1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
4*4882a593Smuzhiyun */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include <linux/clk.h>
7*4882a593Smuzhiyun #include <linux/i2c.h>
8*4882a593Smuzhiyun #include <linux/iopoll.h>
9*4882a593Smuzhiyun #include <linux/interrupt.h>
10*4882a593Smuzhiyun #include <linux/io.h>
11*4882a593Smuzhiyun #include <linux/module.h>
12*4882a593Smuzhiyun #include <linux/platform_device.h>
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun #define UNIPHIER_FI2C_CR 0x00 /* control register */
15*4882a593Smuzhiyun #define UNIPHIER_FI2C_CR_MST BIT(3) /* master mode */
16*4882a593Smuzhiyun #define UNIPHIER_FI2C_CR_STA BIT(2) /* start condition */
17*4882a593Smuzhiyun #define UNIPHIER_FI2C_CR_STO BIT(1) /* stop condition */
18*4882a593Smuzhiyun #define UNIPHIER_FI2C_CR_NACK BIT(0) /* do not return ACK */
19*4882a593Smuzhiyun #define UNIPHIER_FI2C_DTTX 0x04 /* TX FIFO */
20*4882a593Smuzhiyun #define UNIPHIER_FI2C_DTTX_CMD BIT(8) /* send command (slave addr) */
21*4882a593Smuzhiyun #define UNIPHIER_FI2C_DTTX_RD BIT(0) /* read transaction */
22*4882a593Smuzhiyun #define UNIPHIER_FI2C_DTRX 0x04 /* RX FIFO */
23*4882a593Smuzhiyun #define UNIPHIER_FI2C_SLAD 0x0c /* slave address */
24*4882a593Smuzhiyun #define UNIPHIER_FI2C_CYC 0x10 /* clock cycle control */
25*4882a593Smuzhiyun #define UNIPHIER_FI2C_LCTL 0x14 /* clock low period control */
26*4882a593Smuzhiyun #define UNIPHIER_FI2C_SSUT 0x18 /* restart/stop setup time control */
27*4882a593Smuzhiyun #define UNIPHIER_FI2C_DSUT 0x1c /* data setup time control */
28*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT 0x20 /* interrupt status */
29*4882a593Smuzhiyun #define UNIPHIER_FI2C_IE 0x24 /* interrupt enable */
30*4882a593Smuzhiyun #define UNIPHIER_FI2C_IC 0x28 /* interrupt clear */
31*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_TE BIT(9) /* TX FIFO empty */
32*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_RF BIT(8) /* RX FIFO full */
33*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_TC BIT(7) /* send complete (STOP) */
34*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_RC BIT(6) /* receive complete (STOP) */
35*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_TB BIT(5) /* sent specified bytes */
36*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_RB BIT(4) /* received specified bytes */
37*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_NA BIT(2) /* no ACK */
38*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_AL BIT(1) /* arbitration lost */
39*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR 0x2c /* status register */
40*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_DB BIT(12) /* device busy */
41*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_STS BIT(11) /* stop condition detected */
42*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_BB BIT(8) /* bus busy */
43*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_RFF BIT(3) /* RX FIFO full */
44*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_RNE BIT(2) /* RX FIFO not empty */
45*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_TNF BIT(1) /* TX FIFO not full */
46*4882a593Smuzhiyun #define UNIPHIER_FI2C_SR_TFE BIT(0) /* TX FIFO empty */
47*4882a593Smuzhiyun #define UNIPHIER_FI2C_RST 0x34 /* reset control */
48*4882a593Smuzhiyun #define UNIPHIER_FI2C_RST_TBRST BIT(2) /* clear TX FIFO */
49*4882a593Smuzhiyun #define UNIPHIER_FI2C_RST_RBRST BIT(1) /* clear RX FIFO */
50*4882a593Smuzhiyun #define UNIPHIER_FI2C_RST_RST BIT(0) /* forcible bus reset */
51*4882a593Smuzhiyun #define UNIPHIER_FI2C_BM 0x38 /* bus monitor */
52*4882a593Smuzhiyun #define UNIPHIER_FI2C_BM_SDAO BIT(3) /* output for SDA line */
53*4882a593Smuzhiyun #define UNIPHIER_FI2C_BM_SDAS BIT(2) /* readback of SDA line */
54*4882a593Smuzhiyun #define UNIPHIER_FI2C_BM_SCLO BIT(1) /* output for SCL line */
55*4882a593Smuzhiyun #define UNIPHIER_FI2C_BM_SCLS BIT(0) /* readback of SCL line */
56*4882a593Smuzhiyun #define UNIPHIER_FI2C_NOISE 0x3c /* noise filter control */
57*4882a593Smuzhiyun #define UNIPHIER_FI2C_TBC 0x40 /* TX byte count setting */
58*4882a593Smuzhiyun #define UNIPHIER_FI2C_RBC 0x44 /* RX byte count setting */
59*4882a593Smuzhiyun #define UNIPHIER_FI2C_TBCM 0x48 /* TX byte count monitor */
60*4882a593Smuzhiyun #define UNIPHIER_FI2C_RBCM 0x4c /* RX byte count monitor */
61*4882a593Smuzhiyun #define UNIPHIER_FI2C_BRST 0x50 /* bus reset */
62*4882a593Smuzhiyun #define UNIPHIER_FI2C_BRST_FOEN BIT(1) /* normal operation */
63*4882a593Smuzhiyun #define UNIPHIER_FI2C_BRST_RSCL BIT(0) /* release SCL */
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_FAULTS \
66*4882a593Smuzhiyun (UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
67*4882a593Smuzhiyun #define UNIPHIER_FI2C_INT_STOP \
68*4882a593Smuzhiyun (UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun #define UNIPHIER_FI2C_RD BIT(0)
71*4882a593Smuzhiyun #define UNIPHIER_FI2C_STOP BIT(1)
72*4882a593Smuzhiyun #define UNIPHIER_FI2C_MANUAL_NACK BIT(2)
73*4882a593Smuzhiyun #define UNIPHIER_FI2C_BYTE_WISE BIT(3)
74*4882a593Smuzhiyun #define UNIPHIER_FI2C_DEFER_STOP_COMP BIT(4)
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun #define UNIPHIER_FI2C_FIFO_SIZE 8
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun struct uniphier_fi2c_priv {
79*4882a593Smuzhiyun struct completion comp;
80*4882a593Smuzhiyun struct i2c_adapter adap;
81*4882a593Smuzhiyun void __iomem *membase;
82*4882a593Smuzhiyun struct clk *clk;
83*4882a593Smuzhiyun unsigned int len;
84*4882a593Smuzhiyun u8 *buf;
85*4882a593Smuzhiyun u32 enabled_irqs;
86*4882a593Smuzhiyun int error;
87*4882a593Smuzhiyun unsigned int flags;
88*4882a593Smuzhiyun unsigned int busy_cnt;
89*4882a593Smuzhiyun unsigned int clk_cycle;
90*4882a593Smuzhiyun spinlock_t lock; /* IRQ synchronization */
91*4882a593Smuzhiyun };
92*4882a593Smuzhiyun
uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv * priv,bool first)93*4882a593Smuzhiyun static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
94*4882a593Smuzhiyun bool first)
95*4882a593Smuzhiyun {
96*4882a593Smuzhiyun int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun /*
99*4882a593Smuzhiyun * TX-FIFO stores slave address in it for the first access.
100*4882a593Smuzhiyun * Decrement the counter.
101*4882a593Smuzhiyun */
102*4882a593Smuzhiyun if (first)
103*4882a593Smuzhiyun fifo_space--;
104*4882a593Smuzhiyun
105*4882a593Smuzhiyun while (priv->len) {
106*4882a593Smuzhiyun if (fifo_space-- <= 0)
107*4882a593Smuzhiyun break;
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
110*4882a593Smuzhiyun priv->len--;
111*4882a593Smuzhiyun }
112*4882a593Smuzhiyun }
113*4882a593Smuzhiyun
uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv * priv)114*4882a593Smuzhiyun static void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
115*4882a593Smuzhiyun {
116*4882a593Smuzhiyun int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
117*4882a593Smuzhiyun 1 : UNIPHIER_FI2C_FIFO_SIZE;
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun while (priv->len) {
120*4882a593Smuzhiyun if (fifo_left-- <= 0)
121*4882a593Smuzhiyun break;
122*4882a593Smuzhiyun
123*4882a593Smuzhiyun *priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
124*4882a593Smuzhiyun priv->len--;
125*4882a593Smuzhiyun }
126*4882a593Smuzhiyun }
127*4882a593Smuzhiyun
uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv * priv)128*4882a593Smuzhiyun static void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
129*4882a593Smuzhiyun {
130*4882a593Smuzhiyun writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
131*4882a593Smuzhiyun }
132*4882a593Smuzhiyun
uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv * priv,u32 mask)133*4882a593Smuzhiyun static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
134*4882a593Smuzhiyun u32 mask)
135*4882a593Smuzhiyun {
136*4882a593Smuzhiyun writel(mask, priv->membase + UNIPHIER_FI2C_IC);
137*4882a593Smuzhiyun }
138*4882a593Smuzhiyun
uniphier_fi2c_stop(struct uniphier_fi2c_priv * priv)139*4882a593Smuzhiyun static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
140*4882a593Smuzhiyun {
141*4882a593Smuzhiyun priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
142*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
143*4882a593Smuzhiyun writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
144*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_CR);
145*4882a593Smuzhiyun }
146*4882a593Smuzhiyun
uniphier_fi2c_interrupt(int irq,void * dev_id)147*4882a593Smuzhiyun static irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
148*4882a593Smuzhiyun {
149*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = dev_id;
150*4882a593Smuzhiyun u32 irq_status;
151*4882a593Smuzhiyun
152*4882a593Smuzhiyun spin_lock(&priv->lock);
153*4882a593Smuzhiyun
154*4882a593Smuzhiyun irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
155*4882a593Smuzhiyun irq_status &= priv->enabled_irqs;
156*4882a593Smuzhiyun
157*4882a593Smuzhiyun if (irq_status & UNIPHIER_FI2C_INT_STOP)
158*4882a593Smuzhiyun goto complete;
159*4882a593Smuzhiyun
160*4882a593Smuzhiyun if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
161*4882a593Smuzhiyun priv->error = -EAGAIN;
162*4882a593Smuzhiyun goto complete;
163*4882a593Smuzhiyun }
164*4882a593Smuzhiyun
165*4882a593Smuzhiyun if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
166*4882a593Smuzhiyun priv->error = -ENXIO;
167*4882a593Smuzhiyun if (priv->flags & UNIPHIER_FI2C_RD) {
168*4882a593Smuzhiyun /*
169*4882a593Smuzhiyun * work around a hardware bug:
170*4882a593Smuzhiyun * The receive-completed interrupt is never set even if
171*4882a593Smuzhiyun * STOP condition is detected after the address phase
172*4882a593Smuzhiyun * of read transaction fails to get ACK.
173*4882a593Smuzhiyun * To avoid time-out error, we issue STOP here,
174*4882a593Smuzhiyun * but do not wait for its completion.
175*4882a593Smuzhiyun * It should be checked after exiting this handler.
176*4882a593Smuzhiyun */
177*4882a593Smuzhiyun uniphier_fi2c_stop(priv);
178*4882a593Smuzhiyun priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
179*4882a593Smuzhiyun goto complete;
180*4882a593Smuzhiyun }
181*4882a593Smuzhiyun goto stop;
182*4882a593Smuzhiyun }
183*4882a593Smuzhiyun
184*4882a593Smuzhiyun if (irq_status & UNIPHIER_FI2C_INT_TE) {
185*4882a593Smuzhiyun if (!priv->len)
186*4882a593Smuzhiyun goto data_done;
187*4882a593Smuzhiyun
188*4882a593Smuzhiyun uniphier_fi2c_fill_txfifo(priv, false);
189*4882a593Smuzhiyun goto handled;
190*4882a593Smuzhiyun }
191*4882a593Smuzhiyun
192*4882a593Smuzhiyun if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
193*4882a593Smuzhiyun uniphier_fi2c_drain_rxfifo(priv);
194*4882a593Smuzhiyun /*
195*4882a593Smuzhiyun * If the number of bytes to read is multiple of the FIFO size
196*4882a593Smuzhiyun * (msg->len == 8, 16, 24, ...), the INT_RF bit is set a little
197*4882a593Smuzhiyun * earlier than INT_RB. We wait for INT_RB to confirm the
198*4882a593Smuzhiyun * completion of the current message.
199*4882a593Smuzhiyun */
200*4882a593Smuzhiyun if (!priv->len && (irq_status & UNIPHIER_FI2C_INT_RB))
201*4882a593Smuzhiyun goto data_done;
202*4882a593Smuzhiyun
203*4882a593Smuzhiyun if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
204*4882a593Smuzhiyun if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
205*4882a593Smuzhiyun !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
206*4882a593Smuzhiyun priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
207*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
208*4882a593Smuzhiyun priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
209*4882a593Smuzhiyun }
210*4882a593Smuzhiyun if (priv->len <= 1)
211*4882a593Smuzhiyun writel(UNIPHIER_FI2C_CR_MST |
212*4882a593Smuzhiyun UNIPHIER_FI2C_CR_NACK,
213*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_CR);
214*4882a593Smuzhiyun }
215*4882a593Smuzhiyun
216*4882a593Smuzhiyun goto handled;
217*4882a593Smuzhiyun }
218*4882a593Smuzhiyun
219*4882a593Smuzhiyun spin_unlock(&priv->lock);
220*4882a593Smuzhiyun
221*4882a593Smuzhiyun return IRQ_NONE;
222*4882a593Smuzhiyun
223*4882a593Smuzhiyun data_done:
224*4882a593Smuzhiyun if (priv->flags & UNIPHIER_FI2C_STOP) {
225*4882a593Smuzhiyun stop:
226*4882a593Smuzhiyun uniphier_fi2c_stop(priv);
227*4882a593Smuzhiyun } else {
228*4882a593Smuzhiyun complete:
229*4882a593Smuzhiyun priv->enabled_irqs = 0;
230*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
231*4882a593Smuzhiyun complete(&priv->comp);
232*4882a593Smuzhiyun }
233*4882a593Smuzhiyun
234*4882a593Smuzhiyun handled:
235*4882a593Smuzhiyun /*
236*4882a593Smuzhiyun * This controller makes a pause while any bit of the IRQ status is
237*4882a593Smuzhiyun * asserted. Clear the asserted bit to kick the controller just before
238*4882a593Smuzhiyun * exiting the handler.
239*4882a593Smuzhiyun */
240*4882a593Smuzhiyun uniphier_fi2c_clear_irqs(priv, irq_status);
241*4882a593Smuzhiyun
242*4882a593Smuzhiyun spin_unlock(&priv->lock);
243*4882a593Smuzhiyun
244*4882a593Smuzhiyun return IRQ_HANDLED;
245*4882a593Smuzhiyun }
246*4882a593Smuzhiyun
uniphier_fi2c_tx_init(struct uniphier_fi2c_priv * priv,u16 addr,bool repeat)247*4882a593Smuzhiyun static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr,
248*4882a593Smuzhiyun bool repeat)
249*4882a593Smuzhiyun {
250*4882a593Smuzhiyun priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
251*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
252*4882a593Smuzhiyun
253*4882a593Smuzhiyun /* do not use TX byte counter */
254*4882a593Smuzhiyun writel(0, priv->membase + UNIPHIER_FI2C_TBC);
255*4882a593Smuzhiyun /* set slave address */
256*4882a593Smuzhiyun writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
257*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_DTTX);
258*4882a593Smuzhiyun /*
259*4882a593Smuzhiyun * First chunk of data. For a repeated START condition, do not write
260*4882a593Smuzhiyun * data to the TX fifo here to avoid the timing issue.
261*4882a593Smuzhiyun */
262*4882a593Smuzhiyun if (!repeat)
263*4882a593Smuzhiyun uniphier_fi2c_fill_txfifo(priv, true);
264*4882a593Smuzhiyun }
265*4882a593Smuzhiyun
uniphier_fi2c_rx_init(struct uniphier_fi2c_priv * priv,u16 addr)266*4882a593Smuzhiyun static void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
267*4882a593Smuzhiyun {
268*4882a593Smuzhiyun priv->flags |= UNIPHIER_FI2C_RD;
269*4882a593Smuzhiyun
270*4882a593Smuzhiyun if (likely(priv->len < 256)) {
271*4882a593Smuzhiyun /*
272*4882a593Smuzhiyun * If possible, use RX byte counter.
273*4882a593Smuzhiyun * It can automatically handle NACK for the last byte.
274*4882a593Smuzhiyun */
275*4882a593Smuzhiyun writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
276*4882a593Smuzhiyun priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
277*4882a593Smuzhiyun UNIPHIER_FI2C_INT_RB;
278*4882a593Smuzhiyun } else {
279*4882a593Smuzhiyun /*
280*4882a593Smuzhiyun * The byte counter can not count over 256. In this case,
281*4882a593Smuzhiyun * do not use it at all. Drain data when FIFO gets full,
282*4882a593Smuzhiyun * but treat the last portion as a special case.
283*4882a593Smuzhiyun */
284*4882a593Smuzhiyun writel(0, priv->membase + UNIPHIER_FI2C_RBC);
285*4882a593Smuzhiyun priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
286*4882a593Smuzhiyun priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
287*4882a593Smuzhiyun }
288*4882a593Smuzhiyun
289*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
290*4882a593Smuzhiyun
291*4882a593Smuzhiyun /* set slave address with RD bit */
292*4882a593Smuzhiyun writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
293*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_DTTX);
294*4882a593Smuzhiyun }
295*4882a593Smuzhiyun
uniphier_fi2c_reset(struct uniphier_fi2c_priv * priv)296*4882a593Smuzhiyun static void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
297*4882a593Smuzhiyun {
298*4882a593Smuzhiyun writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
299*4882a593Smuzhiyun }
300*4882a593Smuzhiyun
uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv * priv)301*4882a593Smuzhiyun static void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
302*4882a593Smuzhiyun {
303*4882a593Smuzhiyun writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
304*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_BRST);
305*4882a593Smuzhiyun }
306*4882a593Smuzhiyun
uniphier_fi2c_recover(struct uniphier_fi2c_priv * priv)307*4882a593Smuzhiyun static void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
308*4882a593Smuzhiyun {
309*4882a593Smuzhiyun uniphier_fi2c_reset(priv);
310*4882a593Smuzhiyun i2c_recover_bus(&priv->adap);
311*4882a593Smuzhiyun }
312*4882a593Smuzhiyun
uniphier_fi2c_master_xfer_one(struct i2c_adapter * adap,struct i2c_msg * msg,bool repeat,bool stop)313*4882a593Smuzhiyun static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
314*4882a593Smuzhiyun struct i2c_msg *msg, bool repeat,
315*4882a593Smuzhiyun bool stop)
316*4882a593Smuzhiyun {
317*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
318*4882a593Smuzhiyun bool is_read = msg->flags & I2C_M_RD;
319*4882a593Smuzhiyun unsigned long time_left, flags;
320*4882a593Smuzhiyun
321*4882a593Smuzhiyun priv->len = msg->len;
322*4882a593Smuzhiyun priv->buf = msg->buf;
323*4882a593Smuzhiyun priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
324*4882a593Smuzhiyun priv->error = 0;
325*4882a593Smuzhiyun priv->flags = 0;
326*4882a593Smuzhiyun
327*4882a593Smuzhiyun if (stop)
328*4882a593Smuzhiyun priv->flags |= UNIPHIER_FI2C_STOP;
329*4882a593Smuzhiyun
330*4882a593Smuzhiyun reinit_completion(&priv->comp);
331*4882a593Smuzhiyun uniphier_fi2c_clear_irqs(priv, U32_MAX);
332*4882a593Smuzhiyun writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
333*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_RST); /* reset TX/RX FIFO */
334*4882a593Smuzhiyun
335*4882a593Smuzhiyun spin_lock_irqsave(&priv->lock, flags);
336*4882a593Smuzhiyun
337*4882a593Smuzhiyun if (is_read)
338*4882a593Smuzhiyun uniphier_fi2c_rx_init(priv, msg->addr);
339*4882a593Smuzhiyun else
340*4882a593Smuzhiyun uniphier_fi2c_tx_init(priv, msg->addr, repeat);
341*4882a593Smuzhiyun
342*4882a593Smuzhiyun /*
343*4882a593Smuzhiyun * For a repeated START condition, writing a slave address to the FIFO
344*4882a593Smuzhiyun * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
345*4882a593Smuzhiyun * written only for a non-repeated START condition.
346*4882a593Smuzhiyun */
347*4882a593Smuzhiyun if (!repeat)
348*4882a593Smuzhiyun writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
349*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_CR);
350*4882a593Smuzhiyun
351*4882a593Smuzhiyun spin_unlock_irqrestore(&priv->lock, flags);
352*4882a593Smuzhiyun
353*4882a593Smuzhiyun time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
354*4882a593Smuzhiyun
355*4882a593Smuzhiyun spin_lock_irqsave(&priv->lock, flags);
356*4882a593Smuzhiyun priv->enabled_irqs = 0;
357*4882a593Smuzhiyun uniphier_fi2c_set_irqs(priv);
358*4882a593Smuzhiyun spin_unlock_irqrestore(&priv->lock, flags);
359*4882a593Smuzhiyun
360*4882a593Smuzhiyun if (!time_left) {
361*4882a593Smuzhiyun dev_err(&adap->dev, "transaction timeout.\n");
362*4882a593Smuzhiyun uniphier_fi2c_recover(priv);
363*4882a593Smuzhiyun return -ETIMEDOUT;
364*4882a593Smuzhiyun }
365*4882a593Smuzhiyun
366*4882a593Smuzhiyun if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
367*4882a593Smuzhiyun u32 status;
368*4882a593Smuzhiyun int ret;
369*4882a593Smuzhiyun
370*4882a593Smuzhiyun ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR,
371*4882a593Smuzhiyun status,
372*4882a593Smuzhiyun (status & UNIPHIER_FI2C_SR_STS) &&
373*4882a593Smuzhiyun !(status & UNIPHIER_FI2C_SR_BB),
374*4882a593Smuzhiyun 1, 20);
375*4882a593Smuzhiyun if (ret) {
376*4882a593Smuzhiyun dev_err(&adap->dev,
377*4882a593Smuzhiyun "stop condition was not completed.\n");
378*4882a593Smuzhiyun uniphier_fi2c_recover(priv);
379*4882a593Smuzhiyun return ret;
380*4882a593Smuzhiyun }
381*4882a593Smuzhiyun }
382*4882a593Smuzhiyun
383*4882a593Smuzhiyun return priv->error;
384*4882a593Smuzhiyun }
385*4882a593Smuzhiyun
uniphier_fi2c_check_bus_busy(struct i2c_adapter * adap)386*4882a593Smuzhiyun static int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
387*4882a593Smuzhiyun {
388*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
389*4882a593Smuzhiyun
390*4882a593Smuzhiyun if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
391*4882a593Smuzhiyun if (priv->busy_cnt++ > 3) {
392*4882a593Smuzhiyun /*
393*4882a593Smuzhiyun * If bus busy continues too long, it is probably
394*4882a593Smuzhiyun * in a wrong state. Try bus recovery.
395*4882a593Smuzhiyun */
396*4882a593Smuzhiyun uniphier_fi2c_recover(priv);
397*4882a593Smuzhiyun priv->busy_cnt = 0;
398*4882a593Smuzhiyun }
399*4882a593Smuzhiyun
400*4882a593Smuzhiyun return -EAGAIN;
401*4882a593Smuzhiyun }
402*4882a593Smuzhiyun
403*4882a593Smuzhiyun priv->busy_cnt = 0;
404*4882a593Smuzhiyun return 0;
405*4882a593Smuzhiyun }
406*4882a593Smuzhiyun
uniphier_fi2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)407*4882a593Smuzhiyun static int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
408*4882a593Smuzhiyun struct i2c_msg *msgs, int num)
409*4882a593Smuzhiyun {
410*4882a593Smuzhiyun struct i2c_msg *msg, *emsg = msgs + num;
411*4882a593Smuzhiyun bool repeat = false;
412*4882a593Smuzhiyun int ret;
413*4882a593Smuzhiyun
414*4882a593Smuzhiyun ret = uniphier_fi2c_check_bus_busy(adap);
415*4882a593Smuzhiyun if (ret)
416*4882a593Smuzhiyun return ret;
417*4882a593Smuzhiyun
418*4882a593Smuzhiyun for (msg = msgs; msg < emsg; msg++) {
419*4882a593Smuzhiyun /* Emit STOP if it is the last message or I2C_M_STOP is set. */
420*4882a593Smuzhiyun bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
421*4882a593Smuzhiyun
422*4882a593Smuzhiyun ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
423*4882a593Smuzhiyun if (ret)
424*4882a593Smuzhiyun return ret;
425*4882a593Smuzhiyun
426*4882a593Smuzhiyun repeat = !stop;
427*4882a593Smuzhiyun }
428*4882a593Smuzhiyun
429*4882a593Smuzhiyun return num;
430*4882a593Smuzhiyun }
431*4882a593Smuzhiyun
uniphier_fi2c_functionality(struct i2c_adapter * adap)432*4882a593Smuzhiyun static u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
433*4882a593Smuzhiyun {
434*4882a593Smuzhiyun return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
435*4882a593Smuzhiyun }
436*4882a593Smuzhiyun
437*4882a593Smuzhiyun static const struct i2c_algorithm uniphier_fi2c_algo = {
438*4882a593Smuzhiyun .master_xfer = uniphier_fi2c_master_xfer,
439*4882a593Smuzhiyun .functionality = uniphier_fi2c_functionality,
440*4882a593Smuzhiyun };
441*4882a593Smuzhiyun
uniphier_fi2c_get_scl(struct i2c_adapter * adap)442*4882a593Smuzhiyun static int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
443*4882a593Smuzhiyun {
444*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
445*4882a593Smuzhiyun
446*4882a593Smuzhiyun return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
447*4882a593Smuzhiyun UNIPHIER_FI2C_BM_SCLS);
448*4882a593Smuzhiyun }
449*4882a593Smuzhiyun
uniphier_fi2c_set_scl(struct i2c_adapter * adap,int val)450*4882a593Smuzhiyun static void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
451*4882a593Smuzhiyun {
452*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
453*4882a593Smuzhiyun
454*4882a593Smuzhiyun writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
455*4882a593Smuzhiyun priv->membase + UNIPHIER_FI2C_BRST);
456*4882a593Smuzhiyun }
457*4882a593Smuzhiyun
uniphier_fi2c_get_sda(struct i2c_adapter * adap)458*4882a593Smuzhiyun static int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
459*4882a593Smuzhiyun {
460*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
461*4882a593Smuzhiyun
462*4882a593Smuzhiyun return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
463*4882a593Smuzhiyun UNIPHIER_FI2C_BM_SDAS);
464*4882a593Smuzhiyun }
465*4882a593Smuzhiyun
uniphier_fi2c_unprepare_recovery(struct i2c_adapter * adap)466*4882a593Smuzhiyun static void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
467*4882a593Smuzhiyun {
468*4882a593Smuzhiyun uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
469*4882a593Smuzhiyun }
470*4882a593Smuzhiyun
471*4882a593Smuzhiyun static struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
472*4882a593Smuzhiyun .recover_bus = i2c_generic_scl_recovery,
473*4882a593Smuzhiyun .get_scl = uniphier_fi2c_get_scl,
474*4882a593Smuzhiyun .set_scl = uniphier_fi2c_set_scl,
475*4882a593Smuzhiyun .get_sda = uniphier_fi2c_get_sda,
476*4882a593Smuzhiyun .unprepare_recovery = uniphier_fi2c_unprepare_recovery,
477*4882a593Smuzhiyun };
478*4882a593Smuzhiyun
uniphier_fi2c_hw_init(struct uniphier_fi2c_priv * priv)479*4882a593Smuzhiyun static void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
480*4882a593Smuzhiyun {
481*4882a593Smuzhiyun unsigned int cyc = priv->clk_cycle;
482*4882a593Smuzhiyun u32 tmp;
483*4882a593Smuzhiyun
484*4882a593Smuzhiyun tmp = readl(priv->membase + UNIPHIER_FI2C_CR);
485*4882a593Smuzhiyun tmp |= UNIPHIER_FI2C_CR_MST;
486*4882a593Smuzhiyun writel(tmp, priv->membase + UNIPHIER_FI2C_CR);
487*4882a593Smuzhiyun
488*4882a593Smuzhiyun uniphier_fi2c_reset(priv);
489*4882a593Smuzhiyun
490*4882a593Smuzhiyun /*
491*4882a593Smuzhiyun * Standard-mode: tLOW + tHIGH = 10 us
492*4882a593Smuzhiyun * Fast-mode: tLOW + tHIGH = 2.5 us
493*4882a593Smuzhiyun */
494*4882a593Smuzhiyun writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
495*4882a593Smuzhiyun /*
496*4882a593Smuzhiyun * Standard-mode: tLOW = 4.7 us, tHIGH = 4.0 us, tBUF = 4.7 us
497*4882a593Smuzhiyun * Fast-mode: tLOW = 1.3 us, tHIGH = 0.6 us, tBUF = 1.3 us
498*4882a593Smuzhiyun * "tLow/tHIGH = 5/4" meets both.
499*4882a593Smuzhiyun */
500*4882a593Smuzhiyun writel(cyc * 5 / 9, priv->membase + UNIPHIER_FI2C_LCTL);
501*4882a593Smuzhiyun /*
502*4882a593Smuzhiyun * Standard-mode: tHD;STA = 4.0 us, tSU;STA = 4.7 us, tSU;STO = 4.0 us
503*4882a593Smuzhiyun * Fast-mode: tHD;STA = 0.6 us, tSU;STA = 0.6 us, tSU;STO = 0.6 us
504*4882a593Smuzhiyun */
505*4882a593Smuzhiyun writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
506*4882a593Smuzhiyun /*
507*4882a593Smuzhiyun * Standard-mode: tSU;DAT = 250 ns
508*4882a593Smuzhiyun * Fast-mode: tSU;DAT = 100 ns
509*4882a593Smuzhiyun */
510*4882a593Smuzhiyun writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);
511*4882a593Smuzhiyun
512*4882a593Smuzhiyun uniphier_fi2c_prepare_operation(priv);
513*4882a593Smuzhiyun }
514*4882a593Smuzhiyun
uniphier_fi2c_probe(struct platform_device * pdev)515*4882a593Smuzhiyun static int uniphier_fi2c_probe(struct platform_device *pdev)
516*4882a593Smuzhiyun {
517*4882a593Smuzhiyun struct device *dev = &pdev->dev;
518*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv;
519*4882a593Smuzhiyun u32 bus_speed;
520*4882a593Smuzhiyun unsigned long clk_rate;
521*4882a593Smuzhiyun int irq, ret;
522*4882a593Smuzhiyun
523*4882a593Smuzhiyun priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
524*4882a593Smuzhiyun if (!priv)
525*4882a593Smuzhiyun return -ENOMEM;
526*4882a593Smuzhiyun
527*4882a593Smuzhiyun priv->membase = devm_platform_ioremap_resource(pdev, 0);
528*4882a593Smuzhiyun if (IS_ERR(priv->membase))
529*4882a593Smuzhiyun return PTR_ERR(priv->membase);
530*4882a593Smuzhiyun
531*4882a593Smuzhiyun irq = platform_get_irq(pdev, 0);
532*4882a593Smuzhiyun if (irq < 0)
533*4882a593Smuzhiyun return irq;
534*4882a593Smuzhiyun
535*4882a593Smuzhiyun if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
536*4882a593Smuzhiyun bus_speed = I2C_MAX_STANDARD_MODE_FREQ;
537*4882a593Smuzhiyun
538*4882a593Smuzhiyun if (!bus_speed || bus_speed > I2C_MAX_FAST_MODE_FREQ) {
539*4882a593Smuzhiyun dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
540*4882a593Smuzhiyun return -EINVAL;
541*4882a593Smuzhiyun }
542*4882a593Smuzhiyun
543*4882a593Smuzhiyun priv->clk = devm_clk_get(dev, NULL);
544*4882a593Smuzhiyun if (IS_ERR(priv->clk)) {
545*4882a593Smuzhiyun dev_err(dev, "failed to get clock\n");
546*4882a593Smuzhiyun return PTR_ERR(priv->clk);
547*4882a593Smuzhiyun }
548*4882a593Smuzhiyun
549*4882a593Smuzhiyun ret = clk_prepare_enable(priv->clk);
550*4882a593Smuzhiyun if (ret)
551*4882a593Smuzhiyun return ret;
552*4882a593Smuzhiyun
553*4882a593Smuzhiyun clk_rate = clk_get_rate(priv->clk);
554*4882a593Smuzhiyun if (!clk_rate) {
555*4882a593Smuzhiyun dev_err(dev, "input clock rate should not be zero\n");
556*4882a593Smuzhiyun ret = -EINVAL;
557*4882a593Smuzhiyun goto disable_clk;
558*4882a593Smuzhiyun }
559*4882a593Smuzhiyun
560*4882a593Smuzhiyun priv->clk_cycle = clk_rate / bus_speed;
561*4882a593Smuzhiyun init_completion(&priv->comp);
562*4882a593Smuzhiyun spin_lock_init(&priv->lock);
563*4882a593Smuzhiyun priv->adap.owner = THIS_MODULE;
564*4882a593Smuzhiyun priv->adap.algo = &uniphier_fi2c_algo;
565*4882a593Smuzhiyun priv->adap.dev.parent = dev;
566*4882a593Smuzhiyun priv->adap.dev.of_node = dev->of_node;
567*4882a593Smuzhiyun strlcpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
568*4882a593Smuzhiyun priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
569*4882a593Smuzhiyun i2c_set_adapdata(&priv->adap, priv);
570*4882a593Smuzhiyun platform_set_drvdata(pdev, priv);
571*4882a593Smuzhiyun
572*4882a593Smuzhiyun uniphier_fi2c_hw_init(priv);
573*4882a593Smuzhiyun
574*4882a593Smuzhiyun ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
575*4882a593Smuzhiyun pdev->name, priv);
576*4882a593Smuzhiyun if (ret) {
577*4882a593Smuzhiyun dev_err(dev, "failed to request irq %d\n", irq);
578*4882a593Smuzhiyun goto disable_clk;
579*4882a593Smuzhiyun }
580*4882a593Smuzhiyun
581*4882a593Smuzhiyun ret = i2c_add_adapter(&priv->adap);
582*4882a593Smuzhiyun disable_clk:
583*4882a593Smuzhiyun if (ret)
584*4882a593Smuzhiyun clk_disable_unprepare(priv->clk);
585*4882a593Smuzhiyun
586*4882a593Smuzhiyun return ret;
587*4882a593Smuzhiyun }
588*4882a593Smuzhiyun
uniphier_fi2c_remove(struct platform_device * pdev)589*4882a593Smuzhiyun static int uniphier_fi2c_remove(struct platform_device *pdev)
590*4882a593Smuzhiyun {
591*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
592*4882a593Smuzhiyun
593*4882a593Smuzhiyun i2c_del_adapter(&priv->adap);
594*4882a593Smuzhiyun clk_disable_unprepare(priv->clk);
595*4882a593Smuzhiyun
596*4882a593Smuzhiyun return 0;
597*4882a593Smuzhiyun }
598*4882a593Smuzhiyun
uniphier_fi2c_suspend(struct device * dev)599*4882a593Smuzhiyun static int __maybe_unused uniphier_fi2c_suspend(struct device *dev)
600*4882a593Smuzhiyun {
601*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
602*4882a593Smuzhiyun
603*4882a593Smuzhiyun clk_disable_unprepare(priv->clk);
604*4882a593Smuzhiyun
605*4882a593Smuzhiyun return 0;
606*4882a593Smuzhiyun }
607*4882a593Smuzhiyun
uniphier_fi2c_resume(struct device * dev)608*4882a593Smuzhiyun static int __maybe_unused uniphier_fi2c_resume(struct device *dev)
609*4882a593Smuzhiyun {
610*4882a593Smuzhiyun struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
611*4882a593Smuzhiyun int ret;
612*4882a593Smuzhiyun
613*4882a593Smuzhiyun ret = clk_prepare_enable(priv->clk);
614*4882a593Smuzhiyun if (ret)
615*4882a593Smuzhiyun return ret;
616*4882a593Smuzhiyun
617*4882a593Smuzhiyun uniphier_fi2c_hw_init(priv);
618*4882a593Smuzhiyun
619*4882a593Smuzhiyun return 0;
620*4882a593Smuzhiyun }
621*4882a593Smuzhiyun
622*4882a593Smuzhiyun static const struct dev_pm_ops uniphier_fi2c_pm_ops = {
623*4882a593Smuzhiyun SET_SYSTEM_SLEEP_PM_OPS(uniphier_fi2c_suspend, uniphier_fi2c_resume)
624*4882a593Smuzhiyun };
625*4882a593Smuzhiyun
626*4882a593Smuzhiyun static const struct of_device_id uniphier_fi2c_match[] = {
627*4882a593Smuzhiyun { .compatible = "socionext,uniphier-fi2c" },
628*4882a593Smuzhiyun { /* sentinel */ }
629*4882a593Smuzhiyun };
630*4882a593Smuzhiyun MODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
631*4882a593Smuzhiyun
632*4882a593Smuzhiyun static struct platform_driver uniphier_fi2c_drv = {
633*4882a593Smuzhiyun .probe = uniphier_fi2c_probe,
634*4882a593Smuzhiyun .remove = uniphier_fi2c_remove,
635*4882a593Smuzhiyun .driver = {
636*4882a593Smuzhiyun .name = "uniphier-fi2c",
637*4882a593Smuzhiyun .of_match_table = uniphier_fi2c_match,
638*4882a593Smuzhiyun .pm = &uniphier_fi2c_pm_ops,
639*4882a593Smuzhiyun },
640*4882a593Smuzhiyun };
641*4882a593Smuzhiyun module_platform_driver(uniphier_fi2c_drv);
642*4882a593Smuzhiyun
643*4882a593Smuzhiyun MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
644*4882a593Smuzhiyun MODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
645*4882a593Smuzhiyun MODULE_LICENSE("GPL");
646