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authorNaveen Krishna Ch <ch.naveen@samsung.com>2013-10-16 01:30:42 -0400
committerWolfram Sang <wsa@the-dreams.de>2013-11-01 09:10:01 -0400
commit8a73cd4cfa159918da405d9645deca842590e2fe (patch)
treeaa16ca938392e4247875b7080797930ec2f17659
parent043a3f113ce41e3e6fdbb49551df75e82e8c4ae7 (diff)
i2c: exynos5: add High Speed I2C controller driver
Adds support for High Speed I2C driver found in Exynos5 and later SoCs from Samsung. Driver only supports Device Tree method. Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com> Signed-off-by: Taekgyun Ko <taeggyun.ko@samsung.com> Reviewed-by: Simon Glass <sjg@google.com> Signed-off-by: Yuvaraj Kumar C D <yuvaraj.cd@samsung.com> Signed-off-by: Andrew Bresticker <abrestic@google.com> [wsa: rebased to v3.12-rc4 (no of_i2c.h anymore)] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c-exynos5.txt44
-rw-r--r--drivers/i2c/busses/Kconfig7
-rw-r--r--drivers/i2c/busses/Makefile1
-rw-r--r--drivers/i2c/busses/i2c-exynos5.c774
4 files changed, 826 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
new file mode 100644
index 000000000000..056732cfdcee
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-exynos5.txt
@@ -0,0 +1,44 @@
1* Samsung's High Speed I2C controller
2
3The Samsung's High Speed I2C controller is used to interface with I2C devices
4at various speeds ranging from 100khz to 3.4Mhz.
5
6Required properties:
7 - compatible: value should be.
8 -> "samsung,exynos5-hsi2c", for i2c compatible with exynos5 hsi2c.
9 - reg: physical base address of the controller and length of memory mapped
10 region.
11 - interrupts: interrupt number to the cpu.
12 - #address-cells: always 1 (for i2c addresses)
13 - #size-cells: always 0
14
15 - Pinctrl:
16 - pinctrl-0: Pin control group to be used for this controller.
17 - pinctrl-names: Should contain only one value - "default".
18
19Optional properties:
20 - clock-frequency: Desired operating frequency in Hz of the bus.
21 -> If not specified, the bus operates in fast-speed mode at
22 at 100khz.
23 -> If specified, the bus operates in high-speed mode only if the
24 clock-frequency is >= 1Mhz.
25
26Example:
27
28hsi2c@12ca0000 {
29 compatible = "samsung,exynos5-hsi2c";
30 reg = <0x12ca0000 0x100>;
31 interrupts = <56>;
32 clock-frequency = <100000>;
33
34 pinctrl-0 = <&i2c4_bus>;
35 pinctrl-names = "default";
36
37 #address-cells = <1>;
38 #size-cells = <0>;
39
40 s2mps11_pmic@66 {
41 compatible = "samsung,s2mps11-pmic";
42 reg = <0x66>;
43 };
44};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 7c4bb071c123..80e55305656f 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -436,6 +436,13 @@ config I2C_EG20T
436 ML7213/ML7223/ML7831 is companion chip for Intel Atom E6xx series. 436 ML7213/ML7223/ML7831 is companion chip for Intel Atom E6xx series.
437 ML7213/ML7223/ML7831 is completely compatible for Intel EG20T PCH. 437 ML7213/ML7223/ML7831 is completely compatible for Intel EG20T PCH.
438 438
439config I2C_EXYNOS5
440 tristate "Exynos5 high-speed I2C driver"
441 depends on ARCH_EXYNOS5 && OF
442 help
443 Say Y here to include support for high-speed I2C controller in the
444 Exynos5 based Samsung SoCs.
445
439config I2C_GPIO 446config I2C_GPIO
440 tristate "GPIO-based bitbanging I2C" 447 tristate "GPIO-based bitbanging I2C"
441 depends on GPIOLIB 448 depends on GPIOLIB
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index d00997f3eb3b..d1ad3712d905 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -42,6 +42,7 @@ i2c-designware-platform-objs := i2c-designware-platdrv.o
42obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o 42obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o
43i2c-designware-pci-objs := i2c-designware-pcidrv.o 43i2c-designware-pci-objs := i2c-designware-pcidrv.o
44obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o 44obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o
45obj-$(CONFIG_I2C_EXYNOS5) += i2c-exynos5.o
45obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o 46obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
46obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o 47obj-$(CONFIG_I2C_HIGHLANDER) += i2c-highlander.o
47obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o 48obj-$(CONFIG_I2C_IBM_IIC) += i2c-ibm_iic.o
diff --git a/drivers/i2c/busses/i2c-exynos5.c b/drivers/i2c/busses/i2c-exynos5.c
new file mode 100644
index 000000000000..aca3991b7636
--- /dev/null
+++ b/drivers/i2c/busses/i2c-exynos5.c
@@ -0,0 +1,774 @@
1/**
2 * i2c-exynos5.c - Samsung Exynos5 I2C Controller Driver
3 *
4 * Copyright (C) 2013 Samsung Electronics Co., Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9*/
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13
14#include <linux/i2c.h>
15#include <linux/init.h>
16#include <linux/time.h>
17#include <linux/interrupt.h>
18#include <linux/delay.h>
19#include <linux/errno.h>
20#include <linux/err.h>
21#include <linux/platform_device.h>
22#include <linux/clk.h>
23#include <linux/slab.h>
24#include <linux/io.h>
25#include <linux/of_address.h>
26#include <linux/of_irq.h>
27#include <linux/spinlock.h>
28
29/*
30 * HSI2C controller from Samsung supports 2 modes of operation
31 * 1. Auto mode: Where in master automatically controls the whole transaction
32 * 2. Manual mode: Software controls the transaction by issuing commands
33 * START, READ, WRITE, STOP, RESTART in I2C_MANUAL_CMD register.
34 *
35 * Operation mode can be selected by setting AUTO_MODE bit in I2C_CONF register
36 *
37 * Special bits are available for both modes of operation to set commands
38 * and for checking transfer status
39 */
40
41/* Register Map */
42#define HSI2C_CTL 0x00
43#define HSI2C_FIFO_CTL 0x04
44#define HSI2C_TRAILIG_CTL 0x08
45#define HSI2C_CLK_CTL 0x0C
46#define HSI2C_CLK_SLOT 0x10
47#define HSI2C_INT_ENABLE 0x20
48#define HSI2C_INT_STATUS 0x24
49#define HSI2C_ERR_STATUS 0x2C
50#define HSI2C_FIFO_STATUS 0x30
51#define HSI2C_TX_DATA 0x34
52#define HSI2C_RX_DATA 0x38
53#define HSI2C_CONF 0x40
54#define HSI2C_AUTO_CONF 0x44
55#define HSI2C_TIMEOUT 0x48
56#define HSI2C_MANUAL_CMD 0x4C
57#define HSI2C_TRANS_STATUS 0x50
58#define HSI2C_TIMING_HS1 0x54
59#define HSI2C_TIMING_HS2 0x58
60#define HSI2C_TIMING_HS3 0x5C
61#define HSI2C_TIMING_FS1 0x60
62#define HSI2C_TIMING_FS2 0x64
63#define HSI2C_TIMING_FS3 0x68
64#define HSI2C_TIMING_SLA 0x6C
65#define HSI2C_ADDR 0x70
66
67/* I2C_CTL Register bits */
68#define HSI2C_FUNC_MODE_I2C (1u << 0)
69#define HSI2C_MASTER (1u << 3)
70#define HSI2C_RXCHON (1u << 6)
71#define HSI2C_TXCHON (1u << 7)
72#define HSI2C_SW_RST (1u << 31)
73
74/* I2C_FIFO_CTL Register bits */
75#define HSI2C_RXFIFO_EN (1u << 0)
76#define HSI2C_TXFIFO_EN (1u << 1)
77#define HSI2C_RXFIFO_TRIGGER_LEVEL(x) ((x) << 4)
78#define HSI2C_TXFIFO_TRIGGER_LEVEL(x) ((x) << 16)
79
80/* As per user manual FIFO max depth is 64bytes */
81#define HSI2C_FIFO_MAX 0x40
82/* default trigger levels for Tx and Rx FIFOs */
83#define HSI2C_DEF_TXFIFO_LVL (HSI2C_FIFO_MAX - 0x30)
84#define HSI2C_DEF_RXFIFO_LVL (HSI2C_FIFO_MAX - 0x10)
85
86/* I2C_TRAILING_CTL Register bits */
87#define HSI2C_TRAILING_COUNT (0xf)
88
89/* I2C_INT_EN Register bits */
90#define HSI2C_INT_TX_ALMOSTEMPTY_EN (1u << 0)
91#define HSI2C_INT_RX_ALMOSTFULL_EN (1u << 1)
92#define HSI2C_INT_TRAILING_EN (1u << 6)
93#define HSI2C_INT_I2C_EN (1u << 9)
94
95/* I2C_INT_STAT Register bits */
96#define HSI2C_INT_TX_ALMOSTEMPTY (1u << 0)
97#define HSI2C_INT_RX_ALMOSTFULL (1u << 1)
98#define HSI2C_INT_TX_UNDERRUN (1u << 2)
99#define HSI2C_INT_TX_OVERRUN (1u << 3)
100#define HSI2C_INT_RX_UNDERRUN (1u << 4)
101#define HSI2C_INT_RX_OVERRUN (1u << 5)
102#define HSI2C_INT_TRAILING (1u << 6)
103#define HSI2C_INT_I2C (1u << 9)
104
105/* I2C_FIFO_STAT Register bits */
106#define HSI2C_RX_FIFO_EMPTY (1u << 24)
107#define HSI2C_RX_FIFO_FULL (1u << 23)
108#define HSI2C_RX_FIFO_LVL(x) ((x >> 16) & 0x7f)
109#define HSI2C_TX_FIFO_EMPTY (1u << 8)
110#define HSI2C_TX_FIFO_FULL (1u << 7)
111#define HSI2C_TX_FIFO_LVL(x) ((x >> 0) & 0x7f)
112
113/* I2C_CONF Register bits */
114#define HSI2C_AUTO_MODE (1u << 31)
115#define HSI2C_10BIT_ADDR_MODE (1u << 30)
116#define HSI2C_HS_MODE (1u << 29)
117
118/* I2C_AUTO_CONF Register bits */
119#define HSI2C_READ_WRITE (1u << 16)
120#define HSI2C_STOP_AFTER_TRANS (1u << 17)
121#define HSI2C_MASTER_RUN (1u << 31)
122
123/* I2C_TIMEOUT Register bits */
124#define HSI2C_TIMEOUT_EN (1u << 31)
125#define HSI2C_TIMEOUT_MASK 0xff
126
127/* I2C_TRANS_STATUS register bits */
128#define HSI2C_MASTER_BUSY (1u << 17)
129#define HSI2C_SLAVE_BUSY (1u << 16)
130#define HSI2C_TIMEOUT_AUTO (1u << 4)
131#define HSI2C_NO_DEV (1u << 3)
132#define HSI2C_NO_DEV_ACK (1u << 2)
133#define HSI2C_TRANS_ABORT (1u << 1)
134#define HSI2C_TRANS_DONE (1u << 0)
135
136/* I2C_ADDR register bits */
137#define HSI2C_SLV_ADDR_SLV(x) ((x & 0x3ff) << 0)
138#define HSI2C_SLV_ADDR_MAS(x) ((x & 0x3ff) << 10)
139#define HSI2C_MASTER_ID(x) ((x & 0xff) << 24)
140#define MASTER_ID(x) ((x & 0x7) + 0x08)
141
142/*
143 * Controller operating frequency, timing values for operation
144 * are calculated against this frequency
145 */
146#define HSI2C_HS_TX_CLOCK 1000000
147#define HSI2C_FS_TX_CLOCK 100000
148#define HSI2C_HIGH_SPD 1
149#define HSI2C_FAST_SPD 0
150
151#define EXYNOS5_I2C_TIMEOUT (msecs_to_jiffies(1000))
152
153struct exynos5_i2c {
154 struct i2c_adapter adap;
155 unsigned int suspended:1;
156
157 struct i2c_msg *msg;
158 struct completion msg_complete;
159 unsigned int msg_ptr;
160
161 unsigned int irq;
162
163 void __iomem *regs;
164 struct clk *clk;
165 struct device *dev;
166 int state;
167
168 spinlock_t lock; /* IRQ synchronization */
169
170 /*
171 * Since the TRANS_DONE bit is cleared on read, and we may read it
172 * either during an IRQ or after a transaction, keep track of its
173 * state here.
174 */
175 int trans_done;
176
177 /* Controller operating frequency */
178 unsigned int fs_clock;
179 unsigned int hs_clock;
180
181 /*
182 * HSI2C Controller can operate in
183 * 1. High speed upto 3.4Mbps
184 * 2. Fast speed upto 1Mbps
185 */
186 int speed_mode;
187};
188
189static const struct of_device_id exynos5_i2c_match[] = {
190 { .compatible = "samsung,exynos5-hsi2c" },
191 {},
192};
193MODULE_DEVICE_TABLE(of, exynos5_i2c_match);
194
195static void exynos5_i2c_clr_pend_irq(struct exynos5_i2c *i2c)
196{
197 writel(readl(i2c->regs + HSI2C_INT_STATUS),
198 i2c->regs + HSI2C_INT_STATUS);
199}
200
201/*
202 * exynos5_i2c_set_timing: updates the registers with appropriate
203 * timing values calculated
204 *
205 * Returns 0 on success, -EINVAL if the cycle length cannot
206 * be calculated.
207 */
208static int exynos5_i2c_set_timing(struct exynos5_i2c *i2c, int mode)
209{
210 u32 i2c_timing_s1;
211 u32 i2c_timing_s2;
212 u32 i2c_timing_s3;
213 u32 i2c_timing_sla;
214 unsigned int t_start_su, t_start_hd;
215 unsigned int t_stop_su;
216 unsigned int t_data_su, t_data_hd;
217 unsigned int t_scl_l, t_scl_h;
218 unsigned int t_sr_release;
219 unsigned int t_ftl_cycle;
220 unsigned int clkin = clk_get_rate(i2c->clk);
221 unsigned int div, utemp0 = 0, utemp1 = 0, clk_cycle;
222 unsigned int op_clk = (mode == HSI2C_HIGH_SPD) ?
223 i2c->hs_clock : i2c->fs_clock;
224
225 /*
226 * FPCLK / FI2C =
227 * (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2) + 8 + 2 * FLT_CYCLE
228 * utemp0 = (CLK_DIV + 1) * (TSCLK_L + TSCLK_H + 2)
229 * utemp1 = (TSCLK_L + TSCLK_H + 2)
230 */
231 t_ftl_cycle = (readl(i2c->regs + HSI2C_CONF) >> 16) & 0x7;
232 utemp0 = (clkin / op_clk) - 8 - 2 * t_ftl_cycle;
233
234 /* CLK_DIV max is 256 */
235 for (div = 0; div < 256; div++) {
236 utemp1 = utemp0 / (div + 1);
237
238 /*
239 * SCL_L and SCL_H each has max value of 255
240 * Hence, For the clk_cycle to the have right value
241 * utemp1 has to be less then 512 and more than 4.
242 */
243 if ((utemp1 < 512) && (utemp1 > 4)) {
244 clk_cycle = utemp1 - 2;
245 break;
246 } else if (div == 255) {
247 dev_warn(i2c->dev, "Failed to calculate divisor");
248 return -EINVAL;
249 }
250 }
251
252 t_scl_l = clk_cycle / 2;
253 t_scl_h = clk_cycle / 2;
254 t_start_su = t_scl_l;
255 t_start_hd = t_scl_l;
256 t_stop_su = t_scl_l;
257 t_data_su = t_scl_l / 2;
258 t_data_hd = t_scl_l / 2;
259 t_sr_release = clk_cycle;
260
261 i2c_timing_s1 = t_start_su << 24 | t_start_hd << 16 | t_stop_su << 8;
262 i2c_timing_s2 = t_data_su << 24 | t_scl_l << 8 | t_scl_h << 0;
263 i2c_timing_s3 = div << 16 | t_sr_release << 0;
264 i2c_timing_sla = t_data_hd << 0;
265
266 dev_dbg(i2c->dev, "tSTART_SU: %X, tSTART_HD: %X, tSTOP_SU: %X\n",
267 t_start_su, t_start_hd, t_stop_su);
268 dev_dbg(i2c->dev, "tDATA_SU: %X, tSCL_L: %X, tSCL_H: %X\n",
269 t_data_su, t_scl_l, t_scl_h);
270 dev_dbg(i2c->dev, "nClkDiv: %X, tSR_RELEASE: %X\n",
271 div, t_sr_release);
272 dev_dbg(i2c->dev, "tDATA_HD: %X\n", t_data_hd);
273
274 if (mode == HSI2C_HIGH_SPD) {
275 writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_HS1);
276 writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_HS2);
277 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_HS3);
278 } else {
279 writel(i2c_timing_s1, i2c->regs + HSI2C_TIMING_FS1);
280 writel(i2c_timing_s2, i2c->regs + HSI2C_TIMING_FS2);
281 writel(i2c_timing_s3, i2c->regs + HSI2C_TIMING_FS3);
282 }
283 writel(i2c_timing_sla, i2c->regs + HSI2C_TIMING_SLA);
284
285 return 0;
286}
287
288static int exynos5_hsi2c_clock_setup(struct exynos5_i2c *i2c)
289{
290 /*
291 * Configure the Fast speed timing values
292 * Even the High Speed mode initially starts with Fast mode
293 */
294 if (exynos5_i2c_set_timing(i2c, HSI2C_FAST_SPD)) {
295 dev_err(i2c->dev, "HSI2C FS Clock set up failed\n");
296 return -EINVAL;
297 }
298
299 /* configure the High speed timing values */
300 if (i2c->speed_mode == HSI2C_HIGH_SPD) {
301 if (exynos5_i2c_set_timing(i2c, HSI2C_HIGH_SPD)) {
302 dev_err(i2c->dev, "HSI2C HS Clock set up failed\n");
303 return -EINVAL;
304 }
305 }
306
307 return 0;
308}
309
310/*
311 * exynos5_i2c_init: configures the controller for I2C functionality
312 * Programs I2C controller for Master mode operation
313 */
314static void exynos5_i2c_init(struct exynos5_i2c *i2c)
315{
316 u32 i2c_conf = readl(i2c->regs + HSI2C_CONF);
317 u32 i2c_timeout = readl(i2c->regs + HSI2C_TIMEOUT);
318
319 /* Clear to disable Timeout */
320 i2c_timeout &= ~HSI2C_TIMEOUT_EN;
321 writel(i2c_timeout, i2c->regs + HSI2C_TIMEOUT);
322
323 writel((HSI2C_FUNC_MODE_I2C | HSI2C_MASTER),
324 i2c->regs + HSI2C_CTL);
325 writel(HSI2C_TRAILING_COUNT, i2c->regs + HSI2C_TRAILIG_CTL);
326
327 if (i2c->speed_mode == HSI2C_HIGH_SPD) {
328 writel(HSI2C_MASTER_ID(MASTER_ID(i2c->adap.nr)),
329 i2c->regs + HSI2C_ADDR);
330 i2c_conf |= HSI2C_HS_MODE;
331 }
332
333 writel(i2c_conf | HSI2C_AUTO_MODE, i2c->regs + HSI2C_CONF);
334}
335
336static void exynos5_i2c_reset(struct exynos5_i2c *i2c)
337{
338 u32 i2c_ctl;
339
340 /* Set and clear the bit for reset */
341 i2c_ctl = readl(i2c->regs + HSI2C_CTL);
342 i2c_ctl |= HSI2C_SW_RST;
343 writel(i2c_ctl, i2c->regs + HSI2C_CTL);
344
345 i2c_ctl = readl(i2c->regs + HSI2C_CTL);
346 i2c_ctl &= ~HSI2C_SW_RST;
347 writel(i2c_ctl, i2c->regs + HSI2C_CTL);
348
349 /* We don't expect calculations to fail during the run */
350 exynos5_hsi2c_clock_setup(i2c);
351 /* Initialize the configure registers */
352 exynos5_i2c_init(i2c);
353}
354
355/*
356 * exynos5_i2c_irq: top level IRQ servicing routine
357 *
358 * INT_STATUS registers gives the interrupt details. Further,
359 * FIFO_STATUS or TRANS_STATUS registers are to be check for detailed
360 * state of the bus.
361 */
362static irqreturn_t exynos5_i2c_irq(int irqno, void *dev_id)
363{
364 struct exynos5_i2c *i2c = dev_id;
365 u32 fifo_level, int_status, fifo_status, trans_status;
366 unsigned char byte;
367 int len = 0;
368
369 i2c->state = -EINVAL;
370
371 spin_lock(&i2c->lock);
372
373 int_status = readl(i2c->regs + HSI2C_INT_STATUS);
374 writel(int_status, i2c->regs + HSI2C_INT_STATUS);
375 fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
376
377 /* handle interrupt related to the transfer status */
378 if (int_status & HSI2C_INT_I2C) {
379 trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
380 if (trans_status & HSI2C_NO_DEV_ACK) {
381 dev_dbg(i2c->dev, "No ACK from device\n");
382 i2c->state = -ENXIO;
383 goto stop;
384 } else if (trans_status & HSI2C_NO_DEV) {
385 dev_dbg(i2c->dev, "No device\n");
386 i2c->state = -ENXIO;
387 goto stop;
388 } else if (trans_status & HSI2C_TRANS_ABORT) {
389 dev_dbg(i2c->dev, "Deal with arbitration lose\n");
390 i2c->state = -EAGAIN;
391 goto stop;
392 } else if (trans_status & HSI2C_TIMEOUT_AUTO) {
393 dev_dbg(i2c->dev, "Accessing device timed out\n");
394 i2c->state = -EAGAIN;
395 goto stop;
396 } else if (trans_status & HSI2C_TRANS_DONE) {
397 i2c->trans_done = 1;
398 i2c->state = 0;
399 }
400 }
401
402 if ((i2c->msg->flags & I2C_M_RD) && (int_status &
403 (HSI2C_INT_TRAILING | HSI2C_INT_RX_ALMOSTFULL))) {
404 fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
405 fifo_level = HSI2C_RX_FIFO_LVL(fifo_status);
406 len = min(fifo_level, i2c->msg->len - i2c->msg_ptr);
407
408 while (len > 0) {
409 byte = (unsigned char)
410 readl(i2c->regs + HSI2C_RX_DATA);
411 i2c->msg->buf[i2c->msg_ptr++] = byte;
412 len--;
413 }
414 i2c->state = 0;
415 } else if (int_status & HSI2C_INT_TX_ALMOSTEMPTY) {
416 fifo_status = readl(i2c->regs + HSI2C_FIFO_STATUS);
417 fifo_level = HSI2C_TX_FIFO_LVL(fifo_status);
418
419 len = HSI2C_FIFO_MAX - fifo_level;
420 if (len > (i2c->msg->len - i2c->msg_ptr))
421 len = i2c->msg->len - i2c->msg_ptr;
422
423 while (len > 0) {
424 byte = i2c->msg->buf[i2c->msg_ptr++];
425 writel(byte, i2c->regs + HSI2C_TX_DATA);
426 len--;
427 }
428 i2c->state = 0;
429 }
430
431 stop:
432 if ((i2c->trans_done && (i2c->msg->len == i2c->msg_ptr)) ||
433 (i2c->state < 0)) {
434 writel(0, i2c->regs + HSI2C_INT_ENABLE);
435 exynos5_i2c_clr_pend_irq(i2c);
436 complete(&i2c->msg_complete);
437 }
438
439 spin_unlock(&i2c->lock);
440
441 return IRQ_HANDLED;
442}
443
444/*
445 * exynos5_i2c_wait_bus_idle
446 *
447 * Wait for the bus to go idle, indicated by the MASTER_BUSY bit being
448 * cleared.
449 *
450 * Returns -EBUSY if the bus cannot be bought to idle
451 */
452static int exynos5_i2c_wait_bus_idle(struct exynos5_i2c *i2c)
453{
454 unsigned long stop_time;
455 u32 trans_status;
456
457 /* wait for 100 milli seconds for the bus to be idle */
458 stop_time = jiffies + msecs_to_jiffies(100) + 1;
459 do {
460 trans_status = readl(i2c->regs + HSI2C_TRANS_STATUS);
461 if (!(trans_status & HSI2C_MASTER_BUSY))
462 return 0;
463
464 usleep_range(50, 200);
465 } while (time_before(jiffies, stop_time));
466
467 return -EBUSY;
468}
469
470/*
471 * exynos5_i2c_message_start: Configures the bus and starts the xfer
472 * i2c: struct exynos5_i2c pointer for the current bus
473 * stop: Enables stop after transfer if set. Set for last transfer of
474 * in the list of messages.
475 *
476 * Configures the bus for read/write function
477 * Sets chip address to talk to, message length to be sent.
478 * Enables appropriate interrupts and sends start xfer command.
479 */
480static void exynos5_i2c_message_start(struct exynos5_i2c *i2c, int stop)
481{
482 u32 i2c_ctl;
483 u32 int_en = HSI2C_INT_I2C_EN;
484 u32 i2c_auto_conf = 0;
485 u32 fifo_ctl;
486 unsigned long flags;
487
488 i2c_ctl = readl(i2c->regs + HSI2C_CTL);
489 i2c_ctl &= ~(HSI2C_TXCHON | HSI2C_RXCHON);
490 fifo_ctl = HSI2C_RXFIFO_EN | HSI2C_TXFIFO_EN;
491
492 if (i2c->msg->flags & I2C_M_RD) {
493 i2c_ctl |= HSI2C_RXCHON;
494
495 i2c_auto_conf = HSI2C_READ_WRITE;
496
497 fifo_ctl |= HSI2C_RXFIFO_TRIGGER_LEVEL(HSI2C_DEF_TXFIFO_LVL);
498 int_en |= (HSI2C_INT_RX_ALMOSTFULL_EN |
499 HSI2C_INT_TRAILING_EN);
500 } else {
501 i2c_ctl |= HSI2C_TXCHON;
502
503 fifo_ctl |= HSI2C_TXFIFO_TRIGGER_LEVEL(HSI2C_DEF_RXFIFO_LVL);
504 int_en |= HSI2C_INT_TX_ALMOSTEMPTY_EN;
505 }
506
507 writel(HSI2C_SLV_ADDR_MAS(i2c->msg->addr), i2c->regs + HSI2C_ADDR);
508
509 writel(fifo_ctl, i2c->regs + HSI2C_FIFO_CTL);
510 writel(i2c_ctl, i2c->regs + HSI2C_CTL);
511
512
513 /*
514 * Enable interrupts before starting the transfer so that we don't
515 * miss any INT_I2C interrupts.
516 */
517 spin_lock_irqsave(&i2c->lock, flags);
518 writel(int_en, i2c->regs + HSI2C_INT_ENABLE);
519
520 if (stop == 1)
521 i2c_auto_conf |= HSI2C_STOP_AFTER_TRANS;
522 i2c_auto_conf |= i2c->msg->len;
523 i2c_auto_conf |= HSI2C_MASTER_RUN;
524 writel(i2c_auto_conf, i2c->regs + HSI2C_AUTO_CONF);
525 spin_unlock_irqrestore(&i2c->lock, flags);
526}
527
528static int exynos5_i2c_xfer_msg(struct exynos5_i2c *i2c,
529 struct i2c_msg *msgs, int stop)
530{
531 unsigned long timeout;
532 int ret;
533
534 i2c->msg = msgs;
535 i2c->msg_ptr = 0;
536 i2c->trans_done = 0;
537
538 INIT_COMPLETION(i2c->msg_complete);
539
540 exynos5_i2c_message_start(i2c, stop);
541
542 timeout = wait_for_completion_timeout(&i2c->msg_complete,
543 EXYNOS5_I2C_TIMEOUT);
544 if (timeout == 0)
545 ret = -ETIMEDOUT;
546 else
547 ret = i2c->state;
548
549 /*
550 * If this is the last message to be transfered (stop == 1)
551 * Then check if the bus can be brought back to idle.
552 */
553 if (ret == 0 && stop)
554 ret = exynos5_i2c_wait_bus_idle(i2c);
555
556 if (ret < 0) {
557 exynos5_i2c_reset(i2c);
558 if (ret == -ETIMEDOUT)
559 dev_warn(i2c->dev, "%s timeout\n",
560 (msgs->flags & I2C_M_RD) ? "rx" : "tx");
561 }
562
563 /* Return the state as in interrupt routine */
564 return ret;
565}
566
567static int exynos5_i2c_xfer(struct i2c_adapter *adap,
568 struct i2c_msg *msgs, int num)
569{
570 struct exynos5_i2c *i2c = (struct exynos5_i2c *)adap->algo_data;
571 int i = 0, ret = 0, stop = 0;
572
573 if (i2c->suspended) {
574 dev_err(i2c->dev, "HS-I2C is not initialzed.\n");
575 return -EIO;
576 }
577
578 clk_prepare_enable(i2c->clk);
579
580 for (i = 0; i < num; i++, msgs++) {
581 stop = (i == num - 1);
582
583 ret = exynos5_i2c_xfer_msg(i2c, msgs, stop);
584
585 if (ret < 0)
586 goto out;
587 }
588
589 if (i == num) {
590 ret = num;
591 } else {
592 /* Only one message, cannot access the device */
593 if (i == 1)
594 ret = -EREMOTEIO;
595 else
596 ret = i;
597
598 dev_warn(i2c->dev, "xfer message failed\n");
599 }
600
601 out:
602 clk_disable_unprepare(i2c->clk);
603 return ret;
604}
605
606static u32 exynos5_i2c_func(struct i2c_adapter *adap)
607{
608 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
609}
610
611static const struct i2c_algorithm exynos5_i2c_algorithm = {
612 .master_xfer = exynos5_i2c_xfer,
613 .functionality = exynos5_i2c_func,
614};
615
616static int exynos5_i2c_probe(struct platform_device *pdev)
617{
618 struct device_node *np = pdev->dev.of_node;
619 struct exynos5_i2c *i2c;
620 struct resource *mem;
621 unsigned int op_clock;
622 int ret;
623
624 i2c = devm_kzalloc(&pdev->dev, sizeof(struct exynos5_i2c), GFP_KERNEL);
625 if (!i2c) {
626 dev_err(&pdev->dev, "no memory for state\n");
627 return -ENOMEM;
628 }
629
630 if (of_property_read_u32(np, "clock-frequency", &op_clock)) {
631 i2c->speed_mode = HSI2C_FAST_SPD;
632 i2c->fs_clock = HSI2C_FS_TX_CLOCK;
633 } else {
634 if (op_clock >= HSI2C_HS_TX_CLOCK) {
635 i2c->speed_mode = HSI2C_HIGH_SPD;
636 i2c->fs_clock = HSI2C_FS_TX_CLOCK;
637 i2c->hs_clock = op_clock;
638 } else {
639 i2c->speed_mode = HSI2C_FAST_SPD;
640 i2c->fs_clock = op_clock;
641 }
642 }
643
644 strlcpy(i2c->adap.name, "exynos5-i2c", sizeof(i2c->adap.name));
645 i2c->adap.owner = THIS_MODULE;
646 i2c->adap.algo = &exynos5_i2c_algorithm;
647 i2c->adap.retries = 3;
648
649 i2c->dev = &pdev->dev;
650 i2c->clk = devm_clk_get(&pdev->dev, "hsi2c");
651 if (IS_ERR(i2c->clk)) {
652 dev_err(&pdev->dev, "cannot get clock\n");
653 return -ENOENT;
654 }
655
656 clk_prepare_enable(i2c->clk);
657
658 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
659 i2c->regs = devm_ioremap_resource(&pdev->dev, mem);
660 if (IS_ERR(i2c->regs)) {
661 ret = PTR_ERR(i2c->regs);
662 goto err_clk;
663 }
664
665 i2c->adap.dev.of_node = np;
666 i2c->adap.algo_data = i2c;
667 i2c->adap.dev.parent = &pdev->dev;
668
669 /* Clear pending interrupts from u-boot or misc causes */
670 exynos5_i2c_clr_pend_irq(i2c);
671
672 spin_lock_init(&i2c->lock);
673 init_completion(&i2c->msg_complete);
674
675 i2c->irq = ret = platform_get_irq(pdev, 0);
676 if (ret <= 0) {
677 dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
678 ret = -EINVAL;
679 goto err_clk;
680 }
681
682 ret = devm_request_irq(&pdev->dev, i2c->irq, exynos5_i2c_irq,
683 IRQF_NO_SUSPEND | IRQF_ONESHOT,
684 dev_name(&pdev->dev), i2c);
685
686 if (ret != 0) {
687 dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", i2c->irq);
688 goto err_clk;
689 }
690
691 ret = exynos5_hsi2c_clock_setup(i2c);
692 if (ret)
693 goto err_clk;
694
695 exynos5_i2c_init(i2c);
696
697 ret = i2c_add_adapter(&i2c->adap);
698 if (ret < 0) {
699 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
700 goto err_clk;
701 }
702
703 platform_set_drvdata(pdev, i2c);
704
705 clk_disable_unprepare(i2c->clk);
706
707 return 0;
708
709 err_clk:
710 clk_disable_unprepare(i2c->clk);
711 return ret;
712}
713
714static int exynos5_i2c_remove(struct platform_device *pdev)
715{
716 struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
717
718 i2c_del_adapter(&i2c->adap);
719 clk_disable_unprepare(i2c->clk);
720
721 return 0;
722}
723
724static int exynos5_i2c_suspend_noirq(struct device *dev)
725{
726 struct platform_device *pdev = to_platform_device(dev);
727 struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
728
729 i2c->suspended = 1;
730
731 return 0;
732}
733
734static int exynos5_i2c_resume_noirq(struct device *dev)
735{
736 struct platform_device *pdev = to_platform_device(dev);
737 struct exynos5_i2c *i2c = platform_get_drvdata(pdev);
738 int ret = 0;
739
740 clk_prepare_enable(i2c->clk);
741
742 ret = exynos5_hsi2c_clock_setup(i2c);
743 if (ret) {
744 clk_disable_unprepare(i2c->clk);
745 return ret;
746 }
747
748 exynos5_i2c_init(i2c);
749 clk_disable_unprepare(i2c->clk);
750 i2c->suspended = 0;
751
752 return 0;
753}
754
755static SIMPLE_DEV_PM_OPS(exynos5_i2c_dev_pm_ops, exynos5_i2c_suspend_noirq,
756 exynos5_i2c_resume_noirq);
757
758static struct platform_driver exynos5_i2c_driver = {
759 .probe = exynos5_i2c_probe,
760 .remove = exynos5_i2c_remove,
761 .driver = {
762 .owner = THIS_MODULE,
763 .name = "exynos5-hsi2c",
764 .pm = &exynos5_i2c_dev_pm_ops,
765 .of_match_table = exynos5_i2c_match,
766 },
767};
768
769module_platform_driver(exynos5_i2c_driver);
770
771MODULE_DESCRIPTION("Exynos5 HS-I2C Bus driver");
772MODULE_AUTHOR("Naveen Krishna Chatradhi, <ch.naveen@samsung.com>");
773MODULE_AUTHOR("Taekgyun Ko, <taeggyun.ko@samsung.com>");
774MODULE_LICENSE("GPL v2");
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-05 12:23:18 -0500