Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 1 | /* |
| 2 | * simple driver for PWM (Pulse Width Modulator) controller |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * Derived from pxa PWM driver by eric miao <eric.miao@marvell.com> |
| 9 | */ |
| 10 | |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/platform_device.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/err.h> |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/io.h> |
| 18 | #include <linux/pwm.h> |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 19 | #include <linux/of_device.h> |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 20 | |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 21 | /* i.MX1 and i.MX21 share the same PWM function block: */ |
| 22 | |
| 23 | #define MX1_PWMC 0x00 /* PWM Control Register */ |
| 24 | #define MX1_PWMS 0x04 /* PWM Sample Register */ |
| 25 | #define MX1_PWMP 0x08 /* PWM Period Register */ |
| 26 | |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 27 | #define MX1_PWMC_EN (1 << 4) |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 28 | |
| 29 | /* i.MX27, i.MX31, i.MX35 share the same PWM function block: */ |
| 30 | |
| 31 | #define MX3_PWMCR 0x00 /* PWM Control Register */ |
| 32 | #define MX3_PWMSAR 0x0C /* PWM Sample Register */ |
| 33 | #define MX3_PWMPR 0x10 /* PWM Period Register */ |
| 34 | #define MX3_PWMCR_PRESCALER(x) (((x - 1) & 0xFFF) << 4) |
| 35 | #define MX3_PWMCR_DOZEEN (1 << 24) |
| 36 | #define MX3_PWMCR_WAITEN (1 << 23) |
| 37 | #define MX3_PWMCR_DBGEN (1 << 22) |
| 38 | #define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16) |
| 39 | #define MX3_PWMCR_CLKSRC_IPG (1 << 16) |
| 40 | #define MX3_PWMCR_EN (1 << 0) |
| 41 | |
| 42 | struct imx_chip { |
| 43 | struct clk *clk; |
| 44 | |
Sascha Hauer | 140827c | 2012-08-28 09:12:01 +0200 | [diff] [blame] | 45 | int enabled; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 46 | void __iomem *mmio_base; |
| 47 | |
| 48 | struct pwm_chip chip; |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 49 | |
| 50 | int (*config)(struct pwm_chip *chip, |
| 51 | struct pwm_device *pwm, int duty_ns, int period_ns); |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 52 | void (*set_enable)(struct pwm_chip *chip, bool enable); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 53 | }; |
| 54 | |
| 55 | #define to_imx_chip(chip) container_of(chip, struct imx_chip, chip) |
| 56 | |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 57 | static int imx_pwm_config_v1(struct pwm_chip *chip, |
| 58 | struct pwm_device *pwm, int duty_ns, int period_ns) |
| 59 | { |
| 60 | struct imx_chip *imx = to_imx_chip(chip); |
| 61 | |
| 62 | /* |
| 63 | * The PWM subsystem allows for exact frequencies. However, |
| 64 | * I cannot connect a scope on my device to the PWM line and |
| 65 | * thus cannot provide the program the PWM controller |
| 66 | * exactly. Instead, I'm relying on the fact that the |
| 67 | * Bootloader (u-boot or WinCE+haret) has programmed the PWM |
| 68 | * function group already. So I'll just modify the PWM sample |
| 69 | * register to follow the ratio of duty_ns vs. period_ns |
| 70 | * accordingly. |
| 71 | * |
| 72 | * This is good enough for programming the brightness of |
| 73 | * the LCD backlight. |
| 74 | * |
| 75 | * The real implementation would divide PERCLK[0] first by |
| 76 | * both the prescaler (/1 .. /128) and then by CLKSEL |
| 77 | * (/2 .. /16). |
| 78 | */ |
| 79 | u32 max = readl(imx->mmio_base + MX1_PWMP); |
| 80 | u32 p = max * duty_ns / period_ns; |
| 81 | writel(max - p, imx->mmio_base + MX1_PWMS); |
| 82 | |
| 83 | return 0; |
| 84 | } |
| 85 | |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 86 | static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable) |
| 87 | { |
| 88 | struct imx_chip *imx = to_imx_chip(chip); |
| 89 | u32 val; |
| 90 | |
| 91 | val = readl(imx->mmio_base + MX1_PWMC); |
| 92 | |
| 93 | if (enable) |
| 94 | val |= MX1_PWMC_EN; |
| 95 | else |
| 96 | val &= ~MX1_PWMC_EN; |
| 97 | |
| 98 | writel(val, imx->mmio_base + MX1_PWMC); |
| 99 | } |
| 100 | |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 101 | static int imx_pwm_config_v2(struct pwm_chip *chip, |
| 102 | struct pwm_device *pwm, int duty_ns, int period_ns) |
| 103 | { |
| 104 | struct imx_chip *imx = to_imx_chip(chip); |
| 105 | unsigned long long c; |
| 106 | unsigned long period_cycles, duty_cycles, prescale; |
| 107 | u32 cr; |
| 108 | |
| 109 | c = clk_get_rate(imx->clk); |
| 110 | c = c * period_ns; |
| 111 | do_div(c, 1000000000); |
| 112 | period_cycles = c; |
| 113 | |
| 114 | prescale = period_cycles / 0x10000 + 1; |
| 115 | |
| 116 | period_cycles /= prescale; |
| 117 | c = (unsigned long long)period_cycles * duty_ns; |
| 118 | do_div(c, period_ns); |
| 119 | duty_cycles = c; |
| 120 | |
| 121 | /* |
| 122 | * according to imx pwm RM, the real period value should be |
| 123 | * PERIOD value in PWMPR plus 2. |
| 124 | */ |
| 125 | if (period_cycles > 2) |
| 126 | period_cycles -= 2; |
| 127 | else |
| 128 | period_cycles = 0; |
| 129 | |
| 130 | writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); |
| 131 | writel(period_cycles, imx->mmio_base + MX3_PWMPR); |
| 132 | |
| 133 | cr = MX3_PWMCR_PRESCALER(prescale) | |
| 134 | MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | |
Sascha Hauer | 8d1c24b | 2012-08-28 12:03:29 +0200 | [diff] [blame^] | 135 | MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH; |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 136 | |
| 137 | if (imx->enabled) |
| 138 | cr |= MX3_PWMCR_EN; |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 139 | |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 140 | writel(cr, imx->mmio_base + MX3_PWMCR); |
| 141 | |
| 142 | return 0; |
| 143 | } |
| 144 | |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 145 | static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable) |
| 146 | { |
| 147 | struct imx_chip *imx = to_imx_chip(chip); |
| 148 | u32 val; |
| 149 | |
| 150 | val = readl(imx->mmio_base + MX3_PWMCR); |
| 151 | |
| 152 | if (enable) |
| 153 | val |= MX3_PWMCR_EN; |
| 154 | else |
| 155 | val &= ~MX3_PWMCR_EN; |
| 156 | |
| 157 | writel(val, imx->mmio_base + MX3_PWMCR); |
| 158 | } |
| 159 | |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 160 | static int imx_pwm_config(struct pwm_chip *chip, |
| 161 | struct pwm_device *pwm, int duty_ns, int period_ns) |
| 162 | { |
| 163 | struct imx_chip *imx = to_imx_chip(chip); |
| 164 | |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 165 | return imx->config(chip, pwm, duty_ns, period_ns); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 166 | } |
| 167 | |
| 168 | static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 169 | { |
| 170 | struct imx_chip *imx = to_imx_chip(chip); |
Sascha Hauer | 140827c | 2012-08-28 09:12:01 +0200 | [diff] [blame] | 171 | int ret; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 172 | |
Sascha Hauer | 140827c | 2012-08-28 09:12:01 +0200 | [diff] [blame] | 173 | ret = clk_prepare_enable(imx->clk); |
| 174 | if (ret) |
| 175 | return ret; |
| 176 | |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 177 | imx->set_enable(chip, true); |
| 178 | |
Sascha Hauer | 140827c | 2012-08-28 09:12:01 +0200 | [diff] [blame] | 179 | imx->enabled = 1; |
| 180 | |
| 181 | return 0; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 182 | } |
| 183 | |
| 184 | static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) |
| 185 | { |
| 186 | struct imx_chip *imx = to_imx_chip(chip); |
| 187 | |
Sascha Hauer | 66ad6a6 | 2012-08-28 11:39:25 +0200 | [diff] [blame] | 188 | imx->set_enable(chip, false); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 189 | |
Sascha Hauer | 140827c | 2012-08-28 09:12:01 +0200 | [diff] [blame] | 190 | clk_disable_unprepare(imx->clk); |
| 191 | imx->enabled = 0; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 192 | } |
| 193 | |
| 194 | static struct pwm_ops imx_pwm_ops = { |
| 195 | .enable = imx_pwm_enable, |
| 196 | .disable = imx_pwm_disable, |
| 197 | .config = imx_pwm_config, |
| 198 | .owner = THIS_MODULE, |
| 199 | }; |
| 200 | |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 201 | struct imx_pwm_data { |
| 202 | int (*config)(struct pwm_chip *chip, |
| 203 | struct pwm_device *pwm, int duty_ns, int period_ns); |
| 204 | void (*set_enable)(struct pwm_chip *chip, bool enable); |
| 205 | }; |
| 206 | |
| 207 | static struct imx_pwm_data imx_pwm_data_v1 = { |
| 208 | .config = imx_pwm_config_v1, |
| 209 | .set_enable = imx_pwm_set_enable_v1, |
| 210 | }; |
| 211 | |
| 212 | static struct imx_pwm_data imx_pwm_data_v2 = { |
| 213 | .config = imx_pwm_config_v2, |
| 214 | .set_enable = imx_pwm_set_enable_v2, |
| 215 | }; |
| 216 | |
| 217 | static const struct of_device_id imx_pwm_dt_ids[] = { |
| 218 | { .compatible = "fsl,imx1-pwm", .data = &imx_pwm_data_v1, }, |
| 219 | { .compatible = "fsl,imx27-pwm", .data = &imx_pwm_data_v2, }, |
| 220 | { /* sentinel */ } |
| 221 | }; |
| 222 | MODULE_DEVICE_TABLE(of, imx_pwm_dt_ids); |
| 223 | |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 224 | static int __devinit imx_pwm_probe(struct platform_device *pdev) |
| 225 | { |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 226 | const struct of_device_id *of_id = |
| 227 | of_match_device(imx_pwm_dt_ids, &pdev->dev); |
| 228 | struct imx_pwm_data *data; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 229 | struct imx_chip *imx; |
| 230 | struct resource *r; |
| 231 | int ret = 0; |
| 232 | |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 233 | if (!of_id) |
| 234 | return -ENODEV; |
| 235 | |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 236 | imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 237 | if (imx == NULL) { |
| 238 | dev_err(&pdev->dev, "failed to allocate memory\n"); |
| 239 | return -ENOMEM; |
| 240 | } |
| 241 | |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 242 | imx->clk = devm_clk_get(&pdev->dev, "pwm"); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 243 | |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 244 | if (IS_ERR(imx->clk)) |
| 245 | return PTR_ERR(imx->clk); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 246 | |
| 247 | imx->chip.ops = &imx_pwm_ops; |
| 248 | imx->chip.dev = &pdev->dev; |
| 249 | imx->chip.base = -1; |
| 250 | imx->chip.npwm = 1; |
| 251 | |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 252 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 253 | if (r == NULL) { |
| 254 | dev_err(&pdev->dev, "no memory resource defined\n"); |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 255 | return -ENODEV; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 256 | } |
| 257 | |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 258 | imx->mmio_base = devm_request_and_ioremap(&pdev->dev, r); |
| 259 | if (imx->mmio_base == NULL) |
| 260 | return -EADDRNOTAVAIL; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 261 | |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 262 | data = of_id->data; |
| 263 | imx->config = data->config; |
| 264 | imx->set_enable = data->set_enable; |
Sascha Hauer | 19e7333 | 2012-07-03 17:28:14 +0200 | [diff] [blame] | 265 | |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 266 | ret = pwmchip_add(&imx->chip); |
| 267 | if (ret < 0) |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 268 | return ret; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 269 | |
| 270 | platform_set_drvdata(pdev, imx); |
| 271 | return 0; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 272 | } |
| 273 | |
| 274 | static int __devexit imx_pwm_remove(struct platform_device *pdev) |
| 275 | { |
| 276 | struct imx_chip *imx; |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 277 | |
| 278 | imx = platform_get_drvdata(pdev); |
| 279 | if (imx == NULL) |
| 280 | return -ENODEV; |
| 281 | |
Axel Lin | a9970e3 | 2012-07-01 08:27:23 +0800 | [diff] [blame] | 282 | return pwmchip_remove(&imx->chip); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 283 | } |
| 284 | |
| 285 | static struct platform_driver imx_pwm_driver = { |
| 286 | .driver = { |
Philipp Zabel | 479e2e3 | 2012-06-25 16:16:25 +0200 | [diff] [blame] | 287 | .name = "imx-pwm", |
| 288 | .of_match_table = of_match_ptr(imx_pwm_dt_ids), |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 289 | }, |
| 290 | .probe = imx_pwm_probe, |
| 291 | .remove = __devexit_p(imx_pwm_remove), |
| 292 | }; |
| 293 | |
Sascha Hauer | 208d038 | 2012-08-28 08:27:40 +0200 | [diff] [blame] | 294 | module_platform_driver(imx_pwm_driver); |
Sascha Hauer | 2969324 | 2012-03-15 10:04:35 +0100 | [diff] [blame] | 295 | |
| 296 | MODULE_LICENSE("GPL v2"); |
| 297 | MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); |