fsl-imx25-tsadc.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
  4 */
  5
  6#include <linux/clk.h>
  7#include <linux/interrupt.h>
  8#include <linux/irqchip/chained_irq.h>
  9#include <linux/irqdesc.h>
 10#include <linux/irqdomain.h>
 11#include <linux/irq.h>
 12#include <linux/mfd/imx25-tsadc.h>
 13#include <linux/module.h>
 14#include <linux/of.h>
 15#include <linux/of_platform.h>
 16#include <linux/platform_device.h>
 17#include <linux/regmap.h>
 18
 19static const struct regmap_config mx25_tsadc_regmap_config = {
 20	.max_register = 8,
 21	.reg_bits = 32,
 22	.val_bits = 32,
 23	.reg_stride = 4,
 24};
 25
 26static void mx25_tsadc_irq_handler(struct irq_desc *desc)
 27{
 28	struct mx25_tsadc *tsadc = irq_desc_get_handler_data(desc);
 29	struct irq_chip *chip = irq_desc_get_chip(desc);
 30	u32 status;
 31
 32	chained_irq_enter(chip, desc);
 33
 34	regmap_read(tsadc->regs, MX25_TSC_TGSR, &status);
 35
 36	if (status & MX25_TGSR_GCQ_INT)
 37		generic_handle_domain_irq(tsadc->domain, 1);
 38
 39	if (status & MX25_TGSR_TCQ_INT)
 40		generic_handle_domain_irq(tsadc->domain, 0);
 41
 42	chained_irq_exit(chip, desc);
 43}
 44
 45static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq,
 46				 irq_hw_number_t hwirq)
 47{
 48	struct mx25_tsadc *tsadc = d->host_data;
 49
 50	irq_set_chip_data(irq, tsadc);
 51	irq_set_chip_and_handler(irq, &dummy_irq_chip,
 52				 handle_level_irq);
 53	irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);
 54
 55	return 0;
 56}
 57
 58static const struct irq_domain_ops mx25_tsadc_domain_ops = {
 59	.map = mx25_tsadc_domain_map,
 60	.xlate = irq_domain_xlate_onecell,
 61};
 62
 63static int mx25_tsadc_setup_irq(struct platform_device *pdev,
 64				struct mx25_tsadc *tsadc)
 65{
 66	struct device *dev = &pdev->dev;
 67	int irq;
 68
 69	irq = platform_get_irq(pdev, 0);
 70	if (irq < 0)
 71		return irq;
 72
 73	tsadc->domain = irq_domain_create_simple(dev_fwnode(dev), 2, 0, &mx25_tsadc_domain_ops,
 74						 tsadc);
 75	if (!tsadc->domain) {
 76		dev_err(dev, "Failed to add irq domain\n");
 77		return -ENOMEM;
 78	}
 79
 80	irq_set_chained_handler_and_data(irq, mx25_tsadc_irq_handler, tsadc);
 81
 82	return 0;
 83}
 84
 85static int mx25_tsadc_unset_irq(struct platform_device *pdev)
 86{
 87	struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
 88	int irq = platform_get_irq(pdev, 0);
 89
 90	if (irq >= 0) {
 91		irq_set_chained_handler_and_data(irq, NULL, NULL);
 92		irq_domain_remove(tsadc->domain);
 93	}
 94
 95	return 0;
 96}
 97
 98static void mx25_tsadc_setup_clk(struct platform_device *pdev,
 99				 struct mx25_tsadc *tsadc)
100{
101	unsigned clk_div;
102
103	/*
104	 * According to the datasheet the ADC clock should never
105	 * exceed 1,75 MHz. Base clock is the IPG and the ADC unit uses
106	 * a funny clock divider. To keep the ADC conversion time constant
107	 * adapt the ADC internal clock divider to the IPG clock rate.
108	 */
109
110	dev_dbg(&pdev->dev, "Found master clock at %lu Hz\n",
111		clk_get_rate(tsadc->clk));
112
113	clk_div = DIV_ROUND_UP(clk_get_rate(tsadc->clk), 1750000);
114	dev_dbg(&pdev->dev, "Setting up ADC clock divider to %u\n", clk_div);
115
116	/* adc clock = IPG clock / (2 * div + 2) */
117	clk_div -= 2;
118	clk_div /= 2;
119
120	/*
121	 * the ADC clock divider changes its behaviour when values below 4
122	 * are used: it is fixed to "/ 10" in this case
123	 */
124	clk_div = max_t(unsigned, 4, clk_div);
125
126	dev_dbg(&pdev->dev, "Resulting ADC conversion clock at %lu Hz\n",
127		clk_get_rate(tsadc->clk) / (2 * clk_div + 2));
128
129	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR,
130			   MX25_TGCR_ADCCLKCFG(0x1f),
131			   MX25_TGCR_ADCCLKCFG(clk_div));
132}
133
134static int mx25_tsadc_probe(struct platform_device *pdev)
135{
136	struct device *dev = &pdev->dev;
137	struct mx25_tsadc *tsadc;
138	int ret;
139	void __iomem *iomem;
140
141	tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
142	if (!tsadc)
143		return -ENOMEM;
144
145	iomem = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
146	if (IS_ERR(iomem))
147		return PTR_ERR(iomem);
148
149	tsadc->regs = devm_regmap_init_mmio(dev, iomem,
150					    &mx25_tsadc_regmap_config);
151	if (IS_ERR(tsadc->regs)) {
152		dev_err(dev, "Failed to initialize regmap\n");
153		return PTR_ERR(tsadc->regs);
154	}
155
156	tsadc->clk = devm_clk_get(dev, "ipg");
157	if (IS_ERR(tsadc->clk)) {
158		dev_err(dev, "Failed to get ipg clock\n");
159		return PTR_ERR(tsadc->clk);
160	}
161
162	/* setup clock according to the datasheet */
163	mx25_tsadc_setup_clk(pdev, tsadc);
164
165	/* Enable clock and reset the component */
166	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
167			   MX25_TGCR_CLK_EN);
168	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
169			   MX25_TGCR_TSC_RST);
170
171	/* Setup powersaving mode, but enable internal reference voltage */
172	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
173			   MX25_TGCR_POWERMODE_SAVE);
174	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
175			   MX25_TGCR_INTREFEN);
176
177	ret = mx25_tsadc_setup_irq(pdev, tsadc);
178	if (ret)
179		return ret;
180
181	platform_set_drvdata(pdev, tsadc);
182
183	ret = devm_of_platform_populate(dev);
184	if (ret)
185		goto err_irq;
186
187	return 0;
188
189err_irq:
190	mx25_tsadc_unset_irq(pdev);
191
192	return ret;
193}
194
195static void mx25_tsadc_remove(struct platform_device *pdev)
196{
197	mx25_tsadc_unset_irq(pdev);
198}
199
200static const struct of_device_id mx25_tsadc_ids[] = {
201	{ .compatible = "fsl,imx25-tsadc" },
202	{ /* Sentinel */ }
203};
204MODULE_DEVICE_TABLE(of, mx25_tsadc_ids);
205
206static struct platform_driver mx25_tsadc_driver = {
207	.driver = {
208		.name = "mx25-tsadc",
209		.of_match_table = mx25_tsadc_ids,
210	},
211	.probe = mx25_tsadc_probe,
212	.remove = mx25_tsadc_remove,
213};
214module_platform_driver(mx25_tsadc_driver);
215
216MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
217MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
218MODULE_LICENSE("GPL v2");
219MODULE_ALIAS("platform:mx25-tsadc");