summaryrefslogtreecommitdiffstats
path: root/drivers/mfd/fsl-imx25-tsadc.c
blob: b3767c3141e58a0fd9af028ced1ad13f67726c77 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdesc.h>
#include <linux/irqdomain.h>
#include <linux/irq.h>
#include <linux/mfd/imx25-tsadc.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

static struct regmap_config mx25_tsadc_regmap_config = {
	.fast_io = true,
	.max_register = 8,
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
};

static void mx25_tsadc_irq_handler(struct irq_desc *desc)
{
	struct mx25_tsadc *tsadc = irq_desc_get_handler_data(desc);
	struct irq_chip *chip = irq_desc_get_chip(desc);
	u32 status;

	chained_irq_enter(chip, desc);

	regmap_read(tsadc->regs, MX25_TSC_TGSR, &status);

	if (status & MX25_TGSR_GCQ_INT)
		generic_handle_irq(irq_find_mapping(tsadc->domain, 1));

	if (status & MX25_TGSR_TCQ_INT)
		generic_handle_irq(irq_find_mapping(tsadc->domain, 0));

	chained_irq_exit(chip, desc);
}

static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq,
				 irq_hw_number_t hwirq)
{
	struct mx25_tsadc *tsadc = d->host_data;

	irq_set_chip_data(irq, tsadc);
	irq_set_chip_and_handler(irq, &dummy_irq_chip,
				 handle_level_irq);
	irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);

	return 0;
}

static const struct irq_domain_ops mx25_tsadc_domain_ops = {
	.map = mx25_tsadc_domain_map,
	.xlate = irq_domain_xlate_onecell,
};

static int mx25_tsadc_setup_irq(struct platform_device *pdev,
				struct mx25_tsadc *tsadc)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	int irq;

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
		dev_err(dev, "Failed to get irq\n");
		return irq;
	}

	tsadc->domain = irq_domain_add_simple(np, 2, 0, &mx25_tsadc_domain_ops,
					      tsadc);
	if (!tsadc->domain) {
		dev_err(dev, "Failed to add irq domain\n");
		return -ENOMEM;
	}

	irq_set_chained_handler(irq, mx25_tsadc_irq_handler);
	irq_set_handler_data(irq, tsadc);

	return 0;
}

static void mx25_tsadc_setup_clk(struct platform_device *pdev,
				 struct mx25_tsadc *tsadc)
{
	unsigned clk_div;

	/*
	 * According to the datasheet the ADC clock should never
	 * exceed 1,75 MHz. Base clock is the IPG and the ADC unit uses
	 * a funny clock divider. To keep the ADC conversion time constant
	 * adapt the ADC internal clock divider to the IPG clock rate.
	 */

	dev_dbg(&pdev->dev, "Found master clock at %lu Hz\n",
		clk_get_rate(tsadc->clk));

	clk_div = DIV_ROUND_UP(clk_get_rate(tsadc->clk), 1750000);
	dev_dbg(&pdev->dev, "Setting up ADC clock divider to %u\n", clk_div);

	/* adc clock = IPG clock / (2 * div + 2) */
	clk_div -= 2;
	clk_div /= 2;

	/*
	 * the ADC clock divider changes its behaviour when values below 4
	 * are used: it is fixed to "/ 10" in this case
	 */
	clk_div = max_t(unsigned, 4, clk_div);

	dev_dbg(&pdev->dev, "Resulting ADC conversion clock at %lu Hz\n",
		clk_get_rate(tsadc->clk) / (2 * clk_div + 2));

	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR,
			   MX25_TGCR_ADCCLKCFG(0x1f),
			   MX25_TGCR_ADCCLKCFG(clk_div));
}

static int mx25_tsadc_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct mx25_tsadc *tsadc;
	struct resource *res;
	int ret;
	void __iomem *iomem;

	tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
	if (!tsadc)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	iomem = devm_ioremap_resource(dev, res);
	if (IS_ERR(iomem))
		return PTR_ERR(iomem);

	tsadc->regs = devm_regmap_init_mmio(dev, iomem,
					    &mx25_tsadc_regmap_config);
	if (IS_ERR(tsadc->regs)) {
		dev_err(dev, "Failed to initialize regmap\n");
		return PTR_ERR(tsadc->regs);
	}

	tsadc->clk = devm_clk_get(dev, "ipg");
	if (IS_ERR(tsadc->clk)) {
		dev_err(dev, "Failed to get ipg clock\n");
		return PTR_ERR(tsadc->clk);
	}

	/* setup clock according to the datasheet */
	mx25_tsadc_setup_clk(pdev, tsadc);

	/* Enable clock and reset the component */
	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
			   MX25_TGCR_CLK_EN);
	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
			   MX25_TGCR_TSC_RST);

	/* Setup powersaving mode, but enable internal reference voltage */
	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
			   MX25_TGCR_POWERMODE_SAVE);
	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
			   MX25_TGCR_INTREFEN);

	ret = mx25_tsadc_setup_irq(pdev, tsadc);
	if (ret)
		return ret;

	platform_set_drvdata(pdev, tsadc);

	return devm_of_platform_populate(dev);
}

static const struct of_device_id mx25_tsadc_ids[] = {
	{ .compatible = "fsl,imx25-tsadc" },
	{ /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, mx25_tsadc_ids);

static struct platform_driver mx25_tsadc_driver = {
	.driver = {
		.name = "mx25-tsadc",
		.of_match_table = of_match_ptr(mx25_tsadc_ids),
	},
	.probe = mx25_tsadc_probe,
};
module_platform_driver(mx25_tsadc_driver);

MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:mx25-tsadc");