1 // SPDX-License-Identifier: GPL-2.0-only
3 * TI/National Semiconductor LP3943 PWM driver
5 * Copyright 2013 Texas Instruments
7 * Author: Milo Kim <milo.kim@ti.com>
10 #include <linux/err.h>
11 #include <linux/mfd/lp3943.h>
12 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/pwm.h>
16 #include <linux/slab.h>
18 #define LP3943_MAX_DUTY 255
19 #define LP3943_MIN_PERIOD 6250
20 #define LP3943_MAX_PERIOD 1600000
23 struct lp3943
*lp3943
;
24 struct lp3943_platform_data
*pdata
;
25 struct lp3943_pwm_map pwm_map
[LP3943_NUM_PWMS
];
28 static inline struct lp3943_pwm
*to_lp3943_pwm(struct pwm_chip
*chip
)
30 return pwmchip_get_drvdata(chip
);
33 static struct lp3943_pwm_map
*
34 lp3943_pwm_request_map(struct lp3943_pwm
*lp3943_pwm
, int hwpwm
)
36 struct lp3943_platform_data
*pdata
= lp3943_pwm
->pdata
;
37 struct lp3943
*lp3943
= lp3943_pwm
->lp3943
;
38 struct lp3943_pwm_map
*pwm_map
= &lp3943_pwm
->pwm_map
[hwpwm
];
41 pwm_map
->output
= pdata
->pwms
[hwpwm
]->output
;
42 pwm_map
->num_outputs
= pdata
->pwms
[hwpwm
]->num_outputs
;
44 for (i
= 0; i
< pwm_map
->num_outputs
; i
++) {
45 offset
= pwm_map
->output
[i
];
47 /* Return an error if the pin is already assigned */
48 if (test_and_set_bit(offset
, &lp3943
->pin_used
))
49 return ERR_PTR(-EBUSY
);
55 static int lp3943_pwm_request(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
57 struct lp3943_pwm
*lp3943_pwm
= to_lp3943_pwm(chip
);
58 struct lp3943_pwm_map
*pwm_map
;
60 pwm_map
= lp3943_pwm_request_map(lp3943_pwm
, pwm
->hwpwm
);
62 return PTR_ERR(pwm_map
);
67 static void lp3943_pwm_free_map(struct lp3943_pwm
*lp3943_pwm
,
68 struct lp3943_pwm_map
*pwm_map
)
70 struct lp3943
*lp3943
= lp3943_pwm
->lp3943
;
73 for (i
= 0; i
< pwm_map
->num_outputs
; i
++) {
74 offset
= pwm_map
->output
[i
];
75 clear_bit(offset
, &lp3943
->pin_used
);
79 static void lp3943_pwm_free(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
81 struct lp3943_pwm
*lp3943_pwm
= to_lp3943_pwm(chip
);
82 struct lp3943_pwm_map
*pwm_map
= &lp3943_pwm
->pwm_map
[pwm
->hwpwm
];
84 lp3943_pwm_free_map(lp3943_pwm
, pwm_map
);
87 static int lp3943_pwm_config(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
88 u64 duty_ns
, u64 period_ns
)
90 struct lp3943_pwm
*lp3943_pwm
= to_lp3943_pwm(chip
);
91 struct lp3943
*lp3943
= lp3943_pwm
->lp3943
;
92 u8 val
, reg_duty
, reg_prescale
;
96 * How to configure the LP3943 PWMs
98 * 1) Period = 6250 ~ 1600000
99 * 2) Prescale = period / 6250 -1
100 * 3) Duty = input duty
102 * Prescale and duty are register values
105 if (pwm
->hwpwm
== 0) {
106 reg_prescale
= LP3943_REG_PRESCALE0
;
107 reg_duty
= LP3943_REG_PWM0
;
109 reg_prescale
= LP3943_REG_PRESCALE1
;
110 reg_duty
= LP3943_REG_PWM1
;
114 * Note that after this clamping, period_ns fits into an int. This is
115 * helpful because we can resort to integer division below instead of
116 * the (more expensive) 64 bit division.
118 period_ns
= clamp(period_ns
, (u64
)LP3943_MIN_PERIOD
, (u64
)LP3943_MAX_PERIOD
);
119 val
= (u8
)((int)period_ns
/ LP3943_MIN_PERIOD
- 1);
121 err
= lp3943_write_byte(lp3943
, reg_prescale
, val
);
125 duty_ns
= min(duty_ns
, period_ns
);
126 val
= (u8
)((int)duty_ns
* LP3943_MAX_DUTY
/ (int)period_ns
);
128 return lp3943_write_byte(lp3943
, reg_duty
, val
);
131 static int lp3943_pwm_set_mode(struct lp3943_pwm
*lp3943_pwm
,
132 struct lp3943_pwm_map
*pwm_map
,
135 struct lp3943
*lp3943
= lp3943_pwm
->lp3943
;
136 const struct lp3943_reg_cfg
*mux
= lp3943
->mux_cfg
;
139 for (i
= 0; i
< pwm_map
->num_outputs
; i
++) {
140 index
= pwm_map
->output
[i
];
141 err
= lp3943_update_bits(lp3943
, mux
[index
].reg
,
143 val
<< mux
[index
].shift
);
151 static int lp3943_pwm_enable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
153 struct lp3943_pwm
*lp3943_pwm
= to_lp3943_pwm(chip
);
154 struct lp3943_pwm_map
*pwm_map
= &lp3943_pwm
->pwm_map
[pwm
->hwpwm
];
158 val
= LP3943_DIM_PWM0
;
160 val
= LP3943_DIM_PWM1
;
163 * Each PWM generator is set to control any of outputs of LP3943.
164 * To enable/disable the PWM, these output pins should be configured.
167 return lp3943_pwm_set_mode(lp3943_pwm
, pwm_map
, val
);
170 static void lp3943_pwm_disable(struct pwm_chip
*chip
, struct pwm_device
*pwm
)
172 struct lp3943_pwm
*lp3943_pwm
= to_lp3943_pwm(chip
);
173 struct lp3943_pwm_map
*pwm_map
= &lp3943_pwm
->pwm_map
[pwm
->hwpwm
];
176 * LP3943 outputs are open-drain, so the pin should be configured
177 * when the PWM is disabled.
180 lp3943_pwm_set_mode(lp3943_pwm
, pwm_map
, LP3943_GPIO_OUT_HIGH
);
183 static int lp3943_pwm_apply(struct pwm_chip
*chip
, struct pwm_device
*pwm
,
184 const struct pwm_state
*state
)
188 if (state
->polarity
!= PWM_POLARITY_NORMAL
)
191 if (!state
->enabled
) {
192 if (pwm
->state
.enabled
)
193 lp3943_pwm_disable(chip
, pwm
);
197 err
= lp3943_pwm_config(chip
, pwm
, state
->duty_cycle
, state
->period
);
201 if (!pwm
->state
.enabled
)
202 err
= lp3943_pwm_enable(chip
, pwm
);
207 static const struct pwm_ops lp3943_pwm_ops
= {
208 .request
= lp3943_pwm_request
,
209 .free
= lp3943_pwm_free
,
210 .apply
= lp3943_pwm_apply
,
213 static int lp3943_pwm_parse_dt(struct device
*dev
,
214 struct lp3943_pwm
*lp3943_pwm
)
216 static const char * const name
[] = { "ti,pwm0", "ti,pwm1", };
217 struct device_node
*node
= dev
->of_node
;
218 struct lp3943_platform_data
*pdata
;
219 struct lp3943_pwm_map
*pwm_map
;
220 enum lp3943_pwm_output
*output
;
221 int i
, err
, proplen
, count
= 0;
227 pdata
= devm_kzalloc(dev
, sizeof(*pdata
), GFP_KERNEL
);
232 * Read the output map configuration from the device tree.
233 * Each of the two PWM generators can drive zero or more outputs.
236 for (i
= 0; i
< LP3943_NUM_PWMS
; i
++) {
237 if (!of_get_property(node
, name
[i
], &proplen
))
240 num_outputs
= proplen
/ sizeof(u32
);
241 if (num_outputs
== 0)
244 output
= devm_kcalloc(dev
, num_outputs
, sizeof(*output
),
249 err
= of_property_read_u32_array(node
, name
[i
], output
,
254 pwm_map
= devm_kzalloc(dev
, sizeof(*pwm_map
), GFP_KERNEL
);
258 pwm_map
->output
= output
;
259 pwm_map
->num_outputs
= num_outputs
;
260 pdata
->pwms
[i
] = pwm_map
;
268 lp3943_pwm
->pdata
= pdata
;
272 static int lp3943_pwm_probe(struct platform_device
*pdev
)
274 struct lp3943
*lp3943
= dev_get_drvdata(pdev
->dev
.parent
);
275 struct pwm_chip
*chip
;
276 struct lp3943_pwm
*lp3943_pwm
;
279 chip
= devm_pwmchip_alloc(&pdev
->dev
, LP3943_NUM_PWMS
, sizeof(*lp3943_pwm
));
281 return PTR_ERR(chip
);
282 lp3943_pwm
= to_lp3943_pwm(chip
);
284 lp3943_pwm
->pdata
= lp3943
->pdata
;
285 if (!lp3943_pwm
->pdata
) {
286 if (IS_ENABLED(CONFIG_OF
))
287 ret
= lp3943_pwm_parse_dt(&pdev
->dev
, lp3943_pwm
);
295 lp3943_pwm
->lp3943
= lp3943
;
296 chip
->ops
= &lp3943_pwm_ops
;
298 return devm_pwmchip_add(&pdev
->dev
, chip
);
302 static const struct of_device_id lp3943_pwm_of_match
[] = {
303 { .compatible
= "ti,lp3943-pwm", },
306 MODULE_DEVICE_TABLE(of
, lp3943_pwm_of_match
);
309 static struct platform_driver lp3943_pwm_driver
= {
310 .probe
= lp3943_pwm_probe
,
312 .name
= "lp3943-pwm",
313 .of_match_table
= of_match_ptr(lp3943_pwm_of_match
),
316 module_platform_driver(lp3943_pwm_driver
);
318 MODULE_DESCRIPTION("LP3943 PWM driver");
319 MODULE_ALIAS("platform:lp3943-pwm");
320 MODULE_AUTHOR("Milo Kim");
321 MODULE_LICENSE("GPL");