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1/*
2 * drivers/pwm/pwm-tegra.c
3 *
4 * Tegra pulse-width-modulation controller driver
5 *
6 * Copyright (c) 2010, NVIDIA Corporation.
7 * Based on arch/arm/plat-mxc/pwm.c by Sascha Hauer <s.hauer@pengutronix.de>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22 */
23
24#include <linux/clk.h>
25#include <linux/err.h>
26#include <linux/io.h>
27#include <linux/module.h>
28#include <linux/of.h>
29#include <linux/pwm.h>
30#include <linux/platform_device.h>
31#include <linux/slab.h>
32
33#define PWM_ENABLE (1 << 31)
34#define PWM_DUTY_WIDTH 8
35#define PWM_DUTY_SHIFT 16
36#define PWM_SCALE_WIDTH 13
37#define PWM_SCALE_SHIFT 0
38
39#define NUM_PWM 4
40
41struct tegra_pwm_chip {
42 struct pwm_chip chip;
43 struct device *dev;
44
45 struct clk *clk;
46
47 void __iomem *mmio_base;
48};
49
50static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
51{
52 return container_of(chip, struct tegra_pwm_chip, chip);
53}
54
55static inline u32 pwm_readl(struct tegra_pwm_chip *chip, unsigned int num)
56{
57 return readl(chip->mmio_base + (num << 4));
58}
59
60static inline void pwm_writel(struct tegra_pwm_chip *chip, unsigned int num,
61 unsigned long val)
62{
63 writel(val, chip->mmio_base + (num << 4));
64}
65
66static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
67 int duty_ns, int period_ns)
68{
69 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
70 unsigned long long c;
71 unsigned long rate, hz;
72 u32 val = 0;
73 int err;
74
75 /*
76 * Convert from duty_ns / period_ns to a fixed number of duty ticks
77 * per (1 << PWM_DUTY_WIDTH) cycles and make sure to round to the
78 * nearest integer during division.
79 */
80 c = duty_ns * ((1 << PWM_DUTY_WIDTH) - 1) + period_ns / 2;
81 do_div(c, period_ns);
82
83 val = (u32)c << PWM_DUTY_SHIFT;
84
85 /*
86 * Compute the prescaler value for which (1 << PWM_DUTY_WIDTH)
87 * cycles at the PWM clock rate will take period_ns nanoseconds.
88 */
89 rate = clk_get_rate(pc->clk) >> PWM_DUTY_WIDTH;
90 hz = NSEC_PER_SEC / period_ns;
91
92 rate = (rate + (hz / 2)) / hz;
93
94 /*
95 * Since the actual PWM divider is the register's frequency divider
96 * field minus 1, we need to decrement to get the correct value to
97 * write to the register.
98 */
99 if (rate > 0)
100 rate--;
101
102 /*
103 * Make sure that the rate will fit in the register's frequency
104 * divider field.
105 */
106 if (rate >> PWM_SCALE_WIDTH)
107 return -EINVAL;
108
109 val |= rate << PWM_SCALE_SHIFT;
110
111 /*
112 * If the PWM channel is disabled, make sure to turn on the clock
113 * before writing the register. Otherwise, keep it enabled.
114 */
115 if (!pwm_is_enabled(pwm)) {
116 err = clk_prepare_enable(pc->clk);
117 if (err < 0)
118 return err;
119 } else
120 val |= PWM_ENABLE;
121
122 pwm_writel(pc, pwm->hwpwm, val);
123
124 /*
125 * If the PWM is not enabled, turn the clock off again to save power.
126 */
127 if (!pwm_is_enabled(pwm))
128 clk_disable_unprepare(pc->clk);
129
130 return 0;
131}
132
133static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
134{
135 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
136 int rc = 0;
137 u32 val;
138
139 rc = clk_prepare_enable(pc->clk);
140 if (rc < 0)
141 return rc;
142
143 val = pwm_readl(pc, pwm->hwpwm);
144 val |= PWM_ENABLE;
145 pwm_writel(pc, pwm->hwpwm, val);
146
147 return 0;
148}
149
150static void tegra_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
151{
152 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
153 u32 val;
154
155 val = pwm_readl(pc, pwm->hwpwm);
156 val &= ~PWM_ENABLE;
157 pwm_writel(pc, pwm->hwpwm, val);
158
159 clk_disable_unprepare(pc->clk);
160}
161
162static const struct pwm_ops tegra_pwm_ops = {
163 .config = tegra_pwm_config,
164 .enable = tegra_pwm_enable,
165 .disable = tegra_pwm_disable,
166 .owner = THIS_MODULE,
167};
168
169static int tegra_pwm_probe(struct platform_device *pdev)
170{
171 struct tegra_pwm_chip *pwm;
172 struct resource *r;
173 int ret;
174
175 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
176 if (!pwm)
177 return -ENOMEM;
178
179 pwm->dev = &pdev->dev;
180
181 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
182 pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
183 if (IS_ERR(pwm->mmio_base))
184 return PTR_ERR(pwm->mmio_base);
185
186 platform_set_drvdata(pdev, pwm);
187
188 pwm->clk = devm_clk_get(&pdev->dev, NULL);
189 if (IS_ERR(pwm->clk))
190 return PTR_ERR(pwm->clk);
191
192 pwm->chip.dev = &pdev->dev;
193 pwm->chip.ops = &tegra_pwm_ops;
194 pwm->chip.base = -1;
195 pwm->chip.npwm = NUM_PWM;
196
197 ret = pwmchip_add(&pwm->chip);
198 if (ret < 0) {
199 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
200 return ret;
201 }
202
203 return 0;
204}
205
206static int tegra_pwm_remove(struct platform_device *pdev)
207{
208 struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
209 int i;
210
211 if (WARN_ON(!pc))
212 return -ENODEV;
213
214 for (i = 0; i < NUM_PWM; i++) {
215 struct pwm_device *pwm = &pc->chip.pwms[i];
216
217 if (!pwm_is_enabled(pwm))
218 if (clk_prepare_enable(pc->clk) < 0)
219 continue;
220
221 pwm_writel(pc, i, 0);
222
223 clk_disable_unprepare(pc->clk);
224 }
225
226 return pwmchip_remove(&pc->chip);
227}
228
229static const struct of_device_id tegra_pwm_of_match[] = {
230 { .compatible = "nvidia,tegra20-pwm" },
231 { .compatible = "nvidia,tegra30-pwm" },
232 { }
233};
234
235MODULE_DEVICE_TABLE(of, tegra_pwm_of_match);
236
237static struct platform_driver tegra_pwm_driver = {
238 .driver = {
239 .name = "tegra-pwm",
240 .of_match_table = tegra_pwm_of_match,
241 },
242 .probe = tegra_pwm_probe,
243 .remove = tegra_pwm_remove,
244};
245
246module_platform_driver(tegra_pwm_driver);
247
248MODULE_LICENSE("GPL");
249MODULE_AUTHOR("NVIDIA Corporation");
250MODULE_ALIAS("platform:tegra-pwm");
1/*
2 * drivers/pwm/pwm-tegra.c
3 *
4 * Tegra pulse-width-modulation controller driver
5 *
6 * Copyright (c) 2010, NVIDIA Corporation.
7 * Based on arch/arm/plat-mxc/pwm.c by Sascha Hauer <s.hauer@pengutronix.de>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
17 * more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22 */
23
24#include <linux/clk.h>
25#include <linux/err.h>
26#include <linux/io.h>
27#include <linux/module.h>
28#include <linux/of.h>
29#include <linux/of_device.h>
30#include <linux/pwm.h>
31#include <linux/platform_device.h>
32#include <linux/slab.h>
33#include <linux/reset.h>
34
35#define PWM_ENABLE (1 << 31)
36#define PWM_DUTY_WIDTH 8
37#define PWM_DUTY_SHIFT 16
38#define PWM_SCALE_WIDTH 13
39#define PWM_SCALE_SHIFT 0
40
41struct tegra_pwm_soc {
42 unsigned int num_channels;
43};
44
45struct tegra_pwm_chip {
46 struct pwm_chip chip;
47 struct device *dev;
48
49 struct clk *clk;
50 struct reset_control*rst;
51
52 void __iomem *regs;
53
54 const struct tegra_pwm_soc *soc;
55};
56
57static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
58{
59 return container_of(chip, struct tegra_pwm_chip, chip);
60}
61
62static inline u32 pwm_readl(struct tegra_pwm_chip *chip, unsigned int num)
63{
64 return readl(chip->regs + (num << 4));
65}
66
67static inline void pwm_writel(struct tegra_pwm_chip *chip, unsigned int num,
68 unsigned long val)
69{
70 writel(val, chip->regs + (num << 4));
71}
72
73static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
74 int duty_ns, int period_ns)
75{
76 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
77 unsigned long long c = duty_ns;
78 unsigned long rate, hz;
79 u32 val = 0;
80 int err;
81
82 /*
83 * Convert from duty_ns / period_ns to a fixed number of duty ticks
84 * per (1 << PWM_DUTY_WIDTH) cycles and make sure to round to the
85 * nearest integer during division.
86 */
87 c *= (1 << PWM_DUTY_WIDTH);
88 c += period_ns / 2;
89 do_div(c, period_ns);
90
91 val = (u32)c << PWM_DUTY_SHIFT;
92
93 /*
94 * Compute the prescaler value for which (1 << PWM_DUTY_WIDTH)
95 * cycles at the PWM clock rate will take period_ns nanoseconds.
96 */
97 rate = clk_get_rate(pc->clk) >> PWM_DUTY_WIDTH;
98 hz = NSEC_PER_SEC / period_ns;
99
100 rate = (rate + (hz / 2)) / hz;
101
102 /*
103 * Since the actual PWM divider is the register's frequency divider
104 * field minus 1, we need to decrement to get the correct value to
105 * write to the register.
106 */
107 if (rate > 0)
108 rate--;
109
110 /*
111 * Make sure that the rate will fit in the register's frequency
112 * divider field.
113 */
114 if (rate >> PWM_SCALE_WIDTH)
115 return -EINVAL;
116
117 val |= rate << PWM_SCALE_SHIFT;
118
119 /*
120 * If the PWM channel is disabled, make sure to turn on the clock
121 * before writing the register. Otherwise, keep it enabled.
122 */
123 if (!pwm_is_enabled(pwm)) {
124 err = clk_prepare_enable(pc->clk);
125 if (err < 0)
126 return err;
127 } else
128 val |= PWM_ENABLE;
129
130 pwm_writel(pc, pwm->hwpwm, val);
131
132 /*
133 * If the PWM is not enabled, turn the clock off again to save power.
134 */
135 if (!pwm_is_enabled(pwm))
136 clk_disable_unprepare(pc->clk);
137
138 return 0;
139}
140
141static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
142{
143 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
144 int rc = 0;
145 u32 val;
146
147 rc = clk_prepare_enable(pc->clk);
148 if (rc < 0)
149 return rc;
150
151 val = pwm_readl(pc, pwm->hwpwm);
152 val |= PWM_ENABLE;
153 pwm_writel(pc, pwm->hwpwm, val);
154
155 return 0;
156}
157
158static void tegra_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
159{
160 struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
161 u32 val;
162
163 val = pwm_readl(pc, pwm->hwpwm);
164 val &= ~PWM_ENABLE;
165 pwm_writel(pc, pwm->hwpwm, val);
166
167 clk_disable_unprepare(pc->clk);
168}
169
170static const struct pwm_ops tegra_pwm_ops = {
171 .config = tegra_pwm_config,
172 .enable = tegra_pwm_enable,
173 .disable = tegra_pwm_disable,
174 .owner = THIS_MODULE,
175};
176
177static int tegra_pwm_probe(struct platform_device *pdev)
178{
179 struct tegra_pwm_chip *pwm;
180 struct resource *r;
181 int ret;
182
183 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
184 if (!pwm)
185 return -ENOMEM;
186
187 pwm->soc = of_device_get_match_data(&pdev->dev);
188 pwm->dev = &pdev->dev;
189
190 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
191 pwm->regs = devm_ioremap_resource(&pdev->dev, r);
192 if (IS_ERR(pwm->regs))
193 return PTR_ERR(pwm->regs);
194
195 platform_set_drvdata(pdev, pwm);
196
197 pwm->clk = devm_clk_get(&pdev->dev, NULL);
198 if (IS_ERR(pwm->clk))
199 return PTR_ERR(pwm->clk);
200
201 pwm->rst = devm_reset_control_get(&pdev->dev, "pwm");
202 if (IS_ERR(pwm->rst)) {
203 ret = PTR_ERR(pwm->rst);
204 dev_err(&pdev->dev, "Reset control is not found: %d\n", ret);
205 return ret;
206 }
207
208 reset_control_deassert(pwm->rst);
209
210 pwm->chip.dev = &pdev->dev;
211 pwm->chip.ops = &tegra_pwm_ops;
212 pwm->chip.base = -1;
213 pwm->chip.npwm = pwm->soc->num_channels;
214
215 ret = pwmchip_add(&pwm->chip);
216 if (ret < 0) {
217 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
218 reset_control_assert(pwm->rst);
219 return ret;
220 }
221
222 return 0;
223}
224
225static int tegra_pwm_remove(struct platform_device *pdev)
226{
227 struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
228 unsigned int i;
229 int err;
230
231 if (WARN_ON(!pc))
232 return -ENODEV;
233
234 err = clk_prepare_enable(pc->clk);
235 if (err < 0)
236 return err;
237
238 for (i = 0; i < pc->chip.npwm; i++) {
239 struct pwm_device *pwm = &pc->chip.pwms[i];
240
241 if (!pwm_is_enabled(pwm))
242 if (clk_prepare_enable(pc->clk) < 0)
243 continue;
244
245 pwm_writel(pc, i, 0);
246
247 clk_disable_unprepare(pc->clk);
248 }
249
250 reset_control_assert(pc->rst);
251 clk_disable_unprepare(pc->clk);
252
253 return pwmchip_remove(&pc->chip);
254}
255
256static const struct tegra_pwm_soc tegra20_pwm_soc = {
257 .num_channels = 4,
258};
259
260static const struct tegra_pwm_soc tegra186_pwm_soc = {
261 .num_channels = 1,
262};
263
264static const struct of_device_id tegra_pwm_of_match[] = {
265 { .compatible = "nvidia,tegra20-pwm", .data = &tegra20_pwm_soc },
266 { .compatible = "nvidia,tegra186-pwm", .data = &tegra186_pwm_soc },
267 { }
268};
269
270MODULE_DEVICE_TABLE(of, tegra_pwm_of_match);
271
272static struct platform_driver tegra_pwm_driver = {
273 .driver = {
274 .name = "tegra-pwm",
275 .of_match_table = tegra_pwm_of_match,
276 },
277 .probe = tegra_pwm_probe,
278 .remove = tegra_pwm_remove,
279};
280
281module_platform_driver(tegra_pwm_driver);
282
283MODULE_LICENSE("GPL");
284MODULE_AUTHOR("NVIDIA Corporation");
285MODULE_ALIAS("platform:tegra-pwm");