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 struct regmap_config mx25_tsadc_regmap_config = {
20	.fast_io = true,
21	.max_register = 8,
22	.reg_bits = 32,
23	.val_bits = 32,
24	.reg_stride = 4,
25};
26
27static void mx25_tsadc_irq_handler(struct irq_desc *desc)
28{
29	struct mx25_tsadc *tsadc = irq_desc_get_handler_data(desc);
30	struct irq_chip *chip = irq_desc_get_chip(desc);
31	u32 status;
32
33	chained_irq_enter(chip, desc);
34
35	regmap_read(tsadc->regs, MX25_TSC_TGSR, &status);
36
37	if (status & MX25_TGSR_GCQ_INT)
38		generic_handle_irq(irq_find_mapping(tsadc->domain, 1));
39
40	if (status & MX25_TGSR_TCQ_INT)
41		generic_handle_irq(irq_find_mapping(tsadc->domain, 0));
42
43	chained_irq_exit(chip, desc);
44}
45
46static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq,
47				 irq_hw_number_t hwirq)
48{
49	struct mx25_tsadc *tsadc = d->host_data;
50
51	irq_set_chip_data(irq, tsadc);
52	irq_set_chip_and_handler(irq, &dummy_irq_chip,
53				 handle_level_irq);
54	irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);
55
56	return 0;
57}
58
59static const struct irq_domain_ops mx25_tsadc_domain_ops = {
60	.map = mx25_tsadc_domain_map,
61	.xlate = irq_domain_xlate_onecell,
62};
63
64static int mx25_tsadc_setup_irq(struct platform_device *pdev,
65				struct mx25_tsadc *tsadc)
66{
67	struct device *dev = &pdev->dev;
68	struct device_node *np = dev->of_node;
69	int irq;
70
71	irq = platform_get_irq(pdev, 0);
72	if (irq < 0)
73		return irq;
74
75	tsadc->domain = irq_domain_add_simple(np, 2, 0, &mx25_tsadc_domain_ops,
76					      tsadc);
77	if (!tsadc->domain) {
78		dev_err(dev, "Failed to add irq domain\n");
79		return -ENOMEM;
80	}
81
82	irq_set_chained_handler_and_data(irq, mx25_tsadc_irq_handler, tsadc);
83
84	return 0;
85}
86
87static int mx25_tsadc_unset_irq(struct platform_device *pdev)
88{
89	struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
90	int irq = platform_get_irq(pdev, 0);
91
92	if (irq >= 0) {
93		irq_set_chained_handler_and_data(irq, NULL, NULL);
94		irq_domain_remove(tsadc->domain);
95	}
96
97	return 0;
98}
99
100static void mx25_tsadc_setup_clk(struct platform_device *pdev,
101				 struct mx25_tsadc *tsadc)
102{
103	unsigned clk_div;
104
105	/*
106	 * According to the datasheet the ADC clock should never
107	 * exceed 1,75 MHz. Base clock is the IPG and the ADC unit uses
108	 * a funny clock divider. To keep the ADC conversion time constant
109	 * adapt the ADC internal clock divider to the IPG clock rate.
110	 */
111
112	dev_dbg(&pdev->dev, "Found master clock at %lu Hz\n",
113		clk_get_rate(tsadc->clk));
114
115	clk_div = DIV_ROUND_UP(clk_get_rate(tsadc->clk), 1750000);
116	dev_dbg(&pdev->dev, "Setting up ADC clock divider to %u\n", clk_div);
117
118	/* adc clock = IPG clock / (2 * div + 2) */
119	clk_div -= 2;
120	clk_div /= 2;
121
122	/*
123	 * the ADC clock divider changes its behaviour when values below 4
124	 * are used: it is fixed to "/ 10" in this case
125	 */
126	clk_div = max_t(unsigned, 4, clk_div);
127
128	dev_dbg(&pdev->dev, "Resulting ADC conversion clock at %lu Hz\n",
129		clk_get_rate(tsadc->clk) / (2 * clk_div + 2));
130
131	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR,
132			   MX25_TGCR_ADCCLKCFG(0x1f),
133			   MX25_TGCR_ADCCLKCFG(clk_div));
134}
135
136static int mx25_tsadc_probe(struct platform_device *pdev)
137{
138	struct device *dev = &pdev->dev;
139	struct mx25_tsadc *tsadc;
140	struct resource *res;
141	int ret;
142	void __iomem *iomem;
143
144	tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
145	if (!tsadc)
146		return -ENOMEM;
147
148	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149	iomem = devm_ioremap_resource(dev, res);
150	if (IS_ERR(iomem))
151		return PTR_ERR(iomem);
152
153	tsadc->regs = devm_regmap_init_mmio(dev, iomem,
154					    &mx25_tsadc_regmap_config);
155	if (IS_ERR(tsadc->regs)) {
156		dev_err(dev, "Failed to initialize regmap\n");
157		return PTR_ERR(tsadc->regs);
158	}
159
160	tsadc->clk = devm_clk_get(dev, "ipg");
161	if (IS_ERR(tsadc->clk)) {
162		dev_err(dev, "Failed to get ipg clock\n");
163		return PTR_ERR(tsadc->clk);
164	}
165
166	/* setup clock according to the datasheet */
167	mx25_tsadc_setup_clk(pdev, tsadc);
168
169	/* Enable clock and reset the component */
170	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
171			   MX25_TGCR_CLK_EN);
172	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
173			   MX25_TGCR_TSC_RST);
174
175	/* Setup powersaving mode, but enable internal reference voltage */
176	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
177			   MX25_TGCR_POWERMODE_SAVE);
178	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
179			   MX25_TGCR_INTREFEN);
180
181	ret = mx25_tsadc_setup_irq(pdev, tsadc);
182	if (ret)
183		return ret;
184
185	platform_set_drvdata(pdev, tsadc);
186
187	ret = devm_of_platform_populate(dev);
188	if (ret)
189		goto err_irq;
190
191	return 0;
192
193err_irq:
194	mx25_tsadc_unset_irq(pdev);
195
196	return ret;
197}
198
199static int mx25_tsadc_remove(struct platform_device *pdev)
200{
201	mx25_tsadc_unset_irq(pdev);
202
203	return 0;
204}
205
206static const struct of_device_id mx25_tsadc_ids[] = {
207	{ .compatible = "fsl,imx25-tsadc" },
208	{ /* Sentinel */ }
209};
210MODULE_DEVICE_TABLE(of, mx25_tsadc_ids);
211
212static struct platform_driver mx25_tsadc_driver = {
213	.driver = {
214		.name = "mx25-tsadc",
215		.of_match_table = of_match_ptr(mx25_tsadc_ids),
216	},
217	.probe = mx25_tsadc_probe,
218	.remove = mx25_tsadc_remove,
219};
220module_platform_driver(mx25_tsadc_driver);
221
222MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
223MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
224MODULE_LICENSE("GPL v2");
225MODULE_ALIAS("platform:mx25-tsadc");
226