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
19 static 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
mx25_tsadc_irq_handler(struct irq_desc * desc)27 static 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_domain_irq(tsadc->domain, 1);
39
40 if (status & MX25_TGSR_TCQ_INT)
41 generic_handle_domain_irq(tsadc->domain, 0);
42
43 chained_irq_exit(chip, desc);
44 }
45
mx25_tsadc_domain_map(struct irq_domain * d,unsigned int irq,irq_hw_number_t hwirq)46 static 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
59 static const struct irq_domain_ops mx25_tsadc_domain_ops = {
60 .map = mx25_tsadc_domain_map,
61 .xlate = irq_domain_xlate_onecell,
62 };
63
mx25_tsadc_setup_irq(struct platform_device * pdev,struct mx25_tsadc * tsadc)64 static 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
mx25_tsadc_unset_irq(struct platform_device * pdev)87 static 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
mx25_tsadc_setup_clk(struct platform_device * pdev,struct mx25_tsadc * tsadc)100 static 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
mx25_tsadc_probe(struct platform_device * pdev)136 static int mx25_tsadc_probe(struct platform_device *pdev)
137 {
138 struct device *dev = &pdev->dev;
139 struct mx25_tsadc *tsadc;
140 int ret;
141 void __iomem *iomem;
142
143 tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
144 if (!tsadc)
145 return -ENOMEM;
146
147 iomem = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
148 if (IS_ERR(iomem))
149 return PTR_ERR(iomem);
150
151 tsadc->regs = devm_regmap_init_mmio(dev, iomem,
152 &mx25_tsadc_regmap_config);
153 if (IS_ERR(tsadc->regs)) {
154 dev_err(dev, "Failed to initialize regmap\n");
155 return PTR_ERR(tsadc->regs);
156 }
157
158 tsadc->clk = devm_clk_get(dev, "ipg");
159 if (IS_ERR(tsadc->clk)) {
160 dev_err(dev, "Failed to get ipg clock\n");
161 return PTR_ERR(tsadc->clk);
162 }
163
164 /* setup clock according to the datasheet */
165 mx25_tsadc_setup_clk(pdev, tsadc);
166
167 /* Enable clock and reset the component */
168 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
169 MX25_TGCR_CLK_EN);
170 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
171 MX25_TGCR_TSC_RST);
172
173 /* Setup powersaving mode, but enable internal reference voltage */
174 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
175 MX25_TGCR_POWERMODE_SAVE);
176 regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
177 MX25_TGCR_INTREFEN);
178
179 ret = mx25_tsadc_setup_irq(pdev, tsadc);
180 if (ret)
181 return ret;
182
183 platform_set_drvdata(pdev, tsadc);
184
185 ret = devm_of_platform_populate(dev);
186 if (ret)
187 goto err_irq;
188
189 return 0;
190
191 err_irq:
192 mx25_tsadc_unset_irq(pdev);
193
194 return ret;
195 }
196
mx25_tsadc_remove(struct platform_device * pdev)197 static int mx25_tsadc_remove(struct platform_device *pdev)
198 {
199 mx25_tsadc_unset_irq(pdev);
200
201 return 0;
202 }
203
204 static const struct of_device_id mx25_tsadc_ids[] = {
205 { .compatible = "fsl,imx25-tsadc" },
206 { /* Sentinel */ }
207 };
208 MODULE_DEVICE_TABLE(of, mx25_tsadc_ids);
209
210 static struct platform_driver mx25_tsadc_driver = {
211 .driver = {
212 .name = "mx25-tsadc",
213 .of_match_table = mx25_tsadc_ids,
214 },
215 .probe = mx25_tsadc_probe,
216 .remove = mx25_tsadc_remove,
217 };
218 module_platform_driver(mx25_tsadc_driver);
219
220 MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
221 MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
222 MODULE_LICENSE("GPL v2");
223 MODULE_ALIAS("platform:mx25-tsadc");
224