ep93xx_adc_probe()
181 	iiodev->channels = ep93xx_adc_channels;  in ep93xx_adc_probe()
183 	priv->lastch = -1;  in ep93xx_adc_probe()
184 	mutex_init(&priv->lock);  in ep93xx_adc_probe()
188 	priv->clk = devm_clk_get(&pdev->dev, NULL);  in ep93xx_adc_probe()
189 	if (IS_ERR(priv->clk)) {  in ep93xx_adc_probe()
190 		dev_err(&pdev->dev, "Cannot obtain clock\n");  in ep93xx_adc_probe()
191 		return PTR_ERR(priv->clk);  in ep93xx_adc_probe()
194 	pclk = clk_get_parent(priv->clk);  in ep93xx_adc_probe()
196 		dev_warn(&pdev->dev, "Cannot obtain parent clock\n");  in ep93xx_adc_probe()
200 		 * EP93xx ADC supports two clock divisors -- 4 and 16,  in ep93xx_adc_probe()
205 		ret = clk_set_rate(priv->clk, clk_get_rate(pclk) / 16);  in ep93xx_adc_probe()
207 			dev_warn(&pdev->dev, "Cannot set clock rate\n");  in ep93xx_adc_probe()
214 	ret = clk_enable(priv->clk);  in ep93xx_adc_probe()
216 		dev_err(&pdev->dev, "Cannot enable clock\n");  in ep93xx_adc_probe()
222 		clk_disable(priv->clk);  in ep93xx_adc_probe()
233 	clk_disable(priv->clk);  in ep93xx_adc_remove()
240 		.name = "ep93xx-adc",
248 MODULE_DESCRIPTION("Cirrus Logic EP93XX ADC driver");
250 MODULE_ALIAS("platform:ep93xx-adc");